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munchies at altitude?

How do the Munchkin boilers perform at altitude? I work in Steamboat Springs, Colorado. I would like to try a Munchkin but have little knowledge about them. I do radiant floor installations, p/s piping, and tekmar controls. How do the Munchkins compare?


  • Guy_5
    Guy_5 Member Posts: 159

    The Munchkin performs quite well at high altitude. It actually is available in a high altitude model for use with LP gas at elevations above 6000 feet. The natural gas units do not need any changes made. The primary difference with the HA unit is that it utilizes hot surface ignition, as opposed to spark.
    The unit is NOT de-rated by altitude. Because the air is less dense at altitude, the combustion blower has less restriction and therefore increases in RPM, delivering a constant CFM of air for combustion.
  • scrook_2
    scrook_2 Member Posts: 610

    even if constant *volume* (CFM) of air is delivered, because of lower density the fan delivers less *mass* (e.g. pounds per hour of air) which is what matters! The boiler may adjust for this however, I'm not familiar w/ the Munchkins, but that's another story. Check w/ Munchkin to be sure.
  • jim sokolovic
    jim sokolovic Member Posts: 439
    Derating at altitude

    I believe that until the National Fuel Gas Code is revised to consider premix burners and rpm controlled blowers, all gas-fired appliances must be derated 4 % per 1000 feet (over 2000 feet) above sea level. Most controls for this type of equipment regulate the rpm according to water temperature and within preset the rpm min. and max. limits. These boilers cannot differentiate what altitude they are at - therefore the rpm will not change at altitude, for the signals the control receives. The natural density change for each 1000 feet is about 3 %. I would imagine that these type of appliances will automatically derate by this much accordingly, close enough to satisfy the NFGC.
  • munchkin-man
    munchkin-man Member Posts: 247
    when ina high altitude area

    the boiler will not have to be derated however you will have to consider the caloric value / BTU's per cubic ft. from the gas supplier and sise the Munchkin acordingly.
  • John McArthur
    John McArthur Member Posts: 5

    Thanks for the info guys, I have a couple of heating jobs coming up that have very small mech rooms. I believe the Munchkin could be the answer. What control setups are used with p/s piping to make the most of the low temp return with regard to DHW. I know with radiant floor and outdoor reset that low temps are a bonus for efficiency, but do you guys use any particular DHW priority cotrols? I typically use tekmar, do the Munchies come with their own controls?
  • Ted_5
    Ted_5 Member Posts: 272
    Check out Viessmann Vitodens

    it is good to 10,000 ft. No changes or ajustments. It is also the most environmentally freindly boiler on the market
    94.2% AFUE NOx 8.9ppm CO 5.5ppm.

  • Dr. Heat
    Dr. Heat Member Posts: 11
    Munchies at alt

    I have 10 pre vision controll munchkins working at alt's above 7500'. I had all kinds of trouble with the only one on lp gas. Htp sent out all new controlls several times and it finnaly worked and is working well now. I am in Durango Colorado
  • Mark Eatherton1
    Mark Eatherton1 Member Posts: 2,542
    All condensing boilers at altitude...

    I've installed Muchkins and Vitoden$ at altitude, and what I've found is tha they do need to be derated for altitude, but not at the usual rate of 4% per thousand feet. I've found that derating them at 2% per thousnad feet works great. I've also "forced" them at altitude and got a butt load of CO as a result.

    With the Munchy, you'd best get certified to Vision 1 controls to utilize the full impact of the condensing capabilites.

    With the Vitodens, there's a 4 hour learning curve associated with the programming and check out of the controls, but the control is included as a part of the package.

    Both are good equipment, but the Vitoden$ is a lot heavier in all respects.


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