Reznor AB-2 Series User manual

GAS - FIRED AIR CURTAIN
Manual Part No. D301177 Issue A
®
Please read this document carefully before commencing installation, commissioning and/or servicing.
Please read this document carefully before commencing installation, commissioning and/or servicing.
Leave it with the end user/site agent to be placed in their premises technical file after installation.
WARNING
Nortek Global HVAC (UK) Limited equipment must be installed and maintained in accordance with the requirements of the Codes of Practice or ruies in force. All
external wiring MUST comply with the codes of practice or rules in force in the country of situation.
Improper installation, adjustment, alteration, service, or maintenance can cause property damage, injury, or death. Read the installation, operation, and maintenance
instructions thoroughly before installing or servicing this equipment.
Gas-fired appliances are not designed for use in hazourdous atmospheres containing flammable vapors or combustible dust, in atmospheres containing chlorinated
or halogenated hydrocarbons or in applications with airborne silicone substances.
Should overheating occur, or the gas supply fail to shut off, shut off the manual gas valve to the appliance before shutting off the electrical supply.
Do not use this appliance if any part has been immersed in water. Immediately call a qualified service technician to inspect the appliance and replace any gas control
that hes been immersed in water.
This appliance is not intended for use by persons (including children) with reduced sensory or mental capabilities or lack of experience and knowledge, unless they
have been given supervision or instructions concerning use of the appliance by a person responsible for their safety. Children should be supervised to ensure that they
do not play with the appliance.
FOR YOUR SAFETY
What to do if you smell gas:
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Immediately call your gas supplier.
• Evacuate all personnel.
• Do not store or use petrol or other flammable vapours and liquids in the vicinity
of this or any other appliance.
AB - 2 RANGE
INSTALLATION AND OPERATING MANUAL

PAGE B Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
Contents
General Information ...............................................................................................................1
Dimensions ............................................................................................................................2
Technical Specification ...........................................................................................................3
Installation Details ..................................................................................................................4
Installation Details (Cont)... ....................................................................................................5
Installation Details (Cont)... ....................................................................................................6
Installation Details (Cont)... ....................................................................................................7
Installation Details (Cont)........................................................................................................8
Wiring Details.........................................................................................................................8
Wiring Details (Cont)..............................................................................................................9
Servicing..............................................................................................................................10
Servicing (Cont)....................................................................................................................11
Servicing (Cont)....................................................................................................................12
Commissioning....................................................................................................................13
Commissioning (Cont)..........................................................................................................14
Part Replacement..................................................................................................................15
Part Replacement (Cont).......................................................................................................16
Part Replacement (Cont).......................................................................................................17
Part Replacement (Cont).......................................................................................................18
Part Replacement (Cont).......................................................................................................19
Part Replacement (Cont).......................................................................................................20
Part Replacement (Cont).......................................................................................................21
Part Replacement (Cont).......................................................................................................22
Part Replacement (Cont).......................................................................................................23
Fault Finding.........................................................................................................................24
Fault Finding (Cont)..............................................................................................................25
User Instructions...................................................................................................................26

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 1
Welcome to the new AB-2 Reznor gas fired air
curtain models. Local regulations may vary in the
country of use and it is the installers responsibility
to ensure that such regulations are satisfied.
All installation, assembly, commissioning and
service procedures must be carried out by suitably
qualified competent persons to the statutory
regulations in the country of use.
These instructions refer to products for use in GB
and the IE.
These air curtains are suitable for indoor use
only, and designed to operate at an ambient
temperature between –15°C and 30°C.
When installing, commissioning and servicing is
undertaken on the gas fired air curtains specified
in these instructions, due care and attention
is required to ensure that working at height
regulations are adhered to at the mounting
heights specified.
All dimensions shown are in mm unless otherwise
stated.
The manufacturer reserves the right to alter
specifications without prior notice.
PLEASE READ this document prior
to installation to familiarise yourself
with the components and tools you
require at the various stages.
The primary reason for installing gas fired air
curtains is to prevent the influx of cold outside air
through a door opening into a heated area.
Typical applications include large despatch bay
doors in factories and warehouses, and internal
doors between areas of different temperatures.
Wider door openings can be accommodated by
bolting two or more units together.
Air curtains control the internal climate by
emitting an air stream with enough velocity to
meet the floor so creating an air barrier in the
door area. To prevent the ingress of outside
draughts, the discharge louvre is angled outwards,
so that the air leaving the building meets the wind
trying to enter, thus deflecting it. (See diagrams
below).
Reznor gas fired air curtains provide uniform air
distribution across the full width of the door,
keeping heated or conditioned air inside the
building and stopping the ingress of cold air,
draughts, and dust.
This manual provides detailed information on
the installation of Reznor gas fired air curtains.
It is essential that these products are installed in
accordance with these manufacturers instructions.
General Information

