Coleman electric furnace blower comes on before heat elements

[JohnO356]

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.

[paul52446m]

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

[paul52446m]

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

[JohnO356]

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.

[JohnO356]

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.

[paul52446m]

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

[JohnO356]

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?

[paul52446m]

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

[JohnO356]

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.

[paul52446m]

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

[JohnO356]

Well, Paul, now I'm really lost. I went out this morning and bought a cheap voltmeter so I could check both elements at the same time to see which came on first. Both elements have 240 anytime the breaker is on. I never thought of it before, but if you look at the diagram there are the two orange wires from the breaker going to the elements.

There is also 240 at every terminal on the sequencer, so all I can assume is the white thermostat wire going to H2 on the sequencer acts as a common???? Is that possible?

With everything "hot" all the time but fan not running and elements not heating, is the unit using electricity?

[HayZee518]

one side of the elements are ALL connected to ONE side of the circuit. It may be called L1. The other part of the 240 line, call it L3 or L2 is connected to the common side of each sequencer relay. With the sequencer open or off you'll read 240 from the element common to the sequencer common. with the power off and sequencer open or off you should read NO continuity across the conacts. each sequencer has a coil that operates off a control circuit - maybe 120 volts or 24 volts.

[paul52446m]

Well, Paul, now I'm really lost. I went out this morning and bought a cheap voltmeter so I could check both elements at the same time to see which came on first. Both elements have 240 anytime the breaker is on. I never thought of it before, but if you look at the diagram there are the two orange wires from the breaker going to the elements.

There is also 240 at every terminal on the sequencer, so all I can assume is the white thermostat wire going to H2 on the sequencer acts as a common???? Is that possible?

With everything "hot" all the time but fan not running and elements not heating, is the unit using electricity?

You are testing wrong. One side of the element has a 120 volt line going to it all the time and that power goes through the element all the time but you don't get any heat out of that.
With the unit not calling for heat, put your test leads on both end of the same element and it should no power. test the same way on a call for heat and when the sequencer make you will show 240 volts. later paul

[JohnO356]

"You are testing wrong."

And that shows why I'm at this forum. It will be Sunday before I can mess with this thing again, but I won't quit. Thanks to you both for the responses, I'm learning something every day.

[JohnO356]

one side of the elements are ALL connected to ONE side of the circuit. It may be called L1. The other part of the 240 line, call it L3 or L2 is connected to the common side of each sequencer relay. With the sequencer open or off you'll read 240 from the element common to the sequencer common. with the power off and sequencer open or off you should read NO continuity across the conacts. each sequencer has a coil that operates off a control circuit - maybe 120 volts or 24 volts.

I had noticed that coil between H1 and H2, a 24 volt line at H2. That's why I asked in my earlier post if the white wire from the stat could be a common. I guess I'm misusing the terminology.