Munchkin 399M manual Servicing

SERVICING

F05 Supply Temperature is to High – This code appears if the Supply temperature sensor goes above 230 degrees.

Remedy – Let the Munchkin cool down, then manually push the reset button and see if the temperature increases to above 230 degrees. Determine if you have water flow or if the thermostat is continuously energized and correct the problem. Manually reset by pushing the S4/reset button.

F06 Return temperature is too High – This code comes if the return water temperature goes above 230 degrees,

Remedy – Let the Munchkin cool down then manually push the reset button and see if the temperature on the return increases to above 230 degrees. Check piping and determine the source of over heating and correct the problem. Manually reset by pushing the S4/reset button.

F09 This code will occur if the Munchkin control does not detect a flame. The Munchkin will make three attempts for ignition before the control will go into a lockout condition. The Munchkin control will try to re-ignite after one hour and continue to try to ignite every hour.

Remedy – Check the Flame Rod, Spark electrode or Hot Surface Igniter to see if they are in good condition, then clean it with abrasive paper and re-ignite. Also, check spark gap of ¼” on the spark electrode. If the Hot Surface igniter has any visible cracks, then replace it with a new Hot Surface Igniter. Check any flue blockage and condensate blocks. Also, check the Gas supply (Check Part 3, Table 1 [pg. 9] for pipe sizes and gas pressure settings) and correct problem if it is out of specification. The cleaning of the rectifier is recommended to provide a more consistent signal to the control. Manually reset by pushing the S4/reset button.

F10 This code appears if the flame is going out while the burner is on and this hap- pens more then 4 times in one heat demand.

Remedy – Check to see if the green light on your display is out while the unit is running. If the green light on the display either does not come on or goes out while running, read the flame rod with a voltage meter to read the flame current. If it’s less than 1 micro-amp, change or clean the flame rod. Also, check the Gas pressure while the unit is running to determine if pressure is adequate. See Part 3, Gas Connection. If the gas pressure is too low, correct the problem. Manually reset by pushing the S4/reset button.

F11 The flame detector circuit is seeing a flame signal while no flame is present.

Remedy – Check the wiring to the Gas Valve. Check the flame rod and make sure it’s clean, then manually reset S4/Reset button. If a lockout occurs, replace the board.

F13 Combustion fan running too slow. The speed detected of the hall pulse signal is less than 70% of the desired fan speed for longer then 1 minute.

Remedy – Check the Fan wiring. Manually reset by pushing the S4/reset button.

F14 The speed detected of the hall pulse is more then 130% of the desired fan speed for longer then 1 minute when the fan should be on. If the fan should be off and the speed detected of the hall pulse output is more then 1500rpm and longer then 1 minute, this code will appear.

Remedy – Check Fan Wiring. Manually reset by pushing the S4/reset button.

F18 Gas Valve not correctly connected/internal fault. Just before ignition, a test is per- formed on the gas connection. If there is a failure in the gas valve connection and or the valve is not connected, this fault code will appear.

Remedy – Check the connection to gas valve. Check the wiring to the board. If the problem persists, change gas valve cable. Manually reset by pushing the S4/reset .

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