PAGE 2 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
Left side
view
Top view
Mod. A
(mm)
B
(mm)
C
(mm)
D
(mm)
E
(mm)
F
(mm)
Weight
(kg)
AB 175-2 1750 951 456 820 66 1692 160
AB 225-2 2250 951 456 820 66 2192 200
Figure 1. Dimensions (tol. ± 2mm)
Dimensions

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 3
Technical Specification
Model : Air Curtain AB xxxx-2
AB 225N AB 175N AB 225N AB 175N AB 225P AB 175P
Natural gas G20 (I2H) Natural gas G25 (I2L) PropaneG31 (I3P)
Gas Connection ¾ inch external thread
Maximum Supply Pressure (mbar) 25 30 45
Minimum Supply pressure (mbar) 17 20 25
Nominal pressure (mbar) 20 25 37
Gross heat input (kW) 66 45,5 66 45,5 65 45,5
Nett heat input (kW) 59.4 41.0 59.4 41.0 60.2 41.0
Nett heat output (kW) 54.0 37.0 54.0 37.0 54.8 37.0
Gas flow rate (m³/uur) 6.3 4.3 7.4 4.3 - -
Gas flow rate (kg/h) - - - - 4.6 3.2
N° of injectors 5
Injector size (mm) Ø3.4 Ø2.9 Ø3.4 Ø2.9 Ø1.85 Ø1.60
Injector pressure (mbar) 7.25 6.35 10.90 9.30 30.50 26.00
Flue nominal bore (mm) 130
I/D fan
Voltage 230 V 1-fasig 50 Hz
Power Rating 120 W
Current 0,9 A (FLC)
Air Distribution Fans
Type Centrifugal (with integral thermal trip)
Speeds 2
N° of fans 4 3 4 3 4 3
Max. air volume 11000m3/hr (AB 175) 13000m3/hr (AB 225)
Voltage 230V 1PH 50Hz
Power rating (per fan) 1140 W
Current (per fan) 5.2A (FLC)
Start current (per fan 11A
Constitution
Model AB175-2 AB225-2
AB350= X 2
AB400= X 1 X 1
AB450= X 2
AB525= X 3
AB575= X 2 X 1
AB625= X 1 X 2
AB675= X 3
WARNING:
THIS AIR CURTAIN SHOULD NOT
BE INSTALLED WHERE THERE IS A
CORROSIVE ATMOSPHERE.

