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2.0
Section 2.0
Boiler controls and systems
Feedtanks 2.1
Steam injectors 2.2
Level controls 2.3
TDS blowdown controls 2.4
Conductivity sensors 2.5
Sample coolers 2.6
Conductivity meters 2.7
Heat recovery systems 2.8
Blowdown vessels 2.9
Vent heads 2.10
Bottom blowdown systems 2.11
2.0
Boiler controls and systems
2.1
2.1.1
2.1
TI-P401-25
AB Issue 2
Type DH
Flash Condensing Deaerator Heads
1
3
2
3
Head comprises
Item Quantity Description Material
1 1 Mixing Unit Austenitic
Stainless Steel

2 1 Immersion Tube Austenitic
Stainless Steel
3 2 Gasket Silicone Rubber
Application
Spirax Sarco Flash Condensing Deaerator Heads are ideal for
boiler feedtank applications. They are suitable for both new and
retrofit applications. Each head is fitted with a connection for air vent
and recirculating feedwater spray nozzle. The air vent is for the
immediate venting of liberated gases (the connection should also
include a vacuum breaker). For further details on the RFS recirculating
feedwater spray systems see separate literature.
A simple low cost solution for deaerating boiler feedwater at atmospheric pressure
l
Mixes hot and cold incoming flows
l
Liberates oxygen and other gases
l
Stainless steel for long maintenance free life
l
Easy to install
Description
Spirax Sarco flash condensing deaerator head is designed to mix
incoming flows of cold make-up, condensate return and flash steam
to the boiler feedtank. This mixing action is achieved by directing the
downward flow through a baffle arrangement within the unit. This
liberates dissolved gases from the cold make-up, which are vented
to atmosphere. The cold make-up inlet is fitted with a spray screen
which diffuses the flow, increasing its surface area to promote
thorough mixing with the condensate and flash steam.
A Spirax Sarco flash condensing deaerator head consists of three parts:-

— A mixing unit, which is bolted to the top of the tank and is
supplied with connections to customer specification for cold
make-up, condensate return , flash steam from blowdown etc.
— An immersion tube, which distributes the mixed fluids into the
tank and has an integral plate flange which is sandwiched
between the tank and mixing unit flanges.
Immersion tubes are fully described in separate literature.
— Gaskets. Two gaskets are required, one fitted each side on
the immersion tube flange. They are ordered separately.
Available types
The mixing unit is available in five nominal diameters (DN150,
DN200, DN250, DN300, DN400) flanged to BS 4504 PN 16 or BS
1560 Class 150.
Immersion tubes are available in diameters to suit the deaerator
heads and lengths of 950, 1200, 1600 and 2100mm to suit TM
metric feed tanks. Since each deaerator head is built to suit specific
plant requirements we recommend that your local Spirax Sarco
Engineer is contacted for a connection layout sheet and to discuss
your requirements.
Selection table
Total steam Mixing Tank depth
generation Unit 1250 1500 2000 2500
rate (kg/h) DN Mixing unit/immersion tube selection
5000 150
MU 150 MU 150 MU 150 MU 150
IT-950 IT-1200 IT-1600 IT-2100
10000 200
MU 200 MU 200 MU 200 MU 200
IT-950 IT-1200 IT-1600 IT-2100
20000 250

MU 250 MU 250 MU 250 MU 250
IT-950 IT-1200 IT-1600 IT-2100
30000 300
MU 300 MU 300 MU 300 MU 300
IT-950 IT-1200 IT-1600 IT-2100
50000 400
MU 400 MU 400 MU 400 MU 400
IT-950 IT-1200 IT-1600 IT-2100
Limiting conditions
PN 2.5 rating. Suitable for saturated steam 1 bar g, 120°C.
The mixing unit only is hydraulically tested to 2 bar g.
ISO 9001
Feedtanks
2.1
2.1.2
2.1
TI-P401-25 AB Issue 2
Centre line of
connections for
cold make-up,
condensate return,
blowdown flash steam, etc.
65 mm
Connection for recirculating
feedwater spray nozzle
100 mm
Flange for mounting on feedtank
B
A
20 mm

Connection for air vent/
vacuum breaker
How to specify
Atmosperic deaerator head in austentic stainless steel consisting of
mixing unit, immersion tube, and two gaskets. DN 150/200/250/300/
400. Flanged BS4504 PN 16/BS 1560 Class 300.
How to order
To specify a 150mm flash condensing deaerator head flanged
BS 4504 PN 16 (mixing unit plus immersion tube and gaskets to suit
a 1250 mm deep feedtank):-
MU 150 - PN 16
IT 150 - 950 PN 16
2 off gaskets to suit IT 150 - 1200 PN16
Connection details also need to be specified.
Dimensions
(approximate) in millimetres
Mixing Unit
Type A B Weight
MU150_ 175 484 30 kg
MU200_ 200 522 50 kg
MU250_ 220 557 65 kg
MU300_ 250 617 90 kg
MU400_ 290 680 125 kg
For details of immersion tube and gaskets see separate literature.
Boiler controls and systems
2.1
2.1.3
2.1
TI-P401-08
AB Issue 2

Type RFS
Recirculating Feedwater Spray Systems
l
Increases Flash Steam Condensing Capability
l
Improves Thermal Efficiency of the Feedtank
l
Improves Deaeration Within the Feedtank
l
Energy Saving Three Speed Pump
Limiting conditions
The system is designed for pumping water up to 100°C from an
atmospherically vented tank. Max ambient temperature 80°C.
How to specify
1 - Spirax Sarco Recirculating Feedwater Spray System RFS 1
V
1
2
3
1
4
General description
Spirax Sarco recirculating feedwater spray systems type RFS are
designed to provide additional flash steam condensing capacity on
boiler feedtank applications. When the condensate return flowrate is
high and the cold make-up flowrate is intermittent it is likely that
valuable flash steam will be lost through the vent. To ensure that this
flash steam is condensed it is often worthwhile to take feedwater
from a relatively cool part of the feedtank and pump it to a spray
nozzle. Approximately 20% of the feedtank content can be circulated

per hour to provide this additional flash condensing capacity. By
using a low energy pump the thermal efficiency of the feedtank can
be improved.
Available types
Two systems are available: RFS 1 and 2. Each system comprises:
Item Part Material
1 Isolating Valve Carbon steel with stainless steel internals
2 Y-Type Strainer S G Iron with stainless steel screen
3 Electric Pump Cast Iron with stainless steel internals
4 Spray Nozzle Stainless steel
Equipment details
System Isolating Y-Type Spray
Type Valve Strainer Pump Nozzle
RFS 1 Model 10 Figure 12 RP1 1" BSP Male
1" BSP 1" BSP 1" BSP Taper
240V
50Hz
RFS 2 Model 10 Figure 12 RP2 1" BSP Male
1¼” BSP 1¼” BSP 1¼" BSP Taper
240V
50Hz
Application
Systems type RFS are specifically designed for use with Spirax
Sarco Flash Condensing Deaerator Heads. The mixing unit of each
head is fitted with a connection for the spray nozzle.
Selection
A system is selected based on circulating approximately 20% of the
feedtank contents.
Gross Feedtank Recirculating Feedwater
Contents Spray Systems

