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Gas Input Rate
Table 12. Separated combustion tubular blower troubleshooting guide (continued)
SYMPTOMS
D. Floating flame.
E. Gas odor
F. Delayed ignition.
G. Failure to ignite.
H. Condensation.
I. Burners will not shut off.
J. Rapid burner cycling.
32
POSSIBLE CAUSE(S)
1. Blocked venting.
2. Insufficient combustion air.
3. Blocked heat exchanger.
4. Air leak into combustion chamber or flue
collector.
1. Gas leak. Shut off gas supply immediately!
2. Leaking gas test port on valve.
3. Blocked heat exchanger.
4. Blocked flue collector.
5. Negative pressure in the building.
1. Improper ground.
2. Bad or broken spark cable.
3. Faulty control.
4. Pressure regulator set too low.
5. Main burner orifices dirty.
6. Improper venting.
1. Gas leak. Shut off gas supply immediately!
2. No power supply to unit.
3. Thermostat not calling.
4. Defective high limit.
5. Defective draftor prove switch.
6. Defective spark ignitor, gas valve,
thermostat or transformer.
7. Loose wiring.
8. Improper ground.
9. Improper thermostat or transformer
wiring.
1. Improper venting.
2. Unit under fired.
3. Building/space too cold.
1. Thermostat located improperly.
2. Improper thermostat wiring.
3. Shorted circuit.
4. Defective thermostat.
5. Defective/sticking gas valve.
6. Defective control board.
7. 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. Thermostat located improperly.
CORRECTIVE ACTION
1. Clean flue. Refer to "Installation."
2. Clean combustion air inlet openings.
3. Clean heat exchanger. Refer to "Installation."
4. Determine leak and repair accordingly.
1. Inspect all gas piping and repair accordingly.
2. Check to ensure gas test ports are sealed.
3. Clean heat exchanger. Refer to "Installation."
4. Clean flue collector. Refer to "Installation."
5. See "Installation."
1. Check grounding wires and spark bracket
connections.
2. Inspect spark cable connections and cuts.
Replace if necessary.
3. Check to ensure spark is energized after pre-
purge period.
4. Test and reset manifold pressure.
5. Clean or replace orifices.
6. Refer to "Installation."
1. Open all manual valves, check for leaks.
2. Turn on power supply, check fuses and replace
if bad.
3. Turn up thermostat. Check for 24V on terminals
R and W1 on terminal strip.
4. Check switch for continuity if open with no heat
present; replace.
5. Check switch operation to ensure switch closes
after draftor purge period. If it does not make,
check tubing connections for blockage.
6. Check for continuity and voltage in safety and
control circuits; replace an item where
continuity or voltage not found.
7. Check all wiring per diagram.
8. Check all ground wires and connections.
9. Check both for wiring according to diagram;
check for 24V at gas valve terminals during trial
for ignition period. If present and valve does
not open, replace valve.
1. Refer to "Installation."
2. Check gas supply pressures to unit. Refer to
"Installation."
3. Refer to "Installation."
1. Relocate thermostat away from outside wall or
drafts.
2. Check thermostat circuit for open and close on
heater terminal strip "R" and "W."
3. Check thermostat circuit for shorts or any
staples piercing wires.
4. If thermostat is calling after set point has been
satisfied, replace.
5. Check for 24V on gas valve terminals when
thermostat not calling. Replace if necessary.
6. Check for 24V at terminals "R" and "W." If not
present and board is not in flash code mode,
replace board.
7. Refer to "Pipe Installation" and Table 4 - "Gas
Piping Requirements."
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 away from outside wall or
drafts.
GKNE-SVX001B-EN
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