PAGE 4 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
Installation Details
Health and safety
Reznor air curtains must be installed in accordance
with the relevant provisions of the Gas Safety
(Installations and Use) Regulations 1998. Due
account should also be taken of any obligations
arising from the Health and Safety at Work Act
1974 or relevant codes of practice. In addition
the installation must be carried out in accordance
with the current IEE wiring regulations (BS 7671),
BS 6896 (Industrial & Commercial) and any other
relevant British Standards and Codes of Practice
by a qualified installer. Isolate all electrical supplies
to the heater & control panel before proceeding.
For your own safety we recommend the use of
personal protective equipment when handling this
air curtain.
Check the supporting structure to verify that it
has sufficient load-carrying capacity to support
the unit weight. Suspend the heater only from
the threaded nut retainers or with a manufacturer
provided kit.
DO NOT suspend from the heater cabinet panels.
Do not place or add additional weight to the
suspended heater.
Mounting
Reznor gas fired air curtains are supplied with
mounting brackets pre-fitted, either as single
units, or in multiples, which can be bolted
together to suit various door widths.
The minimum mounting height is 1.8 metres
Suspension by means of threaded rods
De gas-fired air curtains can standard be
suspended using threaded rods M10 and lock
nuts.
Ensure that the structural elements which will be
used to suspend the appliance are adequate to
carry the weight of the appliance.
Leave the unit on the pallet. If the bottom of the
unit is not supported or protected damage can
occur.
The heater is supplied with 8 suspension points.
All points must be used.
Ensure that threaded rods are lock nut secured to
ensure against loosening.
Use a lock nut being carefully tightened in order
not to damage the screw thread.
Gap to be kept to a minimum
Bottom of air curtain
to be level with top of
door opening (1.8m
minimum)
Each unit is fitted with 8 suspensionpoints - all
points must be used! Add a nut to lock the
hanger rod to the heater
Figure 2.
Figure 3.
Figure 4.

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 5
Installation Details (Cont)...
It may be necessary to adjust the position of the
air outlet louvres to provide the correct airflow
across the door opening. This can be done by first
loosening the locking pins (figure 5), The louvres
can now be moved to the desired position and
the locking pins re-tightened.
Note: The AB 225-2 model has two pairs of
lock nuts, whereas the AB 175-2 model only
has one pair.
Suspension by means of fixing
brackets (option).
The use of fixing brackets to suspend the air
curtain is optional (to be specified on order form).
See figure 6.
By using suitable steelwork the air curtains can be
fixed to the building structure.
Multiple air curtains
Multiple air curtains must be fixed to the building
structure by means of threaded rods as described
in section ‘Suspension by means of threaded
rods’.
The use of fixing brackets to install the air curtains
if optional (see section ‘Suspension by means of
threaded brackets (option)’.
Make sure that the multiple air curtains are level
and in the same plane in order to avoid bending
of the system.
Then, the air curtains must be fixed together by
means of four M6 bolts, nuts and washers in the
hereto provided holes in the side of the unit.
Figure 5. Lock Nut
Figure 6.
Figure 7.

PAGE 6 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
Flueing
The gas fired air curtain must be installed with
a fixed flue. The fan is fitted with a 130mm
diameter female outlet. (Flue and fittings can be
supplied by the manufacturer).
The flue pipe should be adequately supported at
regular intervals from the building structure and
terminated externally with a British Gas tested
and certified GC1 terminal.
The maximum flue length is 7m and the
maximum number of bends is two on individually
flued appliances. The flue may be installed
vertically or horizontally, noting that horizontal
flues MUST be terminated vertically. (See figures
8 & 9).
Flue Technical Details
Model AB 225 - 2 AB 175 - 2
Gas type Nat gas (G20) Prop. (G31) Nat. gas (G20) Prop. (G31)
Mass flow rate of flue
gasses (kg/s) 0,03337 0,0332 0,02576 0,0283
Flue gas temp. At flue
outlet (ºC) 188 173 189,5 187
Flue pressure positive
(Pa) 8 8
Ventilation requirements
In buildings having an air change rate of less than
0.5 per hour, additional mechanical or natural
ventilation is required. For detailed information
please see BS6230 section 5.2.2.2.1.1.
Mechanical ventilation
Should be installed to meet a minimum of 0.5 air
changes per hour using appropriately sized fans
interlocked with the heaters.
Natural ventilation
Low level ventilation openings with a free area of
at least 2cm2/kW shall be provided. See section
5.2.2.2.1.2.
Installation Details (Cont)...

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 7
Right Side View
Side View
Installation Details (Cont)...
Figure 8. Typical Vertcial Flue Arrangement
Figure 9. Typical Horizontal Flue Arrangement

PAGE 8 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
Before fitting a horizontal flue, it will be necessary
to rotate the I/D fan through 90º on it`s mounting
bracket to enable the flue to be routed to the rear
of the air curtain as shown in figure 9.
Removal and refitting of the I/D fan is described on
page 19 of this manual, parts replacement.
Note 1: The maximum permissible horizontal flue
length should be calculated using the formula for
equivalent flue sizes shown on the previous page.
Note 2: When the horizontal flue is to pass
through a wall constructed of combustible
material, a suitable approved fireproof sleeve
should be fitted prior to installing the flue pipe.
Installation Details (Cont)...
Wiring Details
Figure 10.

