Johnson & Starley 42-451-15, Installation, Commissioning & Servicing Instructions

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8.5
PILOT BURNER, THERMOCOUPLE AND ELECTRODE, REMOVAL AND REPLACEMENT:
8.5.1 Remove the Burner and Controls Assembly as detailed in 8.2
8.5.2 Disconnect the Igniter Lead from the Piezo Unit.
8.5.3 Disconnect the Thermocouple from the Thermocouple Adapter on the Multifunctional Control, taking care to
avoid damage to the Thermocouple Capillary.
8.5.4 Release the Pilot Feed Pipe from the Multifunctional Control.
8.5.5 Remove 2 x 4mm screws securing the Pilot Burner Assembly to the Burner Arm, and withdraw the Pilot Burner
Assembly.
8.5.6 Release the Thermocouple securing nut from the Pilot Burner Assembly and withdraw the Thermocouple, taking
care to avoid damage to the Thermocouple Capillary.
8.5.7 Release the Electrode securing nut from the Pilot Burner Assembly and withdraw the Electrode.
8.5.8 Release the Pilot Feed Pipe securing nut from the Pilot Burner Assembly and withdraw the Pilot Feed Pipe and
Pilot Injector from the Pilot Burner Assembly, and disconnect the Pilot Injector from the Pilot Feed Pipe hook.
8.5.9 Release the 2 x 5mm screws securing the Pilot Burner Bracket to the Pilot Mounting bracket, and remove the
Pilot Burner Bracket.
8.5.10 Refitting or replacement is in reverse order.
NOTE: When refitting or replacing the Thermocouple, tighten only to FINGER TIGHT + 1 FLAT.
8.6 MULTIFUNCTIONAL CONTROL REMOVAL:
8.6.1 Remove the Burner and Controls Assembly as detailed in 8.2
8.6.2 Disconnect the Thermocouple at the Multifunctional Control including the adapter, avoiding damage to the
capillary.
8.6.3 Disconnect the Pilot Feed Pipe from the Multifunctional Control.
8.6.4 Disconnect the Multifunctional Control input and output supply feeds.
8.6.5 Refitting or replacement is in reverse order.
8.7
PIEZO UNIT REMOVAL:
8.7.1 Disconnect the 2 x conductors from the Piezo unit.
8.7.2 Unscrew the Piezo retaining nut and remove the unit from its mounting bracket.
8.7.3 Refitting or replacement is in reverse order.
8.8 AIR CIRCULATING FAN, REMOVAL AND CLEANING:
8.8.1 Ensure that the electrical supply is isolated.
8.8.2 Remove the Air Filter and air heater cabinet doors.
8.8.3 Disconnect the Overheat Limit Device at the terminal block plug situated on the right hand side of the fan
chamber floor.
8.8.4 Disconnect the 230V connections (L/N/E) from the Fan Assembly.
8.8.5 Release the 2 x Fan Assembly securing screws and withdraw the Fan Assembly from the Heater cabinet.
8.8.6 Refitting is in reverse order.
8.9 ELECTRICAL ASSEMBLY REMOVAL:
8.9.1 Ensure that the electrical supply is isolated.
8.9.2 Remove the appliance lower and upper doors.
8.9.3 Release the 2 x 4mm screws securing the Limit Switch cover and withdraw the cover.
8.9.4 Release the 2 x Electrical Assembly cable clamps,
MODAIRFLOW models:
8.9.5 Disconnect the following
a. 230V connections (L/N/E) from the Fan Assembly,
b. 230V mains ‘ L ’, ‘ N ’ and ‘ E ’ from connection block terminals ‘ 1 ’, ‘ 3 ’ and ‘ 2 ’ respectively,
c. Thermista-stat connections from connection block terminals ‘ 4 ’ (+ve) and ‘ 5 ’ (-ve),
d. Overheat limit control ‘ LOAD ’ and ‘ COMMON ’ connections,
e. 2 x Airflow Sensor connections,
9. DEFECT DIAGNOSIS
9.1
IMPORTANT: If an electrical defect occurs after installation of the appliance; preliminary earth continuity,
polarity, and resistance to earth checks should be carried out with a multimeter. On completion of any
maintenance/fault-finding task that has required the breaking and remaking of electrical connections, then
checks of continuity, polarity, and resistance to earth must be repeated.
9.2 WARNINGS:
9.2.1 When purging or checking gas supplies, ensure that the ventilation to the room or cupboard is adequate, and that
all naked lights are extinguished.
9.2.2 MODAIRFLOW models: Before commencing defect diagnosis, ensure that the Thermista-stat is set to
maximum, the mains supply is ‘ON’ and the time control is at an ‘ON’ position.
9.2.3 Care is to be taken during the replacement and handling of electronic assemblies (i.e. electronic panel, airflow
sensor or Thermista-stat), it is not practical to rectify defects on these assemblies, except at the manufacturer,
and any attempt to do so may render the guarantee or factory replacement arrangement invalid.
SYMPTOM POSSIBLE CAUSE REMEDY
a. Pilot will not light. i. No gas supply to heater. Check for gas at inlet pressure test
point on Multifunctional Control.
ii. Gas supply pipe not purged. Purge gas supply pipe in accordance
with BS 6891.
iii Pilot orifice restricted. Clear pilot orifice or replace pilot injector.
iv. Piezo system faulty. Check igniter, lead, and electrode.
v. Excessive gas supply pressure. Check that mains gas pressure is 20mbar,
and reduce if necessary.
b. Pilot lights but goes i. Connection between thermo- Check connection is secure.
out on releasing START couple and Multifunctional
button during initial Control not secure.
light-up, or after
normal operation. ii. Faulty power unit on Replace Multifunctional Control.
Multifunctional Control.
iii. Faulty thermocouple. Replace Thermocouple.
c. Main burner lights i. Loose electrical connection Check connections.
but fan fails to run Fan Delay Control.
after approx. 3 min.
ii. Fan Delay Control set incorrectly. Check for correct settings.
iii. Faulty fan assembly. Replace, taking care not to damage
impeller.
iv. Faulty fan delay control. Replace.
d. Main burner opera- i. Gas rate or burner pressure Check gas rate and burner pressure
ting intermittently setting high. setting.
with fan running.
ii. Temperature rise excessive. Adjust fan speed or gas rate accordingly.
iii. Air filter or return air path Check filter is clean and air path is clear.
restricted.
iv. Excessive number of outlets Open additional outlets.
closed.
v. Spillage of flue gases. Carry out spillage test and rectify.
vi. Spillage monitor device (TTB) Replace Spillage device (TTB)
faulty.
e. Main burner opera- i. Gas rate or burner pressure Check gas rate and burner pressure
ting with intermittent setting too low. setting.
fan operation.
ii. Fan Delay Control set incorrectly. Check for correct settings.
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9. DEFECT DIAGNOSIS