Litre (kg) Designation Speed Setting
_ 3000 RFS 1 1
3000 to 6000 RFS 1 2
6000 to 8000 RFS 1 3
8000 to 10,000 RFS 2 2
10,000 to 30,000 RFS 2 3
Feedtanks
2.1
2.1.4
2.1
TI-P401-08 AB Issue 2
75
55
186
130
133
82
52
180
271
32
130
Pump Type RP2
Pump Type RP1
Existing
Drain Valve
To Recirculating
Pump Suction
New
Drain Valve

140 mm
28 mm
Dimensions
For details of Isolating valve Model 10 refer to separate literature.
For details of Y-Type strainer Figure 12 refer to separate literature.
Spray Nozzle
A specially designed stainless steel nozzle for distributing the
recirculated feedwater within the flash condensing deaerator head.
Screwed 1" BSP taper male. K
v
= 6.65.
Pump
Three speed induction rotor.
BSP union suction and discharge connections.
Single phase 240v 50 Hz.
System Connection Input Mass
Pump Power
Type Watts kg
RP1 1" BSP Union 40 to 100 2.5
RP2 1¼” BSP Union 85 to 100 2.5
Installation
For new applications
For new applications a specific connection should be incorporated
into the feedtank design. This connection should be the same nominal
size as the pump and should be positioned as near as possible to
the bottom of the tank. The suction side isolating valve, strainer and
pump should be positioned as near to the tank as possible whilst
allowing access for operating the ball valve and removing the strainer
screen. The discharge side pipework should be as short in length as
possible. On RFS 2 systems the discharge pipework should be

reduced to 1" at the spray nozzle.
The pump must be wired in accordance with The Electricity at Work
Regulations, that is, using a direct on line (DOL) starter fitted with a
thermal overload plus local isolator.
For retrofit applications
Where no suitable spare connection is available it is recommended
that the drain connection be utilised by fitting a tee-piece as follows.
It should be noted that the tank does not need to be drained to fit
these pieces.
Caution
For all applications the pump shaft must be horizontal, or slightly
higher at the vent plug end to prevent premature wearing of the top
bearing and shaft.
Operation
The pump should run continuously when the boiler(s) is on load.
Water should flow through the pump at all times while the pump is
running.
Maintenance
At convenient regular intervals it is recommended that the strainer
screen is inspected and any debris removed.
Boiler controls and systems
2.1
TI-P401-07
AB Issue 2
Immersion Tube
Materials
1 Immersion Tube Austenitic stainless steel
2 Gaskets Silicone Rubber
(May be coloured natural, white or red)
How to specify

1 - Immersion Tube IT150-950 in austenitic stainless steel
to suit DN150, PN16 flanges complete with
2 - Silicone rubber gaskets to suit DN150, PN 16.
A simple and effective means of distributing condensate return into boiler feedtanks
l
Easy to install
l
Stainless steel for long maintenance free life
l
Minimises water hammer
General description
The Spirax Sarco Immersion Tube is designed to distribute condensate
return into feedtanks to ensure efficient distribution of hot condensate.
Available types
Available as types IT100
_
, 150
_
, 200
_
, 250
_
, 300
_
and 400
_
with
an integral inside bolt circle sandwich flange to suit BS1560 or
BS4504. They are available in lengths to suit TM metric feedtanks.
Other lengths are available upon request.

Immersion tubes are designated by IT followed by DN followed by
length of immersion tube in mm. e.g. IT250-1600 is DN250 and is
1600mm long from the underside of the flange. It is suitable for a
2000mm deep tank.
Capacity
* Gravity
Condensate Pumped
(with 5% Flash) Condensate
IT type DN kg/h kg/h
IT100_ 100 1 015 2 500
IT150_ 150 2 285 5 000
IT200_ 200 4 065 10 000
IT250_ 250 6 350 20 000
IT300_ 300 9 145 30 000
IT400_ 400 16 255 50 000
* For other quantities of flash steam the capacity may be determined
pro rata i.e. for 10% flash capacity is half that shown.
As a general rule the size of an immersion tube should be at least
one DN larger than the condensate return main.
Limiting conditions
PN2.5 rating. Suitable for condensate at up to 1 bar g, 120°C.
Application
Spirax Sarco Immersion Tubes are ideal for boiler feedtank
applications. They are suitable for both new and retrofit applications.
They offer a much neater and more convenient solution to distributing
condensate return than traditional sparge pipes. Additionally they
reduce the common problem of water hammer found in sparge pipes.
This is achieved by slowing down the flow of the condensate return,
in particular any flash steam, as it enters the immersion tube with its
larger cross sectional area. This gives an opportunity for the flash

steam to pass through the holes into the feedtank without creating
sudden shocks.
When combined with a Mixing Unit they form a flash condensing
deaerator head. For further details see other literature.
1
2
2
2.1.5
ISO 9001
Feedtanks
2.1
TI-P401-07 AB Issue 2
Diameter D
6 to 10 mm
3 mm
Immersion
Tube
Each Immersion
Tube has a number
of holes in a
particular pattern to
suit the stated
capacity
Gasket
Immersion
Tube
Gasket
Top of Tank
Pipe to BS 1600
Schedule 5, 10 or 40

Alternatively,fit vacuum
breaker here, as near to the
elbow as possible.
Ideally fit vacuum breaker
here
Use a blind flange of same
DN as tank connection and
drill hole to suit DN of
condensate return main.
Dimensions Installation
Ideally the immersion tube should be positioned in the middle of the top
of the tank.
The immersion tube can be fitted to a boiler feedtank by the
following methods:-
(1) Using an existing nozzle on the tank top.
The immersion tube is designed so that it can pass through a nozzle
with dimensions according to BS 1600 schedule 40. The sandwich
flange of the immersion tube is equal to the raised face diameter of the
flange for which it is suitable. Gaskets are to be placed above and
below the sandwich flange.
This method is advantageous for feedtanks where no sparge pipes are
fitted since the immersion tube can be inserted without the need for
pipework modifications. Even where perhaps sparge pipes (or the
remains of!) exist, they could be removed and existing pipework utilised.
(2) On new installations a specific connection should be incorporated,
as specified on literature.
It is essential that a vacuum breaker is fitted to the condensate return
main near to the immersion tube. Consider the use of a Spirax Sarco
vacuum breaker VB14. Literature available on request.
Diameter R