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 9
A customer specific control panel wiring
diagram will be supplied with each air
curtain
Burner controls
The burner controls are mounted in the burner
control cubicle which is an integral part of the air
curtain casing and are accessible by opening a
hinged lid on the right hand side of the air curtain
(see page 15 of this manual for details). The
controls accessible in the cubicle are: gas solenoid
valve, ignition controller, air pressure switch,
flame probe, ignition electrode, reset switch,
orange and white lamps, plus associated wiring
harness. For details see burner wiring diagram on
page 8.
Control panel
The electrical control panel incorporates the
facility to interlock with the door opening
mechanism and automatically switch the air
curtain between high/low speed as the door is
opened and closed. A pair of volt free auxiliary
contacts are required on the door open/close
contactor which closes as the door opens. If this
is not available then a suitably positioned limit
switch and striker plate will need to be fitted to
the door.
The panel incorporates an auto/off/manual
selector switch, which, when in ‘auto’ mode
operates the air curtain in low speed via an
external room thermostat provided the door is
the down position. In the door up position the air
curtain operates in high speed and overrides the
room thermostat The ‘manual’ position overrides
the door interlock and thermostat, and the ‘off ‘
position turns the air curtain off.
A cool/heat selector switch is also incorporated
which allows the air curtain to supply heated air,
or unheated ambient air.
The panel also contains a removable link on the
main terminal rail to allow the air curtain to be
switched on and off remotely via a BMS control
relay.
The panel may also be fitted with optional low
voltage (24V AC) relays for fire alarm/door
contact interlocks.
Regardless of the position of any of the above
switches, the main air fans must be running to
allow the burner to run.
Overheat protection
In the event of any overheat condition there are
two thermal limit controls fitted inside the air
curtain. The controls are factory set and non-
adjustable. The self resetting (cycling) control
activates at 63ºC (AB 225N) and 51.5°C (AB
175N), and the manual reset control at 96ºC. If
either set point is reached, the corresponding
limit control will interrupt the electrical power to
the burner gas valve. The burner will not relight
until the limit control has reset. The manual reset
button is located on top of the heater on the left
hand side of the thermostat cover and can be
accessed after first removing the dust cover. (See
Figs. 22).
These safety devices provide protection in the
event of an air distribution fan motor failure, or
lack of airflow due to restrictions. (For location
see ‘Parts Replacement’ section Figure 40,
and ‘Wiring Details’ section on page 8, burner
controls wiring diagram).
Warning: never attempt to bypass
the thermal limit controls as
hazardous conditions could result.
Wiring Details (Cont)...
Figure 11.

PAGE 10 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
These appliances should be serviced annually by a competent person to ensure safe and efficient
operation. In exceptionally dusty or polluted conditions more frequentservicing may be required.
The manufacturer offers a maintenance service. Details available on request.
Isolate gas and electricity supplies before commencing any work.
Tools Required
The following tools and equipment are
advisable to complete the tasks laid out in this
manual.
Suitable alternative tools may
be used.
Burner assembly
The major components of the burner assembly
can be accessed by removing the two retaining
nuts located on the door so that door can easily
be opened (see figure 29 & 30 on page 17).
In case of insufficient space to reach the
components, remove the cover at the bottom.
Before removing the 4 retaining nuts at the
bottom of the cover, make sure that electrical
contacts of both lamps and switch are
disconnected. We refer to figures 31 & 32 on
page 18. Section ‘Parts Replacment’ explains how
to remove the major components.
Manifold / injectors
Remove the manifold complete with injectors
as described in section ‘Parts Replacement’. The
manifold/injectors should be examined for signs
of debris and cleaned if necessary by blowing
compressed air in the reverse direction to flow.
Individual injectors can be replaced if necessary.
6,2,2 Burners
Access to the burners is achieved by first
detaching and slipping aside the panel of the
control unit (see page 16). The burners can now
be examined and cleaned using a soft brush, or
by blowing compressed air in the reverse direction
to flow. Individual burners can be replaced if
necessary by removing the clamping plate (see
page 19). The complete burner rack can also be
removed following the instructions described in
section 19.
Spark electrode
Remove the spark electrode as described in
section 8 and examine. If it is in good order check
the electrode gap, this should be 3.18mm ±
0.5mm. Adjust the gap if necessary by carefully
bending the earth rod, then re-checking the
measurement.
Flame probe
Remove the flame probe as described in section 8
and examine for signs of erosion.
The probe should be cleaned if necessary
using a fine grade emery paper.
Servicing

