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Hello: I'm trying to fix a furnace that is in a home that is not easy to get to (40 miles of dirt road) so I have to do as much research as possible before I make another trip up there. I'm working with a Presidential II electric furnace I don't have the model number at this time but I would guess it is at least 30 years old. I have e-mailed the people living there so hopefully they will be able to send me the model number.

Here is the problem:

Both the furnace and blower do not shut off when the thermostat reaches temp. When you move the thermostat you can here a relay click in the control box but fan and heating elements do not turn off. I did a few checks last time I was up there but did not have good wiring diagram to go off of. The voltage from the 24 volt transformer seemed to off. When I checked the voltage on each of the secondary wires to ground one read 14 volts, the second read 8 volts. When voltage was checked across both wires it was 28 volts. Does this sound correct. I'm sure the problem can not be that complex to fix, I'm just not familiar with the components and there are no diagrams. I would appreciate any help you guys can give me with this problem.

Thanks,
Ethan

Could be a relay or heat sequencer that is defective and not shutting off allowing the furnace to run all the time..

Hi,

Most likely the sequencer or contactor, depending on model.


That is what controls the blower and elements.


The click you hear is probaly one set of contacts shutting down one element, but the set controlling an element and blower is fused shut.

Do you know what brand it is and what KW it is ?


Thanks,
Robert

Thank you for the advice. The model number is 3115-750. Where are the sequencers located are they in the control box? One thing to note is that when you turn the three way fan control switch (heat/cool/off) to off it does not turn the blower off. Does that still sound like a sequencer? There was one blown fuse for the heating elements, I replaced it but there was no change to the condition. What is the correct sequencer part number for that model, I was unable to find it listed in the cross reference cheat sheet? Thanks again for the help and advice.

Ethan

Hi,

Yes, sounds like sequencer problem.


Sequencer # 3115-3571


You can see and order it from our Coleman Electric Furnace parts page.



Thanks,
Robert

Thank you again for your help. I will place an order today for the part. Like I had said the home is out in the middle of no where so there are no easy trips back to town to retrieve forgotten items, are there any special tools I should need to replace the part? Is it located in the control box with the transformer and fan switches?

Thanks,
Ethan

Nut driver (1/4" or 5/16"), screwdrivers, needlenose pliers, wire strippers, wire terminal crimper.

Some wire and terminal ends for high heat.

May not need that, but could go to change the sequencer and find burnt wiring.


Wiring and terminals can be found in our Electrical Parts page.


Let us know if we can help further, we're pleased to assist you.


Sequencer 3115-3571 :

http://www.mobilehomerepair.com/ColemanElec.html


Electrical Parts :

http://www.mobilehomerepair.com/FurnaceElec.html


Thanks,
Robert

I just wanted to thank everybody that helped out and gave advice. I ordered the part, it arrived quickly and corrected the problem.

Thanks again,
Ethan

Hi Ethan,

You're very welcome, thanks for update and ordering with us.

Glad all worked out is good again with the furnace.


Take care and best wishes,
Robert