Gasket (to be
installed prior to
passing immersion
tube through nozzle)
L
Dimensions
(approximate) in millimetres
Type D R for PN16 R for Class 150
IT100_ 100 162 157
IT150_ 150 212 216
IT200_ 200 268 270
IT250_ 250 320 324
IT300_ 300 378 381
IT400_ 375 490 470
L
IT
___
950 950
IT
___
1200 1200
IT
___
1600 1600
IT
___2100 2100
IT Type Weight (kg)
100-950 7
100-1200 9
100-1600 11

150-950 10
150-1200 12
150-1600 16
200-950 13
200-1200 16
200-1600 21
200-2100 28
250-1200 20
250-1600 27
250-2100 35
300-1200 24
300-1600 32
300-2100 42
400-1200 29
400-1600 39
400-2100 51
2.1.6
Boiler controls and systems
2.1
TI-P409-04
AB Issue 2
WG2
Water Level Gauge
•
Simple gauge glass for low pressure duties
•
Recommended for boiler feedtank applications
•
Available in lengths up to 2200mm
•

Supplied in modular form for maximum versatility
Description
The Spirax Sarco WG 2 level gauge enables an instant visual
check to be made of liquid level in tanks and process vessels.
It consists of a glass tube (plastic also available) mounted in top
and bottom support arms, with packing seals and washers to
prevent leakage and accommodate expansion. The bottom arm
incorporates a three port plug cock to allow isolation and checking
of gauge operation.
An intermediate arm provides additional support and sealing for
gauges with centres longer than 1100 mm, and enables two unequal
length tubes to be used together to give a wide choice of overall
lengths.
Two protector rods mounted either side of the tube reduce the risk
of accidental damage. For greater protection 'C' section protectors
are also available (used with rods).
Limiting conditions
Glass Plastic tube
Maximum working pressure (Pmax) 6.9 bar g 2.0 bar g
Maximum working temperature (Tmax) 152°C 134°C
Maximum saturated steam conditions 4.1 bar g 2.0 bar g
Cold hydraulic test pressure 13.8 bar g 3.0 bar g
Available lengths
(approximate) in millimetres
WG 2 level gauge glasses are designated WG2 followed by /
(centres dimension). Protector rods (in sets of two) and 'C' section
protectors are available in 700, 800, 1000 and 1100 mm lengths.
Two sets are required for gauges with intermediate arms. The
glasses themselves are available in four lengths which may be
paired in the following combinations to give the gauge centre

dimensions below:-
Glass 1 Glass 2 Intermediate Gauge Designation
length length arm centres
686 - No 700 WG2/700
786 - No 800 WG2/800
986 - No 1000 WG2/1000
1086 - No 1100 WG2/1100
686 686 Yes 1400 WG2/1400
686 786 Yes 1500 WG2/1500
786 786 Yes 1600 WG2/1600
686 986 Yes 1700 WG2/1700
786 986 Yes 1800 WG2/1800
786 1086 Yes 1900 WG2/1900
986 986 Yes 2000 WG2/2000
986 1086 Yes 2100 WG2/2100
1086 1086 Yes 2200 WG2/2200
Plastic tubes (complete with 2 off tube supports) are supplied in
1100 mm nominal lengths which can be cut to length with a knife.
2.1
2.1.7
ISO 9001
Feedtanks
2.1
An indication of the plug position is marked on the lever. We
recommend that the water connection is purged and the glass
drained periodically. It is important to check that water flows to drain
and that the level is rapidly re-established in the glass. A slowly
rising level could indicate a partial blockage.
Maintenance
No specific maintenance is required. We recommend that the arms

are checked for leakage periodically and the packing sleeves and
washers renewed if necessary. Always fit new packing sleeves and
washers if the tube has to be replaced.
Dimensions
(approximate) in millimetres
Weights
Top arm 0.65 kg
Intermediate arm 0.62 kg
Bottom arm 0.69 kg
Glass 0.145 kg /100 mm length
Protector rod 0.015 kg /100 mm length
'C' section protector 0.12 kg / 100 mm length
Plastic tube (1100 mm) 0.4 kg
Gland nut
Protector rod Ø4.8
Top plug
85
Gasket
Top arm
Washer
Seal
Washer
Glass
Ø12.7
Intermediate arm
Bottom arm
70
½" BSP Tr (R½)
52.5
¼" BSP Pl

(Rp¼)
Normal Drain glass
Purge water
82
Materials
No Description Material
1 Arm body Gunmetal BS 1400 LG2
2 Protector rods Brass BS 2874 CZ121
3 Glass tube Glass Borosilicate
4 Gland nut Brass BS 2874 CZ121
5 Top plug Brass BS 2874 CZ121
6 Plug cock Gunmetal BS 1400 LG 2
7 Packing sleeve Rubber Nitrile
8 Packing washer Permanite AF 2000
9 Top plug gasket Red fibre BS 216 Grade B
10 'C' section protector Stainless steel Type 304/304L
11 Plastic tube FEP
12 Tube supports Brass BS 2874 CZ132
(used with item 11) (Dezincification resistant)
Installation
WARNING
Your attention is drawn to Safety information leaflet IM-GCM-
10. Tanks or vessels must be drained, vented to atmosphere,
and inlets isolated before work is commenced.
In particular, make sure that any connections which could
carry hot fluids, for example condensate return or flash steam
from blowdown, are isolated.
Top, intermediate, and bottom arms have a ½" BSP taper male
thread (R½) for connection to the tank.
- The tank should have ½"BSP Pl (Rp ½) screwed sockets to take

the top and bottom arms, and intermediate arm if fitted.
Notes:-For certain lengths, the intermediate arm is not equidistant
between the top and bottoms arms. The socket for the intermediate
arm does not need to pierce the tank.
- Fit arms to tank using PTFE tape or a suitable jointing compound.
- Align arms vertically.
- Slacken all gland nuts and remove the
3
/
8
" BSP top arm plug and
gasket.
- Trim plastic tube to the required length (686, 786, 986, or 1086mm).
Each end of the tube requires an internal brass support, (supplied
with the tube).
- Sligthly flatten the ends of the tube with thumb and forefinger
before fitting the supports, to stop them moving during positioning.
- Pass glass/plastic tube through
3
/
8
" BSP thread in top arm and
lower into position.
When an intermediate arm is fitted, the ends of the two
glasses/tubes should touch and the joint should sit between the
intermediate arm glands.
- Gently tighten gland nuts and refit top arm plug and gasket.
- Fit the 'C' section protector (if used) to the front of the unit, then rotate
it so that its hooked edges line up with the protection rod drillings.
- Fit the protector rod(s) through the drillings in the top and

