Modine Manufacturing PTC Installation And Service Manual page 29

servICe / mAInTenAnCe / TrouBlesHooTIng
Table 29.1 - Troubleshooting
TrouBle
unit does nothing
(verify green light on
side of junction box
is lit)
led light on ignition
controller in main
control compartment
off or flashing
unit starts but does
not ignite (verify green
and amber lights on side
of junction box are lit)
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. Multiple causes
1. Main gas is off
2. Air in gas line
3. Main or manifold gas pressure
4. Check gas valve switch
5. Clogged condensate drain line
6. Tripped limit switch on power
exhauster
1. Reversed main power polarity
2. Unit not grounded
3. Flame not sensed
1. Loose connections
2. Defective control board
3. Defective fan motor
PossIBle remedY
1. Turn on main power
2 a. Check control transformer
b. If failed transformer - check thermostat wire gage and length
3 a. Verify wire connections to R&W terminals only
b. Check / replace thermostat
4. Check LED flash code
5. Replace fuse
6. Replace control
1. Control board LED flash codes vary with control type. A decal is
installed in the unit giving a brief description of the applicable codes
for your heater. For more detail, see the control board data sheet
included with this manual.
1. Open manual gas valve
2. Purge gas line
3. Set gas pressures per manual instructions
4. Set gas valve switch to "ON" position
5. Check condensate drain line, clean as required
6. Inspect and reset limit switch if no unit damage found
1. Black wire - HOT, white wire - NEUTRAL, green wire - GROUND
2. Ground unit and verify quality of ground connection
3. Check flame sensing probe and connection
1. Check all connections
2. Check control board data sheet and function
3. Check fan motor
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