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Munchkin Boilers and Propane

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hr Member Posts: 6,106
in THE MAIN WALL
I have seen that exact compound in several mod cons also. One was drawing air from above a gravel parking lot. Right under the roof eve but 15 feet up.

I think it has to do with the fuel and the quality of the intake air.

I still feel they should have optional air filters for some locations. A large washable type of cleaner.

Regardless, this would just move the problem to another, but easier to service location.

I really feel ALL mod cons should have a yearly HX cleaning and maintenance. I imagine a partially plugged HX starts to cut into the efficiency numbers.

Also this is not a brand specfic issue.

hot rod

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Comments

  • Gary Bosley
    Gary Bosley Member Posts: 1
    Munchkins and Propane

    We have a contractor who has installed two Munchkin 399 high efficiency boilers in a church. The boilers are fueled with propane. We can not keep them clean. The heat exchangers become coated with a metallic coffee ground like substance and this eventually clogs the condensate drain amongst other problems. Munchkin has looked at the installaion, set up the boilers and installed a fuel filter on the incoming line. None of this has helped. Has anyone else had this problem and is there a solution. Any input would be greatly appreciated. Thanks
  • Rob L_3
    Rob L_3 Member Posts: 25
    Look at Venting and Condensate Drain

    Hi Gary,
    I saw what you describe several years ago in one of our system installations. These boilers were the 199 Munchkins.
    I dont know if our installations are similar but here is what we found and did.
    First thing we found was that the boilers were possibly recirculating the flue gases and it eventually solidified inside the heat exchanger. We extended the flue pipe up a few feet. We also found that the air gap on the hose barb that connected to the drain hose was clogged or partially covered by hose. We pulled the hose back and drilled out the plugged air gaps. I dont think it has been a major problem since. The customer cleans and flushes 2x a year.
    You may also want to consider a condensate pump for these boilers.

    Hope some this helps.

    Rob L
  • Art_5
    Art_5 Member Posts: 1
    Munchkin

    Are the deposits causing the condensate hose to block or visa versa? There are those who would place a 90 degree hose barb fitting in place of the straight one supplied and dump that into a 3/4" PVC Pipe with air space all around it.
  • Garritt
    Garritt Member Posts: 27
    Munchkin and Propane

    Of the many munchkins we have installed, we have the most problems with propane fuel rather than natural gas. On the west cost, our natural gas is pretty clean (as opposed to other parts of the country). Our problem is that when we go to do a combustion test on the munchkin, our readings change considerably when the homeowner gets another load of fuel. We usually shoot for our combustion analyzer to read a Carbon Monoxide of 115 ppm on high fire instead of 80-150 ppm like the book says. This sets the combustion setting to the middle of the range.

    We've had so many problems with the propane driven munchkin that we are STRONGLY thinking of going with the lochinvar Effeciency boiler. It has 2 stages of firing, and it's atmospheric so we won't have any combustion problems. Just something for you munchkin guys at the factory to think about.

    PexRunner
  • Kevin O. Pulver
    Kevin O. Pulver Member Posts: 380
    Regarding clean air...

    Is this why the latest Rinnai water heater I installed had a re-designed flue pipe termination withhe flue extended about a foot further than the intake?
    It looks a little ugly compared to the old, but I figured that was the reason for it. The optional isolation/flush valves/union kit is also upgraded it's the fancy Watts that I see in the Jobsite mag all the time. NICE!
    Kevin
  • Chris Tall
    Chris Tall Member Posts: 1
    Dirty Little Munchkins

    Hi Gary,

    I just had the same problem. I have a 399M in a commercial application. It is used very little as we have 2 pellet boilers for the heating season. The Munchkin is for Heating and DHW backup.

    It started to have F10 (or E10) errors. We thought it was the gas supply and so we spent a couple weeks chasing that down. Eventually I opened the chamber and was surprised to find a small rock quarry and green patches all over the tubes.

    Going by the dealer and the manual, I purchased some CLR and went at it. I am now waiting for my local favorite Wet Head to stop by so I can check the exhaust gases and see if that helped.

    PS I have pics of the inside if you want to match up for comparison.
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