LAARS U.H.E. - Service Manual - Manual (Page 14)

LAARS Heating Systems Page 14
Refer to ignition module
illustration, Is there 120VAC
between P1(1) and P1(3)?
Refer to ignition module
illustration, Is there
22 - 27VAC between
P2(1) and P2(2)?
Refer to ignition module
illustration, Is there 120VAC
between P7(3) and P7(1)?
Replace transformer.
(see page 35)
Refer to ignition module
illustration, Is there 24VAC
between P3(9) and P2(1).
N
N
Y
Y
Check wire harness
continuity. Replace
thermostat sensor or wire
harness as necessary.
(see page 17)
Check AC source to
determine why there is no
power.
Replace
ignition module.
(see page 34)
N
Check continuity through
ECO, red wires of
thermostat sensor.
Check at temperature
less than 160°F
Is there continuity?
(see photo at right)
N
Replace ignition module.
(see page 34)
Y
Replace thermostat
circuit board.
(see page 15)
Y
N
Y
IGNITION MODULE
Thermostat circuit.
(continued from page 12)
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
14
Red Wires
(Temperature Sensor)