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Thread: Coleman electric furnace blower comes on before heat elements

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    Coleman electric furnace blower comes on before heat elements

    Coleman EB10 furnace. When the thermostat calls for heat, the first thing that comes on is the blower and it's blowing cold air. After ~1 minute the elements turn on and it begins to blow warm air. Both elements are good.

    What I have done:

    Replaced sequencer (twice)

    Replaced both limit switches (even though they both tested OK when I OHM'd them).

    Any one have any ideas? After the furnace blows that minute or so of cold air, it takes a lot longer to warm the place up.

    I did a Google search and found two posts with the same Coleman problem but there were no responses.

    Thanks in advance for any help.

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    Quote Originally Posted by JohnO356 View Post
    Coleman EB10 furnace. When the thermostat calls for heat, the first thing that comes on is the blower and it's blowing cold air. After ~1 minute the elements turn on and it begins to blow warm air. Both elements are good.

    What I have done:

    Replaced sequencer (twice)

    Replaced both limit switches (even though they both tested OK when I OHM'd them).

    Any one have any ideas? After the furnace blows that minute or so of cold air, it takes a lot longer to warm the place up.

    I did a Google search and found two posts with the same Coleman problem but there were no responses.

    Thanks in advance for any help.
    Hi Paul here. There has to be something here that is turning on this fan. I can't believe it comes on with
    just a relay as soon as the stat call for heat. It should not come on until the
    heat coil is coming on. That would mean that it ether has to be wired through the first heat sequencer or the fan has its own switch which would have a heater switch in it. To tell for sure how it is wired up i would have to see your wiring diagram. If you want to take pic. of how it is wired now and pic. of the wiring digram, you can email them to me. Paulm989@hotmail.com
    later Paul

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    Quote Originally Posted by JohnO356 View Post
    Coleman EB10 furnace. When the thermostat calls for heat, the first thing that comes on is the blower and it's blowing cold air. After ~1 minute the elements turn on and it begins to blow warm air. Both elements are good.

    What I have done:

    Replaced sequencer (twice)

    Replaced both limit switches (even though they both tested OK when I OHM'd them).

    Any one have any ideas? After the furnace blows that minute or so of cold air, it takes a lot longer to warm the place up.

    I did a Google search and found two posts with the same Coleman problem but there were no responses.

    Thanks in advance for any help.
    Ok John let start working on this problem. I got your wiring diagram, but it did not come through very good at all. Hard to see the switching.
    The first test i want you to do is, at your furnace wiring panel see if you can find the Blower relay, you can see it on your wiring diagram. On the bottom of the blower relay there is a black wire that goes to the transformer, take that wire off,make sure it is not touching anything and try turning the heat up and see if the blower still comes on right away.
    On your wiring diagram at the bottom of the sequencer you will see a blue wire that goes through a normally closed switch in the blower relay and up to the blower motor. It looks like like on a call for heat the sequencer turns on the lower heating el lament right away and at the same time the heater switch in the sequencer starts heating up. After about 30 seconds or so the
    sequencer switch over to start up the upper heating el lament, and the blue
    fan wire is tied to this second el lament so that is when your blower is suppose to come on. Check out to see if it is wired this way. If you have the fan blue wire tied to the lower el lament, the blower would come on right away. I hope this does not confuse you. get back with me. Later paul

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    Paul, appreciate the help. Just noticed you're from Houghton Lake. I was born and raised further up-- in Houghton. I retired from the army here in North Carolina.

    I put the wiring diagram on Photobucket- but it's no clearer (plus I don't have enough posts here to post the URL. so I'm listing connections/wire colors, and other wire terminal for sequencer below) My furnace is wired exactly as in the diagram.



    When I unplug the black wire on the relay, the fan still comes on first.

    Sequencer terminal connections:

    M1--- Yel from breaker
    M2--- Blue from relay / Yel to upper element
    M3---Yel from breaker
    M4---Yel to lower element

    H1---Blk from transformer
    H2---Wht from thermostat


    Between M1 and M2, and also between M3 and M4 are normally open switches.
    Last edited by JohnO356; 03-25-2010 at 02:05 PM.

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    Whoa-- Don't know how I missed this before, but the upper element is coming on BEFORE the lower element, and the blower runs for about 30-45 seconds before the element comes on.

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    Quote Originally Posted by JohnO356 View Post
    Whoa-- Don't know how I missed this before, but the upper element is coming on BEFORE the lower element, and the blower runs for about 30-45 seconds before the elements comes on.
    That was my next question, do the elements come on at the same time?
    The blue wire on the sequencer that goes to the blower relay has to be wired to the element that comes on last. Later Paul
    Last edited by paul52446m; 03-25-2010 at 03:38 PM.

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    Paul, I've taken the yellow from M4 and moved to M2, and put the yellow from M2 on M4. So the blue wire is still on the top element which now comes on last. It makes more sense to me that the lower element should come on first.

    But-- the fan is still coming on about 30 seconds before the heating element.

    You told me last night to remove the black wire from the blower relay to see if the fan still ran first. Is there any significance to the fact that it still comes on first with the black wire disconnected?

    I OHM'd between the blue and red wire on the blower relay and had continuity so that switch is closed as it should be.

    Is it possible that the blower relay itself could be bad in some way? Do you think I should replace the relay?

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    Quote Originally Posted by JohnO356 View Post
    Paul, I've taken the yellow from M4 and moved to M2, and put the yellow from M2 on M4. So the blue wire is still on the top element which now comes on last. It makes more sense to me that the lower element should come on first.

    But-- the fan is still coming on about 30 seconds before the heating element.

    You told me last night to remove the black wire from the blower relay to see if the fan still ran first. Is there any significance to the fact that it still comes on first with the black wire disconnected?

    I OHM'd between the blue and red wire on the blower relay and had continuity so that switch is closed as it should be.

    Is it possible that the blower relay itself could be bad in some way? Do you think I should replace the relay?
    the only time the blower relay is used is when you turn the continuous fan switch on at the stat, or when you turn the air con. on. When you are heating the power for the blower just goes through a normally closed switch in the fan relay, and we know that is working.
    I need to know if these elements are coming on at the same time or one at a time. if they are one at a time then the blue wire needs to be put on the yellow wire that is going to the element that comes on last. Maybe there is a separate switch in the sequencer for the blower , i can't see that in this diagram.
    When i asked you to take off the black wire from the blower relay. If that fixed your problem that would have meant that there was a short between the white and green wire going to the stat, or you had a problem in the stat, so we have checked that out . paul
    Last edited by paul52446m; 03-25-2010 at 07:05 PM.

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    The elements come on one at a time:

    Lower element first-- connected with yellow wire from M4

    Upper element second-- connected with yellow and blue wires from M2.

    Thanks for sticking with me on this.

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    Quote Originally Posted by JohnO356 View Post
    The elements come on one at a time:

    Lower element first-- connected with yellow wire from M4

    Upper element second-- connected with yellow and blue wires from M2.

    Thanks for sticking with me on this.
    You need to check this with a tester. If only one element is coming on and the blue blower wire is tied to the other yellow wire and that element is not hotted
    up than the blower can not run until the other element is hotted up. Is this the way the blower has alway worked? Ether both elements are coming on together and that would make the fan come on. Or you have the wrong
    sequencer that is making them come on together. You can't tell by just looking at them, you would have to test them. When you check it with a tester check how long it is between the first element to when the second element is hotted up later paul

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