Troubleshooting - HeatStar HSU100NGPALP Operating Instructions And Owner's Manual

TROUBLESHOOTING

Symptom
Unit does not Start
LED Light Off or Flashing
Unit Starts but Does Not
Ignite
Unit Goes Through Cycle
but the Burners Go Out in
Less than 10 Seconds
Air Circulating Fan
Inoperable
Possible Cause
1. Power supply is off.
2. No 24V power to thermostat.
3. Thermostat malfunction.
4. LED flashes.
5. Blown fuse on control board.
6. Defective control.
1. Blown fuse on control board.
2. Multiple causes.
1. Main gas is off.
2. Air in gas line.
3. Main or manifold gas pressure.
4. Check gas valve switch.
1. Reversed main power polarity.
2. Unit not grounded.
3. Flame not sensed.
1. Loose Connections.
2. Defective control board.
3. Defective fan motor.
Compact Unit Heater
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6.
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4.
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17
Operating Instructions and Owner's Manual
Possible Remedy
Turn on main power.
Check control transformer.
a. If failed transformer – check
thermostat wire gage, length, and
defects.
Verify wire connections to R&W terminals
only.
a. Check/replace thermostat.
Check LED flash codes located on decal in
the unit or Table 10.
Replace fuse.
Replace control.
Replace fuse.
Control board LED flash codes vary with
control type. A decal is installed in the unit
and Table 10 gives a brief description of the
applicable codes for your heater.
1. Open manual gas valve.
Purge gas line following the necessary
precautions.
Set gas pressures per manual instructions.
Set gas valve switch to "ON" position.
Black wire – HOT, White Wire – NEUTRAL,
Green Wire – GROUND.
Ground unit and verify quality of ground
connection.
Check flame sensor probe and connection.
Check all connections.
Check control board data sheet and
function.
Check fan motor.