intermediate arms and locate in the blind drillings in the bottom
arm.
- Use the cutouts in the side of the protector to ensure the rods are
correctly positioned.
- The drain connection must not be plugged. It can either be left open
to a tundish, or may be piped to drain.
Operation
The plug cock has three positions:-
Up Purge water connection.
Horizontal Normal operation.
Down Drain glass. This position also isolates the water
connection in case of a broken glass.
Available spares
Glass 686 mm
Glass 786 mm
Glass 986 mm
Glass 1086 mm
Plastic tube (1100 mm) with 2 internal supports
Spare packing seal set consisting of:-
4 off Packing sleeves
8 off Washers (1 fitted each side of the sleeve)
2 off Top plug gaskets
The set is suitable for two re-packings of a gauge with no intermediate
arm or one re-packing of a gauge with an intermediate arm.
Order:- 1 spares pack for Water Level Gauge WG 2.
How to specify
Non-ferrous water level gauge with 3 port plug cock and protector
rods (and 'C' section protector), glass tubes/ plastic tubes.
How to order
Spirax Sarco WG 2/1000 water level gauge with 'C' section protector

and rods.
TI-P409-04 AB Issue 2
'C' section
protector
2.1
2.1.8
Boiler controls and systems
2.1
TI-P409-03
AB Issue 2
Dial Thermometers
General description
Spirax Sarco dial thermometers are reliable and robust instruments
which operate on the bi-metallic coil principle.
Two types are available:-
Austenitic stainless steel body, horizontal mounting, with glass
window. Optional pocket, with a 150mm extension to facilitate
lagging of the tank/vessel.
Aluminium body, vertical mounting, with glass window. Supplied
complete with brass slip-on pocket. Optional version with acrylic
window and stainless steel pocket.
Limiting conditions
Stainless body protection rating IP54
With or without pocket P max 25 bar g T max 120°C
Aluminium body
Maximum pressure P max 6 bar g T max 120/160°C
rating of pocket
Applications
Spirax Sarco dial thermometers are ideal for boiler feed tanks,
condensate pumping and many other industrial processes. Where a

pocket is installed it is possible to remove the thermometer without
draining the vessel contents.
Range
Stainless body 0-120°C
Aluminium body 0-120°C and 0-160°C
Accuracy
Stainless body Complies with DIN 16203 Class 1
Aluminium body Complies with DIN 16203 Class 2
Zero adjustment at pointer.
Dial Thermometer-
Stainless Steel body
Dial Thermometer-
Aluminium body
(supplied with pocket)
2.1
2.1.9
ISO 9001
Feedtanks
2.1
TI-P409-03 AB Issue 2
Installation
Screw the pocket into a ½" BSP connection on the vessel, using
PTFE tape as a thread sealant. The stainless steel dial thermometer
can be screwed directly into the vessel if required.
Position the thermometer so that it will measure a representative
temperature in the vessel. Vertical mounting thermometers have a
minimum insertion depth- see dimension 'H'. Heat conducting paste
is not normally necessary, but may be used if desired.
Materials
Stainless body Aluminium body

Bezel Stainless steel Stainless Steel
Window Glass Glass (acrylic optional)
Stem Stainless steel Brass
Pocket Stainless steel Brass (stainless optional)
How to specify
1 — Horizontal mounting dial thermometer with stainless steel wetted/
exposed parts, IP54 rating.
1 — Pocket with ½" BSPT thread (R½)
1 — Vertical mounting dial thermometer with slip-on pocket 0-120°C
range.
How to order
1 — Spirax Sarco dial thermometer, austenitic stainless steel,
horizontal mounting, 0-120°C.
1 — Pocket with 150mm extension for above.
1 — Spirax Sarco dial thermometer, aluminium body, c/w brass
pocket. 0-120°C range.
E
½" BSP Tr (R½)
F
H
G
I
½" BSP Pl
(G½)
Optional pocket (Stainless)
B
A
D
½" BSP Tr
(R½)

C
Thermometer (Stainless body)
A
B
D
E
F
C
G
H min
½" BSP Tr
(G½A)
Thermometer (Aluminium body) with pocket
Dimensions
(approximate) in millimetres
Stainless body
AB CDE FGHI
100 274 35 8 13 150 18 113 28
Weight Thermometer 0.25kg
Pocket 1.0kg
Aluminium body
A B C D E F G H min
100 48 16 174 35 160 13 65
Weight including pocket 0.4kg
2.1
2.1.10
Boiler controls and systems
2.2
TI-P401-05
AB Issue 6

IN15, IN25M, IN40M
Steam Injectors
• All stainless steel
• Ideal for boiler feedtank heating and de-aeration
• For efficient steam heating of water and other fluids
• Heats, mixes and circulates - no moving parts
• Compact design - minimises noise and vibration
IN15
A
1" BSP Taper or NPT male
BSP or NPT
female
Limiting conditions
Body design rating PN25
Maximum saturated steam condition 17 bar g at 207°C
Maximum heated liquid temperature
90°C
(tank/vessel vented to atmosphere)
Materials
Austenitic stainless steel grade 316L.
K
v
values
Injector IN15 IN25M IN40M
K
v
1.55 9.2 14.5
For conversion C
v
(UK) = K

v
x 0.97 C
v
(US) = K
v
x 1.17
How to order
1 - Spirax Sarco IN25M steam injector screwed 1" BSPT, austenitic
stainless steel grade 316L.
IN25M
IN40M
Description
Spirax Sarco steam injectors use steam to raise the temperature of
water or other liquids. They work by using a jet of steam to draw in
the liquid through radial ports, mix it, and distribute the heated liquid
throughout the tank or vessel. The circulation induced by the
injector ensures thorough mixing and avoids temperature
stratification. Three sizes of injector are available to suit a wide
range of applications.
The smallest, the IN15, has a male and a female thread for direct
mounting to a tank wall from the outside, or to pipework within
the tank.
The IN25M and IN40M are available in male thread or butt-weld
form and are fitted to pipework in the tank, or to a tank wall connection.
For higher capacities, two or more injectors may be mounted in
parallel.
Available types
The IN15 is supplied with a ½" female and 1" male thread, available
in BSPT or NPT.
Options for the larger injectors are shown below:-

