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UNIT HEATER
NO NO
Doe s pilot flame light ? Check gas supply and pilot Chec k if pilot flam e will light
gas pipe for blockage using a taper
YES YES
Check piezo igniter, lead
and ignition electrode for
damage. Replace as
necessary
NO NO
Does pilot flame remain On Wait 3 minutes Check that there is power to
Whe n st art button is rele ase d Try again .Button must be fully c oil terminals supplying the
on gas valve ? depressed in "start" position thermocouple interrupter
and held for at least 20 seconds relay.
a fter pilot flame ha s lit.
Test the thermocouple Change interrupter
output to the safety valve. relay
there should be 5 to 7 mV
between the thermocouple
sheath and the valve input
terminal
Change thermocouple
Burner Operating
8.3.2 Flame Supervision Systems - Manual Ignition
8.4 Fault Finding for Solenoid Valves
Note For manual ignition valves the gas will not
pass to the main burner until the pilot flame has
been lit and accepted and the valve knob has been
turned to main flame position.
Sta rt
NO
Test for 230v across valve Fault elsewhere
supply terminals at the Check all connections and
appropriate time controls including
lim it the rmostats
YES
NO
Test gas pressure at inlet of valve Fault elsewhere
Test gas pressure at outlet of valve. NO
Pressure should rise on outlet Solenoid valve faulty
when valve energises Replace as necessary
YES
Va lve Working
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