HELP PLEASE LP HEATER

Discussion in 'General RVing' started by -TOM-, Oct 9, 2004.

  1. -TOM-

    -TOM- New Member

    hi all. my 2 yr old heater {atwood lp} will light and then go out in 5 seconds OVER AND OVER. is there a way to check the igniter sensor to see if it is the problem? does it put out a voltage when it is lit?
     
  2. Gary B

    Gary B Senior Member

    HELP PLEASE LP HEATER

    Hi Tom, what kind of a heater are you asking about, a water heater or a furnace? If its DSI (direct spark ignition) it sounds like the circuit board is not getting a flame sense signal, it could be alittle corrsion on the electrical connections, if after cleaning them and you have the same results then the circuit board flame sense circuit has failed and you'll need to replace the board. Check here for some good trouble shooting imformation www.dinosaurelectronics.com
    Dinosaur Electronics build the best circuit board there is bar none. Good luck :) :laugh: :cool: :bleh: ;) :approve:
    PS the flame is sensed thur the ignition electrode it must be in the flame and be red hot, if no flame is sensed the circuit board shuts off the LP gas valve in approx. 6 seconds.
     
  3. -TOM-

    -TOM- New Member

    HELP PLEASE LP HEATER

    TY IT IS A FURNACE. DO YOU KNOW WHAT THE THERMAL PILE VOLTAGE MIGHT BE?
     
  4. Kirk

    Kirk Senior Member

    HELP PLEASE LP HEATER

    Tom,

    Your Atwood furnace uses an ignitor that is also the flame sensor and it sounds as though yours is not sensing the flame. The output of the sensor is in the miliamp range and is very difficult to measure. If the probe is located directly in the flame and it is still not sensing, it is probably bad. But it could also be a failed control board. I would try the ignitor first, since it is only about $35 - $40. And with a 2 year old furnace it isn't likely that to be the circuit board, which will cost more than $100.
     
  5. Gary B

    Gary B Senior Member

    HELP PLEASE LP HEATER

    Hi Tom, rv furnaces haven't used thermal Plyes since the late 60's early 70's. What is the model of the furnace and how old is it? If its only 2 years old then as I & Kirk have posted its one of the two things posted either the flame sense or the circuit board. The circuit can be tested at a rv service center. :) :laugh: :cool: :bleh: ;) :approve:
     
  6. -TOM-

    -TOM- New Member

    HELP PLEASE LP HEATER

    if it dosent use a thermal pile then how does it sence the flame?
     
  7. Gary B

    Gary B Senior Member

    HELP PLEASE LP HEATER

    Tom, the circuit board is like a small computer, with many circuits in it, there is a delay timer circuit, a gas valve circuit, an ignition circuit & a lock out circuit and more. In the ignition circuit the last part of it is the hi-tension (spark) coil/transformer it sends the spark to the electrodes which ignites the gas, as the electrode get hotter and eventually turning red hot the electrical resitance increases making it harder & harder for the transfer to cause a spark, and the hot electrode generates mili/milivolts the circuit board notices this and says hey we have flame and turns off the ignition phase and locks on the gas valve. Now if the ignition electrodes have a craked insulator or is shorted some how then the circuit board doesn't sense a flame and goes to lockout shutting off the gas valve circuit, if the circuit board has failed it can be any number of things , one of the things is that the secondary winding in the coil has an open, the hi-tension electrical can jump the open, but the low voltage sense voltage can not jump the open, thus no flame sense. :) :laugh: :cool: :bleh: ;) :approve:
     
  8. bgalbraith

    bgalbraith New Member

    HELP PLEASE LP HEATER

    I just went through the same problem with the DSI furnace in my fifth wheel. It would ignite three times and the flame would go out 5 seconds after each ignition. Then it would lockout for an hour and try again. I pulled it apart and bent the ignitor/sensor so it was more in the flame and it has worked fine ever since. :laugh:
     

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