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  1. #1
    Join Date
    Nov 2011
    Location
    Southwestern PA
    Posts
    28

    Confused Miller mobile home furnace

    Was out on a call today..No heat. Miller propane mobile home unit. Got there, it was a bit chilly inside. Has a hot surface ignitor on the burner. The draft inducer was running but no heat. I open the door to the furnace and it shuts off on the door switch...I toggle the switch and it starts the cycle. inducer, ignitor glows, gas comes on, lites off, warms up, fan comes on, satifies t-stat, burner shuts off, postpurge, blower shuts off. Cycle done.Gas pressure at 10.25'' W.C. out of the gas valve (a bit low) but gas valve has no press adjustment. Ignitor resistance at 80 ohms (even after being in a burner flame). I replaced the ignitor a few weeks ago with a glow fly. I wonder if the propane could have had a high moisture content and caused it not to light and trip out on saftey? It uses a honeywell S-369 control module I believe. Test run multiple times...No problem lighting off. This furnace uses (what I call) an inducer right under the burner to provide air for the fire. Any thoughts? I don't want to just swap out parts just to swap and hope i "found it". I even pulled the blower to check for a crack in the exchanger. Nothing of consequence...How old is this furnace? Model # CMF80-PO Serial # CMF9409-00442. It could be a 1994 furnace or it could be a 2009 furnace....

  2. #2
    Join Date
    Jul 2007
    Location
    Virginia
    Posts
    5,634
    Quote Originally Posted by red_oktober78765 View Post
    Model # CMF80-PO Serial # CMF9409-00442. It could be a 1994 furnace or it could be a 2009 furnace....
    Serial # CMF9409-00442

    94 = 1994

    09 = 9 month
    Instead of learning the tricks of the trade, learn the trade.

  3. #3
    Join Date
    Nov 2011
    Location
    Southwestern PA
    Posts
    28
    Thank you. Went back out since it is local after doing some thinking and looked on top of the propane tanks for a gauge....Wht did I find? NO GAUGE to tell me how much fuel is left in the tanks!!! Did some asking...Stove and furnace are propane and they last had the tanks filled about 3 months ago. These are two upright 100 gallon tanks I believe, or one is 100 and the other a 50, anyways, the tanks are trailer park owned as well as the home BUT are tennant responsible to get them filled. What a conundrum. Park needs to get a gauge on them so I know and the tennant knows how much are in the tanks and if the tennant is getting cheated by the supplier.

  4. #4
    Join Date
    Jan 2008
    Posts
    2,037
    I had problems when I tried a Glow Fly in a MH unit. Would light sometimes, sometimes not.
    I put in a spiral. No more problems.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  5. #5
    Join Date
    Nov 2011
    Location
    Southwestern PA
    Posts
    28
    It had a spiral ignitor in it when i went out on the origional service call. That one was a replacement at some time before me. It had the connector wire-nutted. When I tried to replace it with one of the same, mine hit the plate that is connected to the end of the burner (flame spreader) and promptly broke in half. I don't know how the tech that had that one on there got his to fit and work. used the glow fly and it fit pretty well.

  6. #6
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    i find the best solution is to tell them to buy a real house.

  7. #7
    Join Date
    Jan 2008
    Posts
    2,037
    I was replacing a spiral that would glow, but not ignite.
    As they wear out, they sometimes just aren't hot enough.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  8. #8
    Join Date
    Nov 2011
    Location
    Southwestern PA
    Posts
    28
    I am sorry...It wasn't a spiral. It was an "M" shaped with a rectangular, porcelian base, on the original service call.

  9. #9
    Join Date
    Nov 2011
    Location
    USA
    Posts
    385
    Quote Originally Posted by Gross View Post
    i find the best solution is to tell them to buy a real house.

  10. #10
    Join Date
    Dec 2007
    Posts
    4,711
    does the unit have a flame sensor rod also?
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  11. #11
    Join Date
    Dec 2010
    Location
    WV
    Posts
    115
    Quote Originally Posted by pacnw View Post
    does the unit have a flame sensor rod also?
    great ?.......does it lite a pilot flame? or lite burners? there must be some kind of flame sensor....and its probley a honeywell S-86 ignition module...just a guess....either way i hate the GlowFly....i use them only when i have too.....and if you have gas pressure at the valve then there is fuel to burn....100lb tanks do not have gauges installed.....if it were me i would find the factory ignitor...... a lot of the same style ignitors have different resistance values based on the brand.....meaning they glow either to soon or to late for proper lite off......had a rheem gave me a fit lighting, worked one day didnt the next....installed the factory ignitor and its still running....by looking they looked exactly the same......

  12. #12
    Join Date
    Dec 2007
    Posts
    4,711
    I have had ZERO issue with Glowflys as long as you follow the instructions!!!!!!

    company, 18 techs, have been using them for a couple years and no failures.

    I agree that the OEM igniter is the best.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  13. #13
    Join Date
    Nov 2011
    Location
    Southwestern PA
    Posts
    28
    I don't want to sound arguementative, but, my next door neighbor has the same size tanks on his propane furnace and his does have a gauge. How would the fuel delivery guy know how much he is putting into the tank? I believe on this system that the control module is using the resistance of the ignitor to sense the flame. No flame sensor rod is on this furnace. Don't think it ever had one from the factory. It uses the ignitor to ignite the main burner. No pilot.

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