IN25M IN40M
BSPT male 1" 1½"
NPT male 1" 1½"
Butt-weld 1" 1½"
Dimensions/weights
(approximate) in mm and kg
Type A B C Weight
IN15 ½" 205 28 0.4
IN25M 1" 84 71 0.8
IN40M 1½" 115 88 1.6
IN15
IN40M
(available screwed
or butt-weld)
IN25M
(available screwed
or butt-weld)
C
B
C
A
B
2.2.1
ISO 9001
Steam injectors
2.2
TI-P401-05 AB Issue 6
Capacity
- selecting a steam injector
The choice of steam injector depends on the flowrate of steam

required to heat the liquid. The table below shows steam injector
capacities in kg/h of injected steam when heating tanks are vented
to atmosphere, and are up to 3 metres deep. The choice of
control valve can affect the steam capacity.
For higher capacities use two or more injectors in parallel.
Injector type IN15 IN25M IN40M
System pressure Saturated steam
bar g capacity kg/h
1 20 135 400
2 48 175 580
3 66 280 805
4 84 350 970
5 102 410 1125
6 120 500 1295
7 138 580 1445
8 156 640 1620
9 174 700 1820
10 192 765 1950
11 210 830 2250
12 228 900 2370
13 246 975 2595
14 264 1045 2710
15 282 1095 2815
16 300 1170 3065
17 318 1225 3200
Installation
WARNING:- Your attention is drawn to Safety Information
Leaflet IM GCM-10. Full Installation and Maintenance
Instructions are provided with each unit. The reference notes
below do not contain sufficient information to install the

product safely, and any attempt to do so may be hazardous.
The injectors are installed at a low level in a tank, ideally along the
centre line, and discharging horizontally along the length. Pipework
may be routed inside or outside the tank. In all cases, steam supply
pipework must be firmly anchored to prevent vibration and stress in
the tank wall. We recommend the use of a suitable thread locking
compound on all threaded connections.
Use the same size pipe as the injector, i.e. 25 mm pipe for IN25M.
Pipe sizes for multiple injector installations are as follows:-
No. of
Type
Minimum
injectors pipe size
2 IN15 20 mm
2 IN40M 65 mm
3 IN40M 80 mm
Allow a minimum of 150 mm between the injector(s) and the sides
and bottom of the tank, and as much length as possible between
the injector outlet and the end of the tank. See IMI for minimum
limits. Space multiple injectors equally across the tank width.
System examples
The tables below give steam capacities for some typical injector /
valve / controller combinations for tanks vented to atmospheric
pressure. Intermediate values may be obtained by linear interpolation.
For alternatives or special applications refer to specific Spirax Sarco
literature or contact our sales engineers.
The tables below are examples only, and the valve / controller
combinations shown may not be available in all markets. Note: Steam
pressure at the injector will be much reduced and proper injection and
mixing may not occur if a smaller valve (or a larger injector) is fitted.

Self-acting control systems example
Injector type IN15 IN25M IN40M
Number off 121123
Valve type / size BX6 DN15 SB DN15 SB DN20 KB51 DN25 KC51 DN40 KC51 DN50
Valve K
v
1.65 2.58 3.81 9.8 16.48 34.0
Controller type
Self-acting control with 2 m capillary Self-acting control with 2 m capillary
Range 1. -20°C to 110°C Range 2. 40°C to 105°C
Steam supply
System saturated steam capacity kg/h
pressure bar g
2 47 82 110 350 580 1 150
4 78 140 200 550 1 000 1 750
6 109 195 280 750 1 400 2 525
8 142 236 360 1 000 1 750 3 200
10 171 310 450 1 200 2 075 3 800
12 201 365 - - 2 500 4 500
13 218 393 - - 2 675 5 000
Electric / pneumatic control systems example
Injector type IN15 IN25M IN40M
Number off 121123
Valve type / size
KE71 / KE73 KE71 / KE73 KE71 / KE73 KE71 / KE73 KE71 / KE73 KE71 / KE73
DN15 DN15 DN15 DN25 DN32 DN50
Valve K
v
1.6 4 4 10 16 36
Steam supply

System saturated steam capacity kg/h
pressure bar g
2 47 96 110 350 580 1 150
4 78 168 200 550 1 100 1 750
6 109 240 280 750 1 400 2 525
8 142 312 360 1 000 1 750 *
10 171 384 450 1 200 2 075 *
12 201 456 650 1 650 **
13 218 492 750 1 750 **
The information given in the tables is empirical and must not be used for critical applications. Use PN5123 or EL5601 actuator, EP5
positioner (PN), SX65 controller (available with mA output for PN actuator, or VMD output for EL actuator), EL2270 sensor and pocket, and
MP2 regulator.
* Consult your local Spirax Sarco sales engineer for information.
2.2.2
Boiler controls and systems
2.2
TI-P401-04
AB Issue 1
Type INS 6 and 10
Direct Steam Injection Heating Systems
A complete system for boiler feedtank, hot water storage and other process heating requirements.
l
Efficient and economic heating
l
Single seated valve giving tight shut-off
l
Simple installation
l
Stainless Seel injector for long life
l

Self-acting control valve requiring no external
l
Quiet operation
power
Optional isolating valve
and
'V' type strainer
General description
Spirax Sarco direct steam injection heating systems type INS are
designed to inject steam into tanks of water or process liquor to
ensure quiet and efficient heating of the tank contents. The injector
draws in cold liquid, mixes it with steam within the injector nozzle
and distributes the hot liquid throughout the tank. In many applications
the circulation induced by the injector is an advantage ensuring
thorough mixing and avoiding temperature stratification.
Available types
Systems are available as type INS 6 and 10, screwed BSP (BS21
parallel) or NPT.
Boiler feedtank applications
Oxygen must be removed from boiler water if corrosion is to be
prevented. Oxygen can be removed in two ways. Either, by the use
of oxygen scavenging chemicals or by thermal deaeration: the
dissolved oxygen content of water at 20°C is 9 ppm, at 60°C is
5ppm and at 90°C is just under 2 ppm. By heating the boiler feed
water typically to 80 - 85°C to remove the bulk of the oxygen and
using oxygen scavenging chemicals in the feeding after the tank the
use of chemicals can be reduced by up to 75%. Additionally, boiler
efficiency may be increased since blowdown requirements may be
lowered. The fitting of a dial thermometer on the tank is
recommended, a suitable product is available from the SPIRAX

