11
14
8.
MAINTENANCE
NOTE: It is recommended that this appliance be serviced at intervals of no less than 12 months.
IMPORTANT: Ensure that the gas and electricity supplies are isolated before commencing any maintenance or replacement of
components. Because the appliance is room sealed, it is also imperative that if at any stage of repairs the gasket on the sealing
plate is damaged it MUST be replaced! After completion of any maintenance, always test for gas soundness and carry out a
complete functional test of the appliance in accordance with the Commissioning Instructions at paragraphs 6.1 to 6.6 inclusive.
8.1
ROUTINE MAINTENANCE:
8.1.1
Operate the appliance and check for the correct function of the burner and controls.
8.1.2
Turn OFF the gas and electrical supplies to the appliance.
8.1.3
Remove the air heater front panel.
8.1.4
Remove and check the return air filter/cleaner for cleanliness, remove and clean the air circulation fan as detailed in
para 10.6.
8.1.5
Remove the burner and controls assembly as detailed in para 10.2, inspect and clean the main burner and injector as
necessary. Examine the main burner for cracks, including hairline cracks, exchanging the burner as necessary.
8.1.6
Inspect and clear the ignition burner orifice.
8.1.7
Clean the heat exchanger flueways by thoroughly brushing from above and below.
8.1.8
By viewing through the fan aperture, and using a torch or similar, examine the heat exchanger externally for signs of
cracks or holes, particularly around welded joints.
8.1.9
Using a torch or similar, introduce a light source into the heat exchanger burner aperture and upper access port, and
again examine the heat exchanger for signs of cracks or holes, particularly around welded joints, whilst again viewing
through the fan aperture.
8.1.10 Refit the air circulation fan, burner and controls assembly, and air filter/air cleaner.
8.1.11 Allow the air heater to operate for approximately 15 minutes to ensure stability and, with the main burner lit, ensure
that the operation of the air circulation fan does not affect the main burner flame profile.
8.1.12 Locate the flue gas test point (see fig.1) and attach a flue gas analyser to the test point in accordance with the
manufacturer’s instructions.
NOTE:
the CO/CO
2
ratio should be no greater than 0.008
8.1.13 Fully commission the appliance in accordance with paragraphs 6 and 8.
NOTE
: The flue gas test MUST NOT be used as an alternative to servicing the heater!
8.2
MULTIFUNCTION CONTROL AND BURNER ASSEMBLY REMOVAL:
NOTE:
Both the burner and ignition burner assemblies MUST be removed as a complete unit together with the multifunction
control.
PROCEDURE:
8.2.1
Ensure that the gas and electrical supplies are switched OFF.
8.2.2
Remove the front door from the heater.
8.2.3
Remove the fixing screws that hold the sealing panel in place and carefully remove the panel.
8.2.4
Disconnect the electronic module from the multifunction control by removing the securing bolt and sliding it towards
the left of the heater unit, taking care not to cause damage.
8.2.5
Remove the burner assembly fixing screws.
8.2.6
Break the gas supply at the gas union and remove the gas feed pipe fixing screw.
8.2.7
Whilst supporting the assembly, carefully remove the fixing screws securing the multifunction control.
8.2.8
Carefully remove the complete assembly, by sliding the sealing grommet out of the bulkhead, taking care not to cause
damage to the grommet!
8.2.9
Refitting the burner assembly is a reverse procedure of the above instructions.
8.3
BURNER ASSEMBLY CLEANING:
8.3.1
Remove the burner assembly as detailed above.
8.3.2
Disconnect the ignition burner gas feed pipe from the ignition burner
8.3.3
Release the single screw, nut and washer securing the ignition burner to the main burner and remove the ignition
burner.
Table. 4
Control module fault indications
NOTE:
To disconnect the module,
LIFT the connector blocks
off the circuit board. DO
NOT remove the wires
from the connector blocks!
8.10.6 Carefully withdraw the fan and its gasket from the collecter box, taking care not to damage the fan blades.
8.10.7 Remove all dust from both the impeller and motor, taking care not to disturb the balance of the fan.
8.10.8 Refitting/replacement is in reverse order.
9.
DEFECT DIAGNOSIS
The following table shows the LED status indicator display and the corresponding fault condition. It should be noted that under
certain conditions the red LED relating to the air heater may flash. This is part of the control sequence and the module should reset
automatically. It is ONLY necessary to press the “RESET” button if the red LED is continually illuminated !
Fig. 11
Control module, showing connector blocks.
Connector blocks
LED
Display
Cycle
Fault Condition
0
Running
None: all is well
1
Air Proving
Air switch closed
2
Air Proving
Gas valve relay ON
3
Air Proving
Air switch closure failed
4
Prove Heater Relay
Gas valve current, relay should be open
5
Prove Heater Valve
None (wait for Ignition Burner)
6
Prove Heater Valve
Flame failure
7
Prove Circulator Relay
Gas valve current, relay should be open
8
Prove Circulator Valve
None (wait for Ignition Burner)
9
Prove Circulator Valve
Flame failure
A
Running
Excessive cabinet temperature
C
Running
Air flow sensor out of range
E
Running
Problem with air circulator fan
F
Running
Air heater limit stat
L
Running
Open air flow sensor
