Burner Troubleshooting - Hotsy 1.109-691.0 Dealer's Manual

Maintenance

Burner Troubleshooting

PROBLEM
HAVE PILOT FLAME,
MAIN BURNER WILL
NOT TURN ON
SHORT-CYCLING
OF MAIN BURNER.
MAIN BURNER
TURNS OFF BEFORE
THE BURNER SWITCH
OR FLOW SWITCH
IS TURNED OFF
28
POSSIBLE CAUSE
Faulty main valve coil in the
gas valve
Faulty igniter/sensor and/or its
wiring
Ground wire not attached to
machine chassis
Faulty ignition control unit
Draft condition pulls flame from
igniter/sensor rod.
Faulty thermostat or water
temperature is too high
Hotsy 900/1400 Series Dealer Manual 9.803-324.0 - AW
SOLUTION
Set test meter to 24 volt scale.
With pilot flame on igniter/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.
If you do read 24 volts at MV and MV/PV and the pilot
flame is impinging on the igniter/sensor rod, the
problems may be:
a. Faulty igniter/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 igniter/sensor wire and the ground
wire.
Turn burner switch on. With the pilot burning and the
flame on the igniter/sensor rod, the main burner
should turn on. If it does not, replace the ignition
control unit.
Check the thermostat by bypassing at terminals P1 &
1.
Set thermostat high. With main burner on, observe
the pilot flame impingement on the igniter/sensor.
If pilot flame is small and draft condition pulls flame
from igniter sensor rod, the burner will turn off and
then on again. a. Adjust pilot flame higher or clean
pilot orifice. b. Bend igniter/sensor rod closer to pilot
flame.
If flame impingement on the igniter/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 across 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 igniter/sensor.