SARCO range see TIS 10.9110.
System comprises
No. Part Material
1 Control Valve Bronze
2 Controller/Sensor Brass
3 Sensor Pocket Stainless steel
4 Injector Stainless steel
5 Vacuum Breaker Brass
Installation
Spirax Sarco direct steam injection heating systems are designed
to operate with the minimum of noise provided the installation is
correct. For full details refer to AIS 10.1406.
Regulations
Some installations will be covered by standard specification M & E
No. 3 (1986). M & E No. 3 clause 7.10.1 states that valve bodies up
to and including DN 50 used in steam systems shall be bronze. For
these applications Spirax Sarco Direct Steam Injection Heating
Systems are ideal.
How to specify
1 — Spirax Sarco Direct Steam Injection System type INS 6 screwed
BSP.
3
4
2
5
1
Please note: the mounting position
of the injector into the tank is drawn
out of position for clarity
2.2.3

Steam injectors
2.2
TI-P401-04 AB Issue 1
Capacities
System capacities in kg/h of injected steam when heating tanks vented to atmospheric pressure.
System Type INS 6 INS 10
Control Valve Size DN 15 with 6mm orifice DN 15
Steam supply pressure Capacities in kg/h of saturated steam
barg psig
229 47 82
3 44 63 110
4 58 78 140
5 73 94 168
6 87 109 195
7 102 125 223
8 116 142 236
9 131 155 282
10 145 171 310
11 160 186 338
12 174 201 365
13 189 218 393
Where steam supply pressures are higher consider the use of a pressure reducing valve or alternatively, the use of a combined pressure
reducing and temperature control valve. Please consult us for a suitable type.
Equipment details
System Type Control Valve * Controller Type and Range Sensor Pocket Steam Injector Vacuum Breaker
INS 6 DN 15 BX 6
128 with 2m capillary —
Stainless Steel — 1"
IN15 — 1 off
VB 14 — ½"

range 1 (-20 to 110°C) ½" female x 1" male
INS 10 DN 15 SB
128 with 2m capillary —
Stainless Steel — 1"
IN15 — 2 off
VB 14 — ½"
range 1 (-20 to 110°C) ½" female x 1" male
All equipment is available screwed BSP or NPT. * Control valves type BX6 and SB are normally open single seat valves.
Further details
(of associated equipment)
BX6 Control Valve TIS 1.800
SB Control Valve TIS 1.801
Type 128 Controller TIS 1.900
IN15 Steam Injector TIS 10.1411
VB14 Vacuum Breaker TIS 4.103
Fig 12 Y-Type Strainer TIS 7.401
Model 10 Ball Valve TIS 7.214
HV3 Stop Valve TIS 7.227
Dial Thermometer TIS 10.9110
A Y-type strainer is recommended upstream of the control valve.
The Y-type strainer should normally be the same size as the steam
supply pipeline. Consider a SPIRAX SARCO brass/bronze Fig. 12
(See TIS 7.401).
An isolating valve is recommended upstream of the Y-type strainer.
Consider the use of SPIRAX SARCO Model 10 Ball Valve in carbon
steel (See TIS 7.214) or the HV3 Stop Valve in bronze (See TIS
7.227).
2.2.4
Boiler controls and systems
2.2

TI-P401-03
AB Issue 2
Type INS
Direct Steam Injection Heating Systems
2.2.5
A complete system for boiler feedtank, hot water storage
and other industrial process heating requirements.
·
Stainless steel injector for long life and, with no moving parts is maintenance free
·
Self-acting system requiring no external power supply
·
Efficient and economic heating
·
Quiet operation
General description
Spirax Sarco INS direct steam injection heating systems are designed
to inject steam into tanks of water or process liquor to ensure quiet
and efficient heating of the tank contents. The injector draws in cold
liquid, mixes it with the steam within the injector and distributes the
hot liquid throughout the tank. In many applications the circulation
induced by the injector is an advantage ensuring thorough mixing
and avoiding temperature stratification.
Available types
Systems are available as type INS15, 20, 25, 40, 50, 65 and 80.
The injectors are for horizontal installation.
The selection of a system depends on the flowrate of steam required
to heat the tank contents and the steam supply pressure to the
control valve.
System comprises

No. Part Material
1 Control valve Bronze/gunmetal
2 Controller and sensor Brass
3 Sensor pocket Stainless steel
4 Horizontal injector Stainless steel
5 Vacuum breaker Brass
Boiler feedtank applications
Oxygen must be removed from boiler water if corrosion is to be
prevented. Oxygen can be removed in two ways, either, by the
use of oxygen scavenging chemicals or by thermal de-aeration.
The dissolved oxygen content of water at 20°C is 9 ppm, at 60°C is
5 ppm and at 90°C is just under 2 ppm. By heating the boiler
feedwater typically to 85-90°C to remove the bulk of the oxygen and
using oxygen scavenging chemicals in the feedline after the tank the
use of chemicals can be reduced by up to 75%.
Additionally, boiler efficiency may be increased since blowdown
requirements may be lowered.
Installation
Spirax Sarco direct steam injection heating systems are designed
to operate with the minimum of noise provided the installation is
correct.
How to order
Example: 1 off Spirax Sarco direct steam injection heating system
type INS15.
Stop valve
1
5
3
Y-type strainer
Dial

thermometer
2
4
Steam injectors
2.2
TI-P401-03 AB Issue 2
2.2.6
Capacities
System capacities in kg/h injected steam when heating tanks vented to atmospheric pressure.
System type INS15 INS20 INS25 INS40 INS50 INS65 INS80
Control valve Size ½" BSP ¾" BSP 1" BSP 1½" BSP 2" BSP 2½" BSP 3" BSP
Steam supply pressure
Capacities in kg/h of saturated steam
bar g psi g
2 29 87 110 350 580 1 150 2 500 3 700
3 44120 160 425 750 1 400 3 350 4 900
4 58150 200 550 1 000 1 750 4 200 6 000
5 73180 240 650 1 150 2 100 5 000 7 200
6 87215 280 750 1 400 2 525 5 800 8 400
6.9 100 237 316 840 1 535 2 800 6 500 9 450
7 102 240 320 850 1 550 2 950 6 600 9 550
8 116 275 360 1 000 1 750 3 200 7 400 10 700
8.2 118 278 370 1 020 1 780 3 280 7 550 10 950
9 131 290 410 1 100 1 900 3 600 8 200 11 850
10 145 315 450 1 200 2 075 3 800 9 000 13 000
10.3 150 325 460 1 230 2 135 3 920 - -
11 160 350 - - 2 275 4 200 - -
12 174 375 - - 2 500 4 500 - -
13 189 400 - - 2 675 5 000 - -
Where steam supply pressures are higher consider the use of a pressure reducing valve or alternatively, the use of a combined pressure

