LAARS U.H.E. - Service Manual - Manual (Page 10)

LAARS Heating Systems Page 10
Refer to ignition module
illustration, is there 120VAC
between P1(1) and P1(3)?
Is front panel power
switch light on,
indicating power?
Y
N
Position front panel
power switch to
“ON” position.
Is there 120VAC
across switch?
(see photo at right)
Light burned out,
replace switch.
Y
Is there 120VAC
across terminal block?
(see photo at right)
N
Determine power source
problem and correct.
Repair/replace wire
harness to switch.
Y
N
Is ignition module
power light on?
N
Y
Refer to ignition module
illustration, is there 120VAC
going to module at locations
P7(1) and P7(3)?
N
Replace ignition module.
(see page 24)
Replace transformer.
(see page 35)
N N
Y Y
Is ignition module
power and flame light
flashing?
Reset heater by
interrupting power.
Reestablish power and
Adjust thermostat to
call for heat,
tank must be cold.
Allow heater to run
through heating cycle.
Did heater complete
heating cycle and did
blower post purge?
See next page
System is OK.
Supply voltage polarity is
incorrect.
Y
N
N
Y
Refer to ignition module
illustration, is there 24VAC
going to module at locations
P2(1) and P2(2)?
System Observation
IGNITION MODULE
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
10
Power Switch
Terminal Block
Replace ignition module.
(see page 24)