12
21
CHECK FAN SELECTOR
SWITCH SETTING
SET FAN SELECTOR
SWITCH TO
AUTO
N
Y
IS
SWITCH SET
TO AUTO ?
CHECK SUMMER AIR
CIRCULATION
SWITCH
IS
SWITCH SET
TO OFF ?
DOES
FAN STILL
RUN ?
DOES
FAN STILL
RUN ?
SET FAN SUMMER
AIR CIRCULATION
SWITCH TO OFF
N
Y
Y
Y
DOES
FAN STILL
RUN ?
DISCONNECT AIRFLOW
SENSOR
Y
DOES
FAN STILL
RUN ?
REPLACE
ELECTRONICS
MODULE
Y
IS
PILOT FLAME
TOO
BIG?
N
Y
ADJUST PILOT
FLAME TO CORRECT
SETTING
REPLACE
AIRFLOW SENSOR
N
FAN CONTINUES TO RUN AFTER HEATING IS TURNED OFF
8.
MAINTENANCE
IMPORTANT: Ensure that the gas and electricity supplies are isolated before commencing any maintenance or replacement of
components. 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 Sect 6.1 to 6.8 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 debris, remove and clean the Air Circulation fan as detailed at S 8.8.
8.1.5
Remove the Burner and Controls Assembly as detailed in para 8.2. 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 pilot 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 Light the appliance and note the main burner flame profile. If the flame profile is affected when the Air Circulation fan
switches on, check for any air leaks between the air heater and the base plenum, paying particular attention to heaters
with rear draught diverters. Rectify any air leaks before continuing with this procedure.
8.1.12 Allow the air heater to operate for approximately 15 minutes to ensure stability and, with the main burner lit, ensure
that the operation of Air Circulation fan does not affect the main burner flame profile.
8.2
BURNER AND CONTROL ASSEMBLY REMOVAL:
8.2.1
Ensure that the Gas and Electrical supplies are switched OFF
8.2.2
Remove the appliance lower front door.
8.2.3
Disconnect the igniter at the Piezo unit.
8.2.4
Disconnect the Multifunctional Control electrical connection.
8.2.5
Disconnect the water heater (if necessary).
8.2.6
Disconnect the gas supply by breaking the union at the input side of the Multifunctional Control.
8.2.7
Remove 6 x Burner Assembly fixing screws and withdraw the Burner Assembly.
8.2.8
Refit the Burner and Control Assembly in reverse order, ensuring that the spillage baffle above the Burner Assembly
contacts the top of each burner arm.
8.3
MAIN BURNER ASSEMBLY CLEANING:
8.3.1
Remove the Burner and Control Assembly as detailed in 8.2.
8.3.2
Clean the burner thoroughly both inside and out with a soft brush.
DO NOT ENLARGE, DISTORT OR DAMAGE
BURNER HOLES.
8.3.3
Reassemble in reverse order.
8.4
MAIN INJECTORS REMOVAL, CLEANING AND REPLACEMENT:
8.4.1
Remove the Burner and Control Assembly as details in 8.2
8.4.2
Remove 2 x screws securing the Pilot Burner assembly to the Burner and Control Assembly and withdraw the Pilot
Burner assembly, taking care to avoid damage to the thermocouple capillary.
8.4.3
Remove 2 x screws securing the Burner arm to the Burner and Controls Assembly, and withdraw the Burner Arm.
8.4.4
Unscrew 2 x Main injectors, and 1 x cross lighter injector from their housings.
8.4.5
Clean as necessary.
DO NOT ENLARGE, DISTORT OR DAMAGE MAIN INJECTOR HOLES.
8.4.6
If the injectors are to be replaced, ensure that they are correctly marked, referring to the Data Badge for details.
8.4.7
Refit or replace the injectors in reverse order.
