HOTSY • 900-1400 • 9.803-325.0-B OPERATOR MANUAL • GAS FIRED
23
PRESSURE
W
ASHER
Tr
oub
leshooting Guide
BURNER TROUBLESHOOTING
PROBLEM
POSSIBLE CAUSE
SOLUTION
HAVE PILOT FLAME,
MAIN BURNER WILL
NOT TURN ON
Faulty main valve coil in the
gas valve
Set test meter to 24 volt scale.
Faulty ignitor/sensor and/or its
wiring
With pilot flame on ignitor/sensor, probe terminals
MV and MV/PV on the ignition control unit. If
you read 24 volts here, but not at the gas valve,
there is a loose wiring connection. Repair or
replace as needed.
Ground wire not attached to
machine chassis
If you do read 24 volts at MV and MV/PV and the
pilot flame is impinging on the ignitor/sensor rod,
the problems may be:
Faulty ignition control unit
a. Faulty ignitor/sensor and/or its wiring.
b. Faulty ignition control unit.
Set test meter to the ohm scale. Turn burner
switch off.
Check continuity through the green ground wire
and its connections.
Reconnect the ignitor/sensor wire and the
ground wire.
Turn burner switch on. With the pilot burning and
the flame on the ignitor/sensor rod, the main burner
should turn on. If it does not, replace the ignition
control unit.
SHORT-CYCLING
OF MAIN BURNER.
MAIN BURNER
TURNS OFF
BEFORE THE
BURNER SWITCH
OR FLOW SWITCH
IS TURNED OFF
Draft condition pulls flame
from ignitor/sensor rod.
Check the thermostat by bypassing at terminals
P1 & 1.
Set thermostat high. With main burner on,
observe the pilot flame impingement on the
ignitor/sensor.
Faulty thermostat or water
temperature is too high
If pilot flame is small and draft condition pulls flame
from ignitor sensor rod, the burner will turn off and
then on again. a. Adjust pilot flame higher or clean
pilot oriface. b. Bend ignitor/sensor rod closer to
pilot flame.
If flame impingement on the ignitor/sensor is
stable and the system short-cycles, check the
limit switch.
Set test meter to 110 volt scale;
a. When the system cycles off, probe the switch
terminals of the limit switch.
b. If you read 24V accross the switch terminals
the limit switch is open. Replace the limit switch.
A pilot flame set too high will also cause burner
to short cycle. Pilot flame lifts over ignitor/sensor.
