Installation and Maintenance Manual

Diagnostics
GKND-SVX01B-EN 39
2. Pilot adjustment screw turned too
low on combination/automatic
main gas valve.
2. Refer to “Operation,” p. 27.
3. Air in gas line. 3. Purge air from gas supply.
4. Incorrect lighting procedure. 4. Follow lighting instruction label adjacent to gas valve.
5. Dirt in pilot orifice. 5. Remove pilot orifice. Clean with compressed air or solvent.
(Do not ream.)
6. Extremely high or low gas
pressure.
6. Refer to “Operation,” p. 27.
7. Drafts around unit. 7. Eliminate drafts. Refer to “Installation: Mechanical,” p. 12.
8. Pilot valve not opening (faulty
wiring).
8. Inspect and correct all wiring.
9. No spark (faulty wiring). 9. Inspect and correct ignition system wiring. See symptoms
U, V, and W.
10. Defective gas valve. 10. Replace.
N. Fan will not run. 1. Loose wiring. 1. Check and tighten all wiring connections per diagrams.
Thermostat wires tagged “W” and “G” must be connected
together (unless special thermostats are used; if so, see
thermostat wiring diagram, “Electrical Connections,” p. 24).
2. Defective motor overload
protector or defective motor.
2. Replace motor.
3. Defective fan switch. 3. Check for 24V across 1 and 3 terminals on fan time delay
switch. If 24V is present, jumper terminals numbered 2 and
4. If motor runs, the fan switch is defective and must be
replaced. If 24V is not present, check wiring per diagrams.
O. Fan motor turns on and off while
burner is operating.
1. Fan switch heater element
improperly wired.
1. Be sure fan switch heater terminals are connected per
diagrams.
2. Defective fan switch. 2. Replace fan switch.
3. Motor overload protector cycling
on and off.
3. Check motor amps against motor name plate rating, check
voltage, replace fan motor if defective.
4. Motor not properly oiled. 4. Refer to label on motor.
P. Fan motor will not stop. 1. Improperly wired fan control. 1. Check all wiring.
2. Main burners not lighting while
thermostat calls for heat.
2. Refer to H and N symptoms.
3. Defective fan switch. 3. Replace fan switch.
Q. Not enough heat. 1. Incorrect gas input. 1. Refer to “Operation,” p. 27.
2. Heater undersized. 2. This is especially true when the heated space is enlarged.
Have the heat loss calculated and compare to the heater
output (80 percent of input). Your gas supplier or installer
can furnish this information. If heater is undersized, add
additional heaters.
3. Thermostat malfunction. 3. Replace thermostat.
4. Heater cycling on limit control. 4. There should be NO ducts attached to the front of this
heater. Check air movement through heat exchanger. Check
voltage to fan motor. Clean fan blade and heat exchanger
and oil fan motor.
R. Too much heat. 1. Thermostat malfunction. 1. Replace thermostat.
2. Heater runs continuously. 2. Check wiring per diagrams; check operation at valve. Look
for short (such as staples piercing thermostat wiring), and
correct; replace gas valve. Refer to “Operation,” p. 27.
S. Cold air is delivered on start up. 1. Fan switch heater element
improperly wired.
1. Be sure fan switch heater terminals are connected per
diagrams.
T. Cold air is delivered during heater
operation.
1. Incorrect manifold pressure or
input.
1. Refer to “Operation,” p. 27.
2. Voltage to unit too high. 2. Check motor voltage with fan running. Should be 115 volts
AC.
3. Air throughput too high. 3. Refer to “Operation,” p. 27.
Table 7. Troubleshooting guide (continued)
Symptoms Possible Cause(s) Corrective Action