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  1. #1
    Join Date
    Apr 2011
    Location
    michigan
    Posts
    172

    Cozy DV Space Heater Thermopile problem

    I Have a customer with a Cozy brand direct vent space heater that will only work for about 2 weeks until the thermopile has to be replaced. I believe the gas control is bad but have not been able to prove it as of yet. Both times I have went back the pilot will not stay lit, yet the old thermopile was still genetrating 300 to 450 milivolts. I replace the thermopile with a new one which generates 800 milivolts when new and the heater works fine. I believe the gas control is faulty but want to prove it before spending 150.00 on a new control. I also know this unit has had problems in the past before I worked on it, but I am unable to find out what has been done in the past as there was a different person living at the place then. Does anyone have any suggestions? I believe the control is a robert shaw it has no info on it to tell for sure. I have removed the thermostat from the circut an tested the operation and it does not seem to matter, when the main valve is energized my milivolt signal drops to between 230 and 250 milivolts and when I open the main valve knob and allow the burner to light the pilot signal goes up to around 330 milivolts.

  2. #2
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    5,599
    Thermopiles/couples usually fail due to overheating. Sometimes someone will stick something in the pilot orifice and enlarge the hole.
    I once counted over 30 thermocouples hanging on a basement wall. All had failed. I removed the pilot and saw the large hole in the orifice. Someone couldn't keep the pilot lit because of incorrect secondary air adjustment so they made a bigger pilot.
    Tracers work both ways.

  3. #3
    Join Date
    Jul 2001
    Location
    Central MN and the Twin Cities
    Posts
    1,530
    Is it on nat. gas or L.P.?
    Warning: Just because I am over the head injury doesn't mean I'm normal!

    The day I stop learning.... I'm dead!

  4. #4
    Join Date
    Feb 2004
    Posts
    2,463
    Quote Originally Posted by Toddbrewster View Post
    I Have a customer with a Cozy brand direct vent space heater that will only work for about 2 weeks until the thermopile has to be replaced. I believe the gas control is bad but have not been able to prove it as of yet. Both times I have went back the pilot will not stay lit, yet the old thermopile was still genetrating 300 to 450 milivolts. I replace the thermopile with a new one which generates 800 milivolts when new and the heater works fine. I believe the gas control is faulty but want to prove it before spending 150.00 on a new control. I also know this unit has had problems in the past before I worked on it, but I am unable to find out what has been done in the past as there was a different person living at the place then. Does anyone have any suggestions? I believe the control is a robert shaw it has no info on it to tell for sure. I have removed the thermostat from the circut an tested the operation and it does not seem to matter, when the main valve is energized my milivolt signal drops to between 230 and 250 milivolts and when I open the main valve knob and allow the burner to light the pilot signal goes up to around 330 milivolts.
    What is the dropout read??

  5. #5
    Join Date
    Apr 2011
    Location
    michigan
    Posts
    172
    This heater is Lp gas . The pilot orfice and assembly are both brand new as i replaced both the first time i was there the pilot hood was broke. Are there different? lengths of thermopiles? The end of this one is in the main burner flame.

  6. #6
    Join Date
    Apr 2011
    Location
    michigan
    Posts
    172
    Thought I posted the solution to this, but must have forgot, the reason for the failures of the thermopiles was because the wall the heater vented out was to thick for this installation, the installation manual requires the wall to be 6" thick or less if I remember correctly, and the wall in this installation was several inches thicker than what the installation requirements, seems odd that would cause the thermopile to fail that soon, but it is right in the manual, and the manufacturer's tech support said that will cause early thermopile failure. Just glad I was not the installer!

  7. #7
    Join Date
    Dec 2007
    Posts
    4,719
    so the flue gases were backing up into the unit causing the TP to overheat and fail?
    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

  8. #8
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    Sometimes if it has a tstat you have to check wire size and distance, when the thermopile gets weak it will shut the unit down due to small stat wire. I had a fireplace do this. The customer was a dick too, of course the hack who ran door bell wire for the stat made it work and the customer used that as an argument. I said this is not installed right it needs to be fixed to work and sure **** we pulled new wire and it worked fine.

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