reducing and temperature control valve. Please consult Spirax Sarco for a suitable type.
Equipment details
System type Control valve type* Controller type Sensor pocket Steam injector Vacuum breaker
INS15 SB ½" BSP 128 with 2 m capillary
Range 1 S. Steel to suit 128 1 x IN25M
VB14 ½" BSP
-20 to 110°C 1" BSP 1" BSP
INS20 SB ¾" BSP 128 with 2 m capillary
Range 1 S. Steel to suit 128 1 x IN25M
VB14 ½" BSP
-20 to 110°C 1" BSP 1" BSP
INS25 KB51 1" BSP 128 with 2 m capillary
Range 1 S. Steel to suit 128 1 x IN40M
VB14 ½" BSP
-20 to 110°C 1" BSP 1½" BSP
INS40 KC51 1½" BSP 121 with 2 m capillary
Range 2 S. Steel to suit 121 2 x IN40M
VB14 ½" BSP
40 to 105°C 1" BSP 1½" BSP
INS50 KC51 2" BSP 121 with 2 m capillary
Range 2 S. Steel to suit 121 3 x IN40M
VB14 ½" BSP
40 to 105°C 1" BSP 1½" BSP
INS65 NS 2½" BSP 121 with 2 m capillary
Range 2 S. steel to suit 121 5 x IN40M
VB14 ½" BSP
40 to 105°C 1" BSP 1½" BSP
INS80 NS 3" BSP 121 with 2 m capillary
Range 2 S. steel to suit 121 7 x IN40M
VB14 ½" BSP

40 to 105°C 1" BSP 1½" BSP
*
Control valve type SB is bronze, single seat, normally open, direct acting.
Control valves type KB51 and KC51 are bronze, single seat, normally open, bellows balanced, direct acting.
Control valves type NS is gunmetal double seat, normally open, stainless steel trim, direct acting.
A Y-type strainer is recommended upstream of the control valve. The Y-type strainer should normally be the same size as the steam supply
pipeline. Consider a Spirax Sarco brass/bronze Fig. 12.
An isolating valve is recommended upstream of the Y-type strainer.
Consider the use of a Spirax Sarco carbon steel ball valve type M10 or bronze stop valve type HV2.
Boiler controls and systems
2.2
2.2.7
Steam injectors
2.2
TI-P401-06
AB Issue 2
Type SD
Steam Distributor
L
D
l
Simple installation — no special supports required.
l
Compact, lightweight and strong.
l
Stainless steel for long life.
l
Eliminates waterhammer.
l
Quiet operation.

General description
Spirax Sarco steam distributors type SD are designed to distribute
low pressure steam into tanks of water. They ensure rapid
condensation of the steam and efficient heating of the water. The
hole configuration provides a self-regulating control feature ensuring
that holes progressively come into use as the steam flowrate
increases. An internal stainless steel mesh ensures quiet operation.
Available types
SD40S, 50S and 80S screwed BSP (BS 21 parallel) or NPT.
SD80, 100 and 150 flanged to suit BS4504 PN16 or BS1560 Class
150.
Limiting conditions
Maximum saturated steam conditions 1.7 bar g 130°C
For quietest operation it is recommended that steam pressure is
reduced to below 1 bar g
Materials
Austenitic stainless steel.
Dimensions
(approximate) in millimetres
Steam Distributor Connection
Type D L
SD 40S 1½" BSP or NPT 100 70
Female
SD 50S 2" BSP or NPT 150 85
Female
SD 80S 3" BSP or NPT 215 110
Female
SD 80 80mm PN16 or 215 180
Class 150
SD 100 100mm PN16 or 235 210

Class 150
SD 150 150mm PN16 or 305 220
Class 150
Capacities
Each distributor has a number of holes. The flow of steam through
the holes depends on the differential pressure available. The table
below shows capacities in kg/h of distributed steam when heating
tanks which are vented to atmospheric pressure.
Steam Distributor
Steam Supply Type SD
Pressure bar g
40S 50S 80S & 80 100 150
0.2 99 176 396 643 935
0.4 135 240 540 877 1275
0.6 171 304 684 1111 1615
0.8 198 352 792 1287 1870
1.0 225 400 900 1462 2125
Intermediate values may be obtained by linear interpolation.
For higher capacities use 2 or more distributors in parallel.
Applications
1. Boiler blowdown heat recovery
Steam distributors type SD are ideal for supplementing the heating
of boiler feedwater tanks using flash steam. When used in conjunction
with a flash vessel, as part of a boiler blowdown heat recovery
system, flash steam recovery is simple, of low capital cost and is
maintenance free. Additionally, the flash steam is condensed to
pure water reducing the amount of make-up water and chemical
treatment required. Generally for sizing purposes use a differential
pressure of 0.4 bar.
2. Sparge pipes

Direct steam injection at low steam pressures has been traditionally
carried out using sparge pipes which are made from a length of
pipe. These have a disadvantage in that they must be made to suit
each and every application. However by utilising a more universal
design Spirax Sarco can offer a "steam distributor" that will suit most
applications. For higher steam pressures Spirax Sarco steam injectors
may be used.
Installation
Fit the end of a vertical downpipe in the tank so that the bottom of
the distributor is at about
1
/
3

of the working depth of tank. The piping
between the steam source and distributor should be the same
nominal size as the connection on the distributor. It is recommended
that the piping is less than 10m in length in order to minimise the
pressure drop.
How to specify
1 — Spirax Sarco steam distributor Type SD40S screwed 1½" BSP.
2.2.8
Boiler controls and systems
2.3
2.3.1
AI-P402-15
AB Issue 5
Tank Level Control (On/Off)
Power
Alarm

LC1300
Pump
Alarm
Description
The Spirax Sarco (on/off) tank level control system is suitable for most qualities of industrial waters where the electrical conductivity is greater
than 10 micro Siemens/cm or 10 ppm. The controllers should be mounted in an enclosure or panel to provide environmental protection. They
may be mounted on a 'top-hat' DIN rail using the mounting clip provided or the controller base may be screwed directly to a chassis plate.
Fig. 1 Pump fill with low level alarm
Power
Alarm
LC1300
Pump
Alarm
LC1300 controller
Pump
contactor
Pump
Pump off
Pump on
Low level alarm
LP10-4 probe
t
High level alarm
t
t
t
Applications
On/off tank level control can be achieved using the
Spirax Sarco LC1300 controller in conjunction with
LP10-4 level probes. The LC1300 controller is able to

provide the following functions:-
a) Pump-in control with low or high alarm or
b) Pump-out control with low or high alarm or
c) High or low alarm plus extra low alarm.
Typical arrangements
We recommend the probe is in a protection tube. The
metal tank generally forms the earth return. However,
where the tank is of a non-conductive material one of
the probe electrodes should be used to provide the
earth return.
Fig. 2 Valve control fill with low level alarm
Low level alarm
Valve open
Valve closed
Solenoid
valve
LC1300 controller
LP10-4 probe
High level alarm
t
t
t
t
Level controls
2.3
2.3.2
AI-P402-15 AB Issue 5
Power
Alarm
LC1300

