Coleman electric furnace blower comes on before heat elements

[HayZee518]

ok, now we've established that the control for the whole unit is 24 volt. control transformer has 240 volt single phase between H1 & H2. Therefore the 24 volt control is X1 & X2. Right so far? There may be a circuit breaker or a fuse connected directly to the X1 terminal. How am I doing? X2 is the neutral and you mentioned a white wire. Its good to keep the white wire as a neutral in any circuit. Start changing colors and you open up a can of worms. for the sake of argument, if you had 240 control, keep the wires any other color except white.

[paul52446m]

ok, now we've established that the control for the whole unit is 24 volt. control transformer has 240 volt single phase between H1 & H2. Therefore the 24 volt control is X1 & X2. Right so far? There may be a circuit breaker or a fuse connected directly to the X1 terminal. How am I doing? X2 is the neutral and you mentioned a white wire. Its good to keep the white wire as a neutral in any circuit. Start changing colors and you open up a can of worms. for the sake of argument, if you had 240 control, keep the wires any other color except white.

there is not a neutral wire on his sequencer. the white wire he he talking about
is the low volt white that comes from the stat to energize the sequencer. This unit i do have a wiring diagram to. 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.

Hi John Paul here. HayZee518 found this on a site for your EB10B furnaces.
Sequence of operation-- On call for heat the sequencer is powered from the thermostat and this starts the blower and the first element at the same time.
On the real old units they used a sequencer that started the first element and a heater delay switch started the blower 30 seconds later along with the next element. Later Paul

[JohnO356]

Hi John Paul here. HayZee518 found this on a site for your EB10B furnaces.
Sequence of operation-- On call for heat the sequencer is powered from the thermostat and this starts the blower and the first element at the same time.
On the real old units they used a sequencer that started the first element and a heater delay switch started the blower 30 seconds later along with the next element. Later Paul

That's ridiculous. I wonder why they did away with the delay switch- Save a few dollars?? The old Coleman that I threw away last fall operated like that, and that's why I figured this one was messed up. The cold air coming out of the registers for the first 30 seconds or so sure has increased the power bill

I'm going to hunt around this summer and find a furnace that still brings the heat on first. Which would you say, Miller or Intertherm?

Anyway, thanks a lot to both of you for the help.

[paul52446m]

That's ridiculous. I wonder why they did away with the delay switch- Save a few dollars?? The old Coleman that I threw away last fall operated like that, and that's why I figured this one was messed up. The cold air coming out of the registers for the first 30 seconds or so sure has increased the power bill

I'm going to hunt around this summer and find a furnace that still brings the heat on first. Which would you say, Miller or Intertherm?

Anyway, thanks a lot to both of you for the help.

If you test the two elements with a tester and you find out that one element
comes on 30 or 45 seconds later then the first one , then you can put you blue fan wire on the yellow wire of the second element and you would have your time delay. I can't tell you if thats the way your sequencer, you have to test it or read the specs. later Paul

[JohnO356]

Paul--

I was just thinking (dangerous, I know). but is it possible to wire some type of delay switch into the blue fan wire?

[paul52446m]

Paul--

I was just thinking (dangerous, I know). but is it possible to wire some type of delay switch into the blue fan wire?

Yes John you can do that. Start looking at control co. and look for a time delay
relay. Make sure the switching points is rated for 12 amps. 110 volts and the time delay coil is 24 volts. I don't think that you will want more than 30 seconds timer. If you find what you want we can work on the wiring Later paul

[HayZee518]

go to a site or a local jobber that stocks OMRON relays. Look for a pneumatic relay that has no/nc contacts. NO is normally open, NC is normally closed. Operating coil will be 24 VAC. When the relay is operated the contacts will close after a pneumatic delay which will be adjustable.

[JohnO356]

Hey Paul, as I get older, I've noticed that I often don't see the easy way; seems like I get tunnel vision. I took your advice and moved the fan to the element that starts second. This gives me heat from the lower element and after the delay the upper element and the fan come on.

That's great, just what I wanted, but there's one thing that may be a problem. The lower element gets so hot that the limiter turns it off, it cools, comes back on, and then the upper element and fan come on.

Do you think that could create a problem, or will it be OK. I'm just wondering if the limiter could fail and cause a fire hazard, or would the limiter fail in the "open" position?

[JohnO356]

HayZee-- didn't see your post when I last replied. If you read my last post, that's the easiest way to do it as long as there's no fire danger.

I think that a time delay relay would probably cause the same on-off on the first element as moving the wire did. Am I right?

[HayZee518]

if you wire the pneumatic time delay into the thermostat circuit that goes to the first sequencer, after a time delay the fan will come on and the sequencer will keep on switching on and off the element as heat is needed. if the sequencer goes on to the next element the fan will still be running until the setpoint of the stat is satisfied. then the heater will shut down in the same order as it was started. when it calls for heat again, the pneumatic will actuate, cause a delay and start the fan. if you let the first heat element heat up so hot that the limiter opens, eventually the element might burn out or the limiter may open and NOT reset. The limiter is a safety device. Granted everything in the heater is metal, I would not risk it.

[JohnO356]

Well, if the limiter opened and did not reset, that would be a good thing, right? The element would be off.

[HayZee518]

yes the limiter would open the circuit BUT it will take only so many jolts of high current before it fails open.

[JohnO356]

OK, I've put the blower back on the first element to come on. Not worth the risk, another day or so and I won't need it anyway. I saw a little furnace on the internet last week, either a Miller or a Hamilton, and under it's specs it showed "instant heat", ie: furnace warming before blower starts. I'll find that again and buy it.

I want to thank you both for the help and information, I learned some things. I'm going to keep this forum in my bookmarks..

[paul52446m]

OK, I've put the blower back on the first element to come on. Not worth the risk, another day or so and I won't need it anyway. I saw a little furnace on the internet last week, either a Miller or a Hamilton, and under it's specs it showed "instant heat", ie: furnace warming before blower starts. I'll find that again and buy it.

I want to thank you both for the help and information, I learned some things. I'm going to keep this forum in my bookmarks..

Hi John Paul here. I just read all the messages and that was my concern about
running the element too hot. Thats why i was asking what the timing was between the first and second element coming on. You might be able to handle
30 seconds but not any more then that. and that might still get too hot.
Later Paul