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Munchkin 80M F09 error

thehustla Member Posts: 3
Hi All,

I have a Munchkin 80M unit that is getting a F09 error. Prior to getting this error, the fan inducer was replaced. After the fan was replaced, this error started to appear. Since then, we have replaced the burner with new gasket, both spark Spark Electrode and Flame Rectification Probe. Gas valve pressure has been tested. Flue is cleared. The unit does produce a spark but no flames. Tries 4 times before locking out.

Not sure what else can be looked at. The unit has the old Honeywell gas valve. I did purchase a new Dungs with the conversion kit but I suspect the valve is not the issue if it was working fine prior to changing the fan inducer.

Any recommendations?

I found a few threads to make sure condensation is not blocked and to make sure unit is grounded (assuming this is not the case since I am able to see a spark).


  • TomS
    TomS Member Posts: 60
    It sounds like you do not have gas flow through the gas valve. This is a negative pressure gas valve which requires the inducer to pull a vacuum on the outlet side of the valve in order to have gas flow. Since you changed the inducer check anything that would cause a lack of vacuum from being produced : inducer not spinning fast enough, leaky gaskets, disconnected or plugged hoses, etc.
    JUGHNE Member Posts: 10,278
    The grounding is more critical for the flame sensor to function.
    IIRC, you can monitor the flame rod current by setting the status menu to d7 while starting.
    If you get any reading at all the gas valve is opening but not enough flame to be recognized. Happens pretty fast.
  • HomerJSmith
    HomerJSmith Member Posts: 1,917
    edited November 2019
    I wrote about this so many times. You did plug in the two wire plugs in to the two sockets on the new blower?

    Did you replace the burner tube gasket and tighten down the 4 screws holding it tightly?

    You sanded the probes with wet and dry sandpaper, 100 grit?

    Is the gap on the spark probe the distance of two quarters placed together, about 1/4". If you need to widen the gap move the grounded probe lead and not the one that goes thru the ceramic.

    On the Honeywell gas valve, there is a brass nipple protruding out of the rear of the gas valve and this nipple sometimes touched the plastic case interfering with the gas valve functioning. You drill a 1/2" hole where the nipple touches the case thru the first wall of the case, not thru the whole case. So the nipple doesn't touch the case.