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 11
I/D fan
Note: Before removing the I/D fan it will be
necessary to remove the first flue section
after releasing it from the fan/flue adapter.
(See page 19 I/D Fan).
Disconnect and remove I/D fan as described in
section 8. Clean off any dust or deposits using
a soft brush paying particular attention to the
impeller. Also remove any dust or deposits from
the finger guard covering the secondary (cooling)
impeller, and the mesh aperture in the motor
cover. Check that the impeller is free to rotate
and that there is no play in the bearings.
Emitter tubes
External
Brush away any dust on the exterior of the
emitter tubes after first removing the ten screws
retaining the mesh air inlet grille as shown in
Figure 12 below.
Internal
To gain access first remove the bottom cover
as described in section 8 before removing the
screws from the inspection cover.
Remove the screws from the flue cover as shown
in figure 14. Take care not to damage the gasket.
Servicing (Cont)...
Figure 12.
Figure 13.
Figure 14.
Figure 15.

PAGE 12 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
Air outlet louvres
The air outlet louvres should be cleaned with a
soft brush. Check that the louvres are set to the
required angle.
Air distribution fans
The air distribution fans can be
accessed by opening the fan lid as
described in section 8.
Clean off any dust or deposits
with a soft brush paying particular
attention to the impeller. Check that
the impeller spins freely, and that
there is no play in the fan bearings.
The fan(s) can be removed, if
necessary, as described in section 8.
Note: Following any servicing work it
will be necessary to re-commission the
air curtain (See section7).
Servicing (Cont)...

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 13
This appliance must be commissioned by a
suitably qualified engineer
Gas connection
Only persons suitably qualified to work on gas
fired appliances may carry out commissioning and
testing. The whole of the gas service installation
including the meter must be inspected, tested for
gas soundness, and purged in accordance with
the current rules in force.
WARNING: Never use a naked flame
for checking gas soundness.
Air curtain gas pipework
The gas soundness of the air heater pipework
has been checked prior to leaving the factory.
however during installation, connections may
have been loosened. Check the gas soundness
of the appliance pipework using suitable leak
detection fluid. If any leaks are found they must
be rectified immediately.
Check Vacuum Setting
Ensure that the gas and electrical supply to the
control panel is switched on. Ensure that the
control panel heat / cool selector switch is set to
the ‘cool’ position. The air curtain fans will now
start.
• Ensure that the control panel heat/cool selector
switch is now set to the ‘heat’ position. The air
curtain fans will now start and the burner will
fire automatically. Allow the air curtain to heat
up for 15 minutes.
Note: If the air curtain will not start on initial
start up, the ignition controller may be in
lockout position and require resetting. This
may occur especially if the appliance has
been on stand-by for a prolonged period.
Air Curtain Lighting Sequence
AB air curtains are fitted with automatic spark
ignition. When adequate airflow for combustion
is proven by an air proving switch, and a pre-
purge period has elapsed, the integral igniter and
gas control valve operate.
The ignition spark ignites the burner and the
flame is detected by a flame ionisation rod sensor.
If a burner flame is not detected after 5 attempts
then the ignition controller proceeds to lockout
and will require manually resetting. Lockout is
indicated by the illuminated burner rocker switch
on the burner housing, and by a lockout lamp
on the control panel, and can be reset either by
pressing the illuminated burner rocker switch or
the control panel lockout reset button.
Note: If the first lockout reset is not
successful, further investigation will be
required to ascertain the fault.
Burner gas pressure adjustment
The gas pressure is set for the required heat input
before the appliance leaves the factory, normally,
provided the gas supply to the air curtain is in
accordance with the supply pressure described
on the appliance data plate, the operating
pressure will not require adjustment. To check
the pressure, the following procedure should be
carried out:
• Ascertain from ‘Technical Specifications’
section of this document, and the appliance
data plate, the correct operating gas pressure
for the air curtain burner.
• Turn the control panel cool/heat selector
switch to the ‘cool’ position.
Supply Pressure
Test Point
Burner
Pressure
Test
Point
Commissioning
Figure 16.

