Service & Troubleshooting - Modine Manufacturing IFS Installation And Service Manual

SERVICE & TROUBLESHOOTING
Table 24.1 - Troubleshooting
Trouble
Power Exhauster Motor will not start
Pilot does not light
Main burners do not light (Pilot is lit)
Lifting Flames (See Figure 25.1)
Yellow Tipping
(With propane gas, some yellow tipping is
always present.)
Flashback
Floating Flames (See Figure 25.2)
Flame Rollout (See Figure 25.3)
24
Possible Cause
1. Power supply is off.
2. No 24V power to thermostat.
3. Thermostat malfunction.
4. Defective power exhauster relay.
5. Defective power exhauster motor.
1. Main gas is off.
2.
Power supply is off.
3. Air in gas line.
4. Dirt in pilot orifice.
5. Gas pressure out of proper range.
6. Pilot valve does not open.
a. Defective ignition controller.
b. Defective gas valve.
7. No Spark at ignitor.
a. Loose wire connections.
b. Pilot sensor is grounded.
c. Defective ignition controller.
8. Safety device has cut power.
1. Defective valve.
2. Loose wiring.
3. Defective pilot sensor
4. Defective ignition controller.
5.
Improper thermostat wiring.
1. Too much primary air.
2. Main pressure set too high.
3. Orifice too large.
1. Insufficient primary air.
2. Dirty orifice.
3. Misaligned orifice.
1.
Too much primary air.
2. Main pressure set too high.
3. Orifice too large
1. Insufficient primary air.
2. Main pressure set too high.
3. Orifice too large.
4. Blocked vent.
1. Main pressure set too high.
2. Orifice too large.
3. Blocked vent.
AIR 5-593.9
Possible Remedy
1. Turn on main power.
2. Check control transformer.
3. Check/replace thermostat.
4. Replace power exhauster relay.
5. Replace power exhauster motor.
1. Open manual gas valve.
2.
Turn on main power.
3. Purge gas line.
4. Check for plugged pilot orifice and clean
with compressed air if necessary.
5. Adjust to a maximum of 14" W.C.
Minimum for Natural Gas - 6" W.C.
Minimum for Propane Gas - 11" W.C.
6. Check wiring for 24 volts to valve.
a. Replace ignition controller.
b. Replace gas valve.
7.
a. Check all ignition controller wiring.
b. Replace sensor if cracked or worn
c. Replace ignition controller.
8. Check all safety devices (High limit, air
flow proving switch, differential pressure
switch, gas pressure switches, etc.)
Determine and correct problem. Reset
if necessary.
1. Replace valve.
2. Check wiring to gas valve.
3. Replace pilot sensor.
4. Replace ignition controller.
5.
Verify wiring compared to wiring diagram.
1. Reduce primary air.
2. Adjust to a maximum of 14" W.C.
3. Check orifice size with those listed on
the serial plate.
1. Increase primary air.
2. Check orifices and clean with
compressed air if necessary.
3. Check manifold, replace if necessary.
1.
Reduce primary air.
2. Adjust to a maximum of 14" W.C.
3. Check orifice size with those listed on
the serial plate.
1. Increase primary air.
2.
Adjust to a maximum of 14" W.C.
3. Check orifice size with those listed on
the serial plate.
4. Clean/correct venting system.
1. Adjust to a maximum of 14" W.C.
2.
Check orifice size with those listed on
the serial plate.
3. Clean/correct venting system.