Jupiter Heating.com

Directory: Catalog > Boilers > Munchkin Boilers > Munchkin Parts

Munchkin Control Board Fault Codes

Below are the common error codes associated with a 925 or 926 control board. Some codes and remedies may vary slightly depending on model and version.

 

Code Description Remedy
E00 High Limit Exceeded
Duration: 50 sec.
  1. Check circulation pump operation.
  2. Assure there is adequate flow through the boiler by accessing the status menu and assuring there is less than a 50°F rise from the return thermistor to the supply thermistor.
E13 Combustion Fan Speed Low –
The boiler combustion air fan speed less than 70% of expected.
Duration: 60 sec.
  1. Check the combustion air fan wiring.
  2. Replace the combustion blower motor.
  3. Replace the control board.
E14 Combustion Fan Speed High –
The boiler combustion air fan speed is more than 130% of expected.
Duration: 60 sec.
  1. Check the combustion air fan wiring.
  2. Replace the combustion blower motor.
  3. Replace the control board.
F00 High Limit Exceeded.
  1. Check circulation pump operation
  2. Assure that there is adequate flow through the boiler by accessing the status menu and assuring that there is less than a 50°F rise from the return thermister to the supply thermister.
  3. Check thermister reading on supply thermister. Replace switch if faulty.
F01 Vent Temperature Limit Exceeded.
  1. Push the red reset button on the switch.
  2. Check the flue temperature during operation using a combustion analyzer.
  3. Replace the switch if faulty.
F02 Interrupted or Shorted Supply (Outlet) Thermister.
  1. Check the electrical connection to the thermister on the outlet manifold.
  2. Replace thermister if necessary.
F03 Interrupted or Shorted Return (Inlet) Thermister.
  1. Check the electrical connection to the thermister on the inlet manifold.
  2. Replace thermister if necessary.
F05 Supply (Outlet) Temperature exceeds 230°F.
  1. Check circulation pump operation.
  2. Assure that there is adequate flow through the boiler by accessing the status menu and assuring that there is less than a 50°F rise from the return thermister to the supply thermister.
F06 Return (Inlet) Temperature Exceeded 230°F.
  1. Check circulation pump operation.
  2. Assure that there is adequate flow through the boiler by accessing the status menu and assuring that there is less than a 50°F rise from the return thermister to the supply thermister.
F09 No flame detected –
The boiler will make three attempts at ignition before the control goes into this lockout condition.
  1. Watch the spark electrode through the observation window provided.
  2. If there is no spark, check the spark electrode for the proper ¼” gap.
  3. Remove any corrosion from the spark electrode and flame rectification probe.
  4. If there is a spark but no flame, check the gas supply to the boiler.
  5. If there is a flame, check the flame sensor.
  6. Check any flue blockage or condensate blocks.
F10 Loss of Flame Signal –
The boiler will relight 4 times before the control goes into this lockout condition.
  1. Monitor the gas pressure to the unit while in operation.
  2. Assure that the flame is stable when lit.
  3. Check to see if the green light on the display module is out while the boiler is running.
  4. If the green light doesn’t come on or goes off during operation check the flame signal on the status menu.
  5. If the signal reads less than 1 microampere, clean the flame rectification probe.
  6. If the flame rectification probe continues to read low, replace it.
F11 False Flame Signal –
The boiler will lock out if it senses a flame signal when there should be none present.
  1. Turn the gas off to the unit at the service valve.
  2. If the flame signal is still present replace the spark electrode.
  3. If the flame signal is not present after turning off the gas supply, check the gas valve electrical connection.
  4. If there is no power to the gas valve, remove the valve and check for obstruction in the valve seat or replace the gas valve.
  5. Turn the gas on at the service valve after corrective action is taken.
F13 Combustion Fan Speed Low –
The boiler will lock out if it senses that the fan speed is less than 70%of expected rate formore than 60 seconds.
  1. Check the combustion air fan wiring.
  2. Replace the combustion blower motor.
  3. Replace the control board.
F14 Combustion Fan Speed High –
The boiler will lock out if the fan speed is more than 130%of expected rate for more than 60 seconds.
  1. Check the combustion air fan wiring.
  2. Replace the combustion blower motor.
  3. Replace the control board.
F18 Gas Valve Error
  1. Make sure the connector is correctly connected to the gas valve.
  2. Check the electrical wiring from the valve to the control board.
  3. Replace the low voltage wiring harness assembly.
  4. Replace control board.
F30 Watchdog Call factory for further assistance.
F31 Parameter Memory Call factory for further assistance.
F32 Parameter Memory Write Error Call factory for further assistance.
F33 Programming Error Call factory for further assistance.
PRO Water Pressure Switch is Open
Duration: Until Corrected
  1. Assure that the system pressure is above 10 psig.
  2. Check for leaks in the system piping.
FLU Blocked Vent Pressure Switch is Open
Duration: Until Corrected
  1. Check the flue vent to be sure it is not blocked or damaged.
  2. Check the Blocked Vent Pressure Switch operation by applying a jumper.
  3. If the switch is not functioning properly, replace it.
  4. If your unit has a Blocked Vent Pressure Switch, DO NOT permanently "jump out" this part. The switch ensures safety and must be operational at all times of normal operation. Jumper wire is only for units that DO NOT have a Blocked Vent Pressure Switch.
FLU
(with new board)
For New 926 Board Installation
  1. When a new 926 control board is programmed, the default setting is "with Flue Switch." For early Munchkin units without a Blocked Vent Pressure Switch, this will trigger a FLU error because the switch is not present. Therefore, permanently use the red jumper wire to jump this function.
  2. Not sure if you have this switch? Locate pink wires in position 9 of the 10-pin X8 molex connector, and position 19 of the 20-pin X4 molex connector. If pink wires are present, they lead to the Blocked Vent Pressure Switch. However, if pink wires are not present, the Blocked Vent Pressure Switch was not installed on unit. The jumper will be needed to bypass the FLU error.
  3. After the jumper is installed, the reset button must be pressed on the display to clear the error code. Clearing the code indicates that the jumper wire was sucessfully installed.
  4. See Munchkin Control Board Wiring Diagram for location of the Blocked Vent Pressure Switch.