heil propane unit

Discussion in 'HVAC' started by tndave, Mar 7, 2011.

  1. Mar 7, 2011 #1

    tndave

    tndave

    tndave

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    MOdel NULK100DH03 867.779432

    It had been clicking a lot while it was running so I watched it and the flame would go out but the main blower would stay on and then in a couple minutes the flame would re-light. It did that for about a month now it's not heating at all. When you turn it on and it gets heat signal (checking board at C & W terminals I get 24 volts) Nothing happens for a while and then the main blower comes on, but no flame, inducer fan never comes on, no clicking sounds & ignighter never glows. There is no voltage going to inducer motor. There is gas in the tank. Picture included.

    Thanks!!

    HVAC2.jpg
     
    Last edited: Mar 7, 2011
  2. Mar 7, 2011 #2

    tndave

    tndave

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    18 views and no ideas? It's getting cold in here :help:
     
  3. Mar 7, 2011 #3

    paul52446m

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    If you are getting 24 volts from c to w then the board should be turning on the inducer, If not change the board because the relay in the board is not powering the inducer. Paul
     
  4. Mar 8, 2011 #4

    tndave

    tndave

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    Thanks...I don't see a open circuit board, so I assume that this is it in the picture below. I have another one & that's the first thing I did was try the other one & it didn't help...of course I don't know if it's any good either, it was just sitting on top of the one in use. I guess there's not a way to test it...I'll just have to buy one & try it..?

    Hopefully I can find one locally cheaper than this... Hot Surface Ignition Control Module.(Amana, Goodman, Trane, White Rodgers, York): American HVAC Parts

    AC01.jpg
     
  5. Mar 8, 2011 #5

    paul52446m

    paul52446m

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    That control is for the ignition. You do not have a board like i thought you had. Follow the 120 volt wires from the inducer back down to see where they go. One wire should go to a relay. That relay should have a 24volt coil to make it . See if you can check that relay for 24 volts. If you have 24 volts and its not making the 120 to go to inducer, then that relay is whats bad. paul
     
  6. Mar 8, 2011 #6

    tndave

    tndave

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    Ok, the relay has 6 wires & it is getting about 95 volts on one post (the black wire coming from the transformer) & 29 on another (red wire coming from low voltage board) and it is not putting out anything on the heavy black wire which goes to the inducer. None of the other posts had voltage...it is labeled "System Relay in the diagram.

    Thanks!!

    ACDIAG.jpg

    ACR1.jpg

    ACR2.jpg
     
    Last edited: Mar 8, 2011
  7. Mar 8, 2011 #7

    paul52446m

    paul52446m

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    On your system relay post 7 and 8 is your 24volt power so check these two post on a call for heat to see if you have at least 24 volts, if you do then the relay should snap close and start the inducer.
    I can't see the top side of you wiring. Have you checked the roll out switch's
    to make sure you are getting power through them to go to the relay. Paul
     
  8. Mar 8, 2011 #8

    paul52446m

    paul52446m

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  9. Mar 8, 2011 #9

    tndave

    tndave

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    When I was origionally testing voltage I slipped the terminals up each post far evough to get a probe on the post & 8 showed 0 voltage. But now more testing reveals that if I disconnect it and just test the wire it has 25 volts. Once when I had the tester probes on 7 & 8 & squeezed toward each other in an effort to make sure I was getting good contact the inducer came on for about 3 seconds. But I have cleaned the post & squeezed the terminal & wiggled & it won't come back on. I don't see any corrosion or anything like that. I guess that little relay is just sucking all of the ampage so the meter shows 0 volts. I even tested the other end of the wire and it shows the same thing.

    Thanks!!
     
  10. Mar 8, 2011 #10

    paul52446m

    paul52446m

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    sounds like you better put a new relay on . Relays like that will do that clicking
    if they have low 24 volts or just getting bad coil or contacts points.
    Later Paul
     
  11. Mar 10, 2011 #11

    tndave

    tndave

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    Got a relay & it didn't help. Still 25 volts (big red wire) coming from "Fan & Limit Control" (pictured below & I replaced it last year, best I remember) until I plug it into relay & then it goes to 0 Volts or very close to it.

    SCH01.jpg

    LIMIT.jpg
     
  12. Mar 11, 2011 #12

    tndave

    tndave

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    To clarify post 5 has 98 volts, post 6 has 28, post 8 has 0, but if I unplug the wire and test the wire it has like 28 & post 3 has 0 volts. I tried post 3 with the wire that goes to the inducer off & it was not getting any current. Any help would be greatly appreciated.

    Thanks!!
     
    Last edited: Mar 11, 2011
  13. Mar 11, 2011 #13

    paul52446m

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    Ok you say that post 5 has 98 volts, If you follow the main 115 volts Hot power through the wiring diagram, it goes through door switch or interlock switch, down to 6 on fan relay, bK over to transformer and then over to your 5 post on system relay This should be 115 to 120 volts all the way. so check and see where you are losing voltage, should not be down to 98 volts.
    After you get this right then on a call for heat you should get 24 to 27 volts when testing across from 7 to 8 on system relay. Check all this out first.
    Paul
     
  14. Mar 11, 2011 #14

    tndave

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    It's 98.3 coming out of transformer (black wire). 28 going into transformer (blue wire)
     
  15. Mar 11, 2011 #15

    paul52446m

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    Ok you say that post 5 has 98 volts, If you follow the main 115 volts Hot power through the wiring diagram, it goes through door switch or interlock switch, down to 6 on fan relay, bK over to transformer and then over to your 5 post on system relay This should be 115 to 120 volts all the way. so check and see where you are losing voltage, should not be down to 98 volts.
    After you get this right then on a call for heat you should get 24 to 27 volts when testing across from 7 to 8 on system relay. Check all this out first.
    This is the same message that i gave you in message 13. You have to check step by step the way a tell you or we are not going to find the problem. I said start with the incoming power Hot line and then follow in through the system like i said. I can't tell you where you are losing power, so read post 13 and go step by step. Paul
     
  16. Mar 12, 2011 #16

    tndave

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    The voltage drop is due to the ground. If you use the ground that comes out of the fan relay you get 98-99 Volts at post 5. If you use the main common you get 125. I connected a ground straight from main common to common on low volt board & that gave me 125 between post 5 & 7, but that didn’t help. I later took the jumper wire that I added off...

    I found if I wiggled the wire from the limit to the relay (the one that was going down to 0 volts under load) that the inducer came on. So I got that connection (at the limit) cleaned and snugged up & the inducer works. Now the inducer comes on, the igniter glows and it flames up…for about 3 or 4 seconds & turns the gas off. It does the same again & shuts down. Cleaned up the flame sensor & now it works fine. I guess the connection at the limit was the original problem & the flame sensor was just an added bonus…

    Thanks for your help!!!
     

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