Sterling GG-105 User Manual

35

  1. Relocate thermostat away from outside 

wall or drafts.

  2. Check thermostat circuit for open and close 

on terminal strip on heater “R” and “W”.

  3. Check thermostat circuit for shorts “staples 

piercing wires”.

  4. Check for 24v on gas valve terminals when 

thermostat is not calling.

 5. 

Refer 

to 

“Installation”.

  1. Tighten all electrical connections.
  2. Adjust heat anticipator setting for longer 

cycles. Refer to “Electrical Connections”.

  3. Check for proper air supply across heat 

exchanger and proper gas supply.

 4. 

 

Relocate thermostat.    

  
  1. Replace or tighten.
  2. Clean power venter wheel.
  3. Realign power venter wheel.

  1. Check and tighten wires on fan circuit.
  2. Test for 115v on terminal ACB Heat and 

“L2” if voltage is present replace motor.

  3. Test for 115v on terminal ACB Heat and 

“L2” on the control board, if voltage is not 
present 45 seconds after trial for ignition 
replace board.

 4. 

Replace 

fuse.

 1. Check motor amps against motor name 

plate, check voltage, replace if found defective.

  2. Check for 115v between motor leads.
  3. Check terminal ACB Heat for voltage if 

voltage not constant, replace board.

  1. Turn 115v power off to the unit, wait 10 

seconds and reapply voltage to the unit.

  2. Check wiring of fan circuit to wiring diagram.
   3. If unit is not calling for heat and board is not 

in a fl ash code mode, replace board.

 1. 

Refer 

to 

“Operation”.

  2. Is the heater output sized correctly for 

heat loss of the space. Has the space 
been enlarged?

  3. Check thermostat circuit, 24v on terminals 

“R” and “W” on terminal strip.

  4. Check air movement across heat exchanger. 

Check voltage and amps at the fan motor. 
Check gas input to ensure unit is not over 
fi red. Check heat exchanger to ensure unit 
is not dirty. 

   5. Check orifi ce size, replace if undersized.

  1. Refer to “Operation”. Check orifi ce size. 

If too big replace.

  2. Check thermostat for operation, to ensure 

circuit open and closes.

  3. Check wiring per diagram; check 

operation at the gas valve, look for 
a short in thermostat circuit.

  1. Refer to wiring diagram.
  2. Check grounding wires.
 3. 

Replace.

  1. Thermostat located incorrectly.

  2. Improper thermostat wiring.

 3. 

Shorted 

circuit.

  4. Defective sticking gas valve.

   5. Excessive gas supply pressure.

  1. Loose electrical connections at thermostat 

or gas valve.

  2. Excessive thermostat heat 

anticipator setting.

  3. Unit cycling on high limit.
  4. Poor thermostat location.

  1. Power venter wheel loose.
  2. Power venter wheel is dirty.
 3. 

Power venter wheel is rubbing on the housing.

 
  1. Loose electrical connections.
  2. Defective motor or overload.

  3. Defective control board.

 4. 

Blown 

fuse.

  1. Motor overload protection is tripping.

  2. Loose wiring or connection.
  3. Control board is defective.

  1. Control Board is in fl ame failure mode.

  2. Fan improperly wired.
 3. 

Defective 

board.

  1. Incorrect gas input.
 2. 

Heater 

undersized.

 3. 

Thermostat 

malfunction.

  4. Heater cycling on limit.

  5. Incorrect orifi ce size.

  1. Unit is over fi red.

 2. 

Thermostat 

malfunction.

  3. Heater runs continuously.

 1. 

Electrical 

short.

 2. 

Improper 

ground.

  3. Defective gas valve.

 

I. Burner will not shut off. 

 

J. Rapid burner cycling.

 

  K. Noisy power venter.

  L. Fan will not run.

  M. Fan motor turns on and off 

while burner is operating.

  N. Fan will not stop.

  O. Not enough heat.

 

P. Too much heat.

 Q. 

Blown 

fuse.