Pump
Alarm
LC1300 controller
Pump contactor
LP10-4 probe
Pump
High level
Pump on
Earth return
Flow to process
Pump off
Fig. 4 Pump fill with high level alarm (with polypropylene tank)
Power
Alarm
LC1300
Pump
Alarm
LC1300 controller
High level
Glass lining
Alarm
Low level
LP10-4 probe
Earth return
Fig. 3 Tank alarms on glass lined vessel
t
t
t
t
t

t
Boiler controls and systems
2.3
Description
The system comprises a Spirax Sarco LP20 level probe and PA20 preamplifier together with either an LC2200 or LC2500 controller, and
associated valves and fittings, depending on the application.
Separate literature is available which explains the individual equipment in detail.
Applications
Spirax Sarco capacitance probe based systems can be used to monitor and control the level of a wide range of conductive liquids.
The controllers may be used in a variety of configurations for many different filling or emptying applications.
For modulating level control, Spirax Sarco supply a control valve with an electric actuator and 1000 ohm feedback potentiometer.
The LC2200 and LC2500 level controllers should be mounted in a metal or plastic enclosure to provide environmental protection. Spirax
Sarco are able to supply suitable enclosures.
Controllers may be mounted on a 'top hat' DIN rail using the mounting clip provided or the controller base may be screwed directly to a chassis plate.
If the tank or vessel contents are turbulent the probe should be mounted in a protection tube.
Typical arrangements
The system provides the following options:-
Modulating fill control with high alarm
Modulating fill control with low alarm
Using the LC2200 controller
Modulating empty control with high alarm
Modulating empty control with low alarm
On/off fill control with high alarm
On/off fill control with low alarm

Using the LC2500 controller
On/off empty control with high alarm
(with pump contactor)
On/off empty control with low alarm
(with pump contactor)

Examples of the many level control duties possible
AI-P402-16
AB Issue 4
Level Control (On/Off or Modulating)
using Capacitance Probes
Control valve
Make-up water
LP20 probe/
PA20 preamplifier
Low level alarm
Valve modulates to
maintain water level
within this band.
Condensate return
to boiler house
Pump
Pump off
Pump
contactor
Pump on
High level alarm
LP20 probe/
PA20 preamplifier
Fig. 1 Boiler feedtank make-up with modulating control
and low level alarm.
Fig. 2 Condensate return tank on/off emptying control
with high level alarm
LC2200 controller
LC2500 controller
t

2.3.3
Level controls
2.3
AI-P402-16 AB Issue 4
Control valve
Make-up water
Flow to process
Valve modulates to
maintain water level
within this band
LP20 probe/
PA20 preamplifier
Fig. 4 Drainage control of a large process pressure vessel;modulating control with high level alarm.
High level alarm
LC2200 controller
Control valve
To drain
LP20 probe/
PA20 preamplifier
High level alarm
LC2200 controller
Fig. 3 Process water tank with modulating fill control, and high level alarm
Valve modulates to
maintain water level
within this band
2.3.4
Boiler controls and systems
2.3
AI-P402-08
AB Issue 4

LCS1000
Level Control Systems - Chamber Mounted
2.3.5
Alarm
AlarmPower
LC1300
LC1300
Power
Alarm Pump
Typical installation
LCS1000 boiler level control systems are suitable for
automatically controlled steam boilers and provide the control
and alarm functions specified by British Standards in BS 2790, by
the Health and Safety Executive in PM5 and by SAFed (PSG2).
The LCS1000 systems require daily manual testing as specified in
PM5 and a trained boiler attendant should be on site at all times
the boiler is in operation.
The level controls and level alarms are probably the most important
controls on the boiler for ensuring safety and should only be
installed and maintained by suitably trained personnel.
Spirax Sarco can install, commission and provide a regular
maintenance service.
For details of installation, wiring and maintenance see the
Installation and Maintenance Instructions of the individual
components of the system.
Boiler
To drain tundish or
blowdown vessel
Chamber
Sequencing purge valves

LP10-4
probe
LP10-4
probe
High alarm
Pump off
Pump on
1st low
2nd low
Not used
Installation and testing
of on/off boiler water level controls in external chambers
Not used
LC1300 LC1300
Level controls
2.3
AI-P402-08 AB Issue 4
2.3.6
Daily test (or once per shift)
1. With the burner firing, operate the sequencing purge valve on the
1st low alarm chamber to purge through the water connection to
the chamber and to empty the chamber to drain. Check that the
burner shuts down and that the 1st low alarm lamp and bell
operates.
2. Return the sequencing purge valve to 'normal'. The alarm should
cancel and the burner refire.
3. With the burner firing repeat the test on the 2nd low alarm
chamber. The alarm should 'lockout' and should require manual
resetting before the burner will refire.
4. On completion of the test, check that all valves and controls are

in their normal operating position and that the water level is
correct in the level gauge glass. The boiler should not be left until
the person carrying out the test is satisfied it is operating
normally.
Weekly test
The weekly test should be carried out or witnessed by a responsible
person who appreciates the hazards involved and has been suitably
trained in the safe operation of the boiler and its controls. At no time
during the test should the water be lowered to the extent that it
disappears from the gauge glass.
1. With the feedpump switched off, allow the water level to fall by
evaporation until the burner shuts down at 1st low alarm.
2. Blow down the boiler until the 2nd low alarm sounds and the
burner controls go to lockout.
3. Raise the water level to normal, reset the lockout, then continue
to raise the water level to the high alarm level. Check that the
high alarm sounds.
4. Return all valves and controls to normal and monitor the boiler
until satisfied that it is operating normally.
Quarterly inspection
The Health and Safety Executive recommend from experience
that the boiler controls should be serviced at least at
quarterly intervals. Where the regular tests are carried out properly
in a well run boiler house with good water treatment, it may be
that only an annual inspection of the probes etc. is required.
This is a matter, however, for the user to decide in liaison with
his insurance company inspector in order to determine a
sensible inspection programme to suit the individual boiler plant.
We recommend a regular inspection as follows:
1. Inspect the probe plugs for moisture.

2. Unscrew the probes and wipe away any dirt from the probe
tips. If any hard scale is present it may be an indication of
more serious scale formation elsewhere in the boiler.
Investigate water treatment.
3. Remove the covers from the sequencing purge valves and
inspect the water connections to the boiler. Clean as necessary.
4. Inspect the wiring and controllers for damage.
5. Reassemble, refill the boiler and carry out a full functional check.