PAGE 14 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
• Connect a suitable manometer to the burner
pressure test point.
Turn the control panel cool/heat selector
switch to the ‘heat’ position, then wait for
burner to light.
• Observe the burner gas pressure reading on
the manometer and compare to the required
pressure.
• If necessary adjust as follows:
First remove the plastic dust cover from the
regulator adjusting screw. Turn the regulator
adjusting screw anticlockwise to decrease gas
pressure, or clockwise to increase gas pressure.
(See Figure 17) After adjustment replace dust
cover.
• Set control panel heat/cool switch to the
‘cool’ position to turn the burner OFF. Replace
the test point screw (if removed). Relight
the burner and test for gas soundness using
suitable leak detection fluid.
Commissioning (Cont)
Figure 17.

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 15
All servicing/maintenance work on
this air curtain should be carried
out by suitably qualified and
Corgi registered engineer. Before
commencing any work please
ensure that the gas and electricity
supplies are turned off. Always test
for gas soundness with a suitable
leak detection fluid.
Tools Required
Burner / Control assembly
The major components of the burner/control
assembly can be accessed by removing the 2
retaining screws from the door so that door can
be opened (see figure 18 & 19).
It is also possible to take away the door. In this
case the earthing wires must firstly be detached
from the burner relay. Only then can the door be
removed from the appliance.
Figure 21.
Part Replacement
Figure 18.
Figure 19.
Figure 20.

PAGE 16 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
If there is unsufficient space to reach the burner
components, remove the lid at the bottom. Take
care that first the electrical contacts of the two
lamps and the switch are disconnected. See figure
22. Then the four retaining nuts at the bottom of
the lid can be removed (see figure 23).
• Gas valve
Disconnect the mains gas pipe feeding the air
curtain.
Then remove the gas valve as shown in figure 24.
To ease access to the gas valve remove the electric
panel by unscrewing the 2 screws at the top of
the appliance. The panel can then be hung over
the top panel side (see figure 25).
Part Replacement (Cont)
Figure 22.
Figure 23.
Figure 24.
Figure 25.

Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A PAGE 17
Disconnect the quick coupling between gas valve
and gas feeding pipe to remove the gas valve.
Use hereto appropriate tools. See figure 26.
The valve can now be slided downwards and
removed from the unit.
• Burner rack and gas feeding pipe
Follow above steps to disconnect the coupling
between gas valve and gas feeding pipe. By
removing 3 screws the burner rack and the gas
feeding pipe can be removed. Move the burner
rack forward and remove by performing a
rotational motion. See fig 27 & 28.
The gas pipe can now be removed from the
burner rack by unscrewing 4 screws. See figure
29.
Figure 30 shows a gas feeding line with injectors
Part Replacement (Cont)
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.

PAGE 18 Reznor, AB - 2 Gas, GB 2019-08, D301177 Issue A
• Burner tubes
Remove burner tubes by disconnecting the
clamping plate. Remove hereto the screws as
described in figure 31.
• Air pressure switch
Release the electric panel as described in 8.2.1.
Remove the silicon tubing at the top of the air
pressure switch as shown in figure 32.
NB: only a single tube is fitted to the air pressure
switch on the negative pressure side.
Remove now the electrical connections. Remove
hereto the protection cap. Then connections can
be disconnected. See figure 33 and 34.
Part Replacement (Cont)
Figure 31.
Figure 32.
Figure 33.
Figure 34.