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O/T: Any HEATING and COOLING guys out there?

Discussion in 'Uncategorized Threads' started by Tron, Oct 20, 2008.

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  1. Tron

    Tron Supporting Vendor Supporting Vendor

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    OK, here's the problem- I have a "Hot Dawg" hanging heater in my garage that I bought new 7 years ago. I went to fire it up for the 1st time this year and the coils heat up (gas is on and it ignites), but the fan is not kicking on. What should I look for first?

    Thanks much!
     
  2. kutzygunner

    kutzygunner TS Member

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    sounds like your thermocoupler is bad . another possibility is the vacum switch needs to be reset . try one or both . good luck . p.s. make sure your exhaust vent is clear .
     
  3. Laudygirl

    Laudygirl TS Member

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    Could be a furball wrapped up in the blades?
     
  4. Tracer

    Tracer Member

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    Check the thermoswitch. Should be a small disc about 1 inch in dia. with 2 wires plugged on it. It senses the heat from the heatexchanger and a bi-metal switch turns on the fan on a temp. rise. This switch also allows the fan to run after the fire is out to extract all the heat in the heat exchanger. Check also for a resetable saftey switch at the top of the furnace. If you have achieved a fire then your thermocouple is ok as its job is to allow the gas valve to come on if a standing pilot is heating it. Hope this helps. Del Miesner, Northwest Heating and A/C Service
     
  5. Ljutic111

    Ljutic111 TS Member

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    If there is a fan/limit switch , that may be bad or has to be lowered for the fan to come on ?? Looks too new for something to be faulty .
     
  6. Hauxfan

    Hauxfan Well-Known Member

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    I'd check to see where your cat is first. It may be caught up in the fan and is stopping the fan from running. lol

    Hauxfan!
     
  7. Tracer

    Tracer Member

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    Just another thought. If your furnace is only 7 years old you may have a system with a hot surface igniter. If you do, you should see a "glow" from the igniter, when you try to fire up the system. If you do have that type of igniter, you will find that you have a "PC" board that controls it. Looks like a board out of a computer about 3 or 4 inches square. On that board you will find an intrigated relay which looks like a small black or blue box about 3/4 inch square that starts the fan. That relay could have burned points in it which won't allow the circuit to be made to the fan. If you pull that board off, look on the back side of it and see if there are any burned spots. Either way you will need to replace the board since it is not repairable. Del Miesner, Northwest Heating and A/C service.
     
  8. cubancigar2000

    cubancigar2000 Well-Known Member

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    I had same prob, it was the thermo coupler, simple repair
     
  9. Tron

    Tron Supporting Vendor Supporting Vendor

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    You should be able to test the thermo coupler (aka Limit switch) by bypassing (jumper wire), correct? If so, I did that and still nothing.
     
  10. Tron

    Tron Supporting Vendor Supporting Vendor

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    Mr. Charles and I seem to think it's gotta be the circuit board. This unit does have a LED diagnostic system and it flashes out a code 4, which is "Limit Control or Flame Rollout switch". The fan motor seems to be OK because I checked power out of the relay and there isn't any. The relay is remote from the circuit board and it never gets voltage to actuate it....but, I only have 2.3 Ohms of resistance accross the relay coils.
     
  11. Catpower

    Catpower Molon Labe TS Supporters

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    If the led for the roll out or limit switch is flashing, you need to find the switch, as it is propably a manual reset, it will have a little button you need to push on it to reset it. Then you need to find out what turns the fan on, it could be the board or it could be a bi-metal switch.

    When you tried to start the heater, the gas came on, warmed the heat exchanger like it's supposed to, but the fan didn't come on so it tripped on high limit, like it was supposed to, you just need to find out what is controlling the fan, and not working the way it's supposed to.

    Wish I could give you more info, I'm not used to working on stuff that new!!!!!
     
  12. gamehog2

    gamehog2 TS Member

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    Tron,

    Your heater is made by Modine. If you have the model number I can look at the specific wiring diagram for your unit; however the diagrams I did look at had a time delay relay for the fan. Do not know if they are on the board or not??? The limit code is as Catpower said, due to the unit coming on but the fan not starting. On some units they are manual reset (you have to push a button to reset)on others they are auto reset. Follow the fan wiring back and find out what that is connected to and then you can give us further information that we can use to help.

    Darrel
    Powell Heating & A/C
     
  13. Tron

    Tron Supporting Vendor Supporting Vendor

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    Model #HD 6AH0134 Serial # 30011025001-9987

    Thanks
     
  14. Steve NJ

    Steve NJ Member

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    Joe, My home heating system has that problem occasionally. It has a flame sensor to verify it’s lit. If it has no flame it shuts down. It has a thermocouple (sensor) in the flame area and it gets dirty. I have to take it off about once every winter or two and clean it with fine Scotch Brite. End of problem. Hope this helps.
     
  15. twopipe

    twopipe Member

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    that wiring job you have there is looking to start a fire. Do it properly !
     
  16. Tron

    Tron Supporting Vendor Supporting Vendor

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    Two pipe, that extension cord DOES NOT go to the heater. The heater is hard wired with it's own breaker. It is proper.
     
  17. gamehog2

    gamehog2 TS Member

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    Tron,

    I pulled up and looked at the actual wiring diagram for the unit you gave me the model number for. By looking at the diagram, the relay that controls the motor is built into the board. If you are sure that the motor is good, you will need to replace the board. If you have a meter, make sure you do not have 115 volts to the motor. If not it has to be the board.

    This unit according to what I am reading uses a hot surface ignitor as an ignition source so it does not have a thermocouple, only a flame sensor. (No they are not the same thing) If the unit is lighting and running for a period of time (45 sec to 120 sec) and then shutting off, it is not a problem with the sensor and the unit is going of on the high temperature limit. According to the drawing it is manual reset (you will have to find and reset it).

    Hope this helps
     
  18. Tron

    Tron Supporting Vendor Supporting Vendor

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    OK, circuit board ordered. The new style circuit board (according to the guy at the H&C place) comes with an integrated relay. The original set up has the relay remote from the board.

    Thanks everyone!
     
  19. Tron

    Tron Supporting Vendor Supporting Vendor

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    <a href="http://smg.photobucket.com/albums/v712/Tronspace/?action=view&current=100_0569.jpg" target="_blank">[​IMG]</a>


    Jeeze. If you guys MUST know, then OK. The extension cord powers up a traffic light that I've has since my days as a men's clothing salesman. After I worked at the gun club, I landed a job selling men's clothing at the local department store. The traffic signal was where the children's department started and was one of the displays. When they remodeled the store, I got the stop light.

    Some of the locals may remember "R&M Department Store"

    Tron
     
  20. Tron

    Tron Supporting Vendor Supporting Vendor

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    Well, thanks to Mr. Charles who sent me a new relay, I didn't have to spend an outragous sum for a new circuit board after all. I wired up the new relay and I'm good to go.

    You ROCK Mr. Charles!
     
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