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Limit switch for Coleman Direct Vent Forces Air Furnace 7956

Posted: Mon Oct 29, 2007 9:31 pm
by foolios
I was reading the directions about the limit switch needing to be inspected in case there was a need for resetting the furnace blower motor.
I don't believe I am having a problem with the motor, but I was curious about this switch. Currently it appears to be in the down position. I am assuming that this particular switch must raise when it needs resetting?
I don't remember whether I've ever had to use it and I was wondering/hoping that this was the case. It doesn't go down any further and as far as I know I've never had to push it.

Thanks in advance.

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Mon Oct 29, 2007 10:24 pm
by Robert
It cuts off the gas if the blower doesn't come on and you then reset it.


To test, remove wires and ohm the terminals to see if it has continuity meaning it is closed.



Thanks,
Robert

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Mon Oct 29, 2007 11:00 pm
by foolios
"To test, remove wires and ohm the terminals to see if it has continuity meaning it is closed. "

I do not know what you mean by ohm the terminals. And I'm not sure which wires you speak of so I guess I'll just leave that be.
But I am still wondering why that little red button is in the down position....

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Mon Oct 29, 2007 11:39 pm
by Robert
Turn power to furnace OFF. Remove the wires from the limit switch terminals. Mark where they go beforehand though.


Set multi-meter to test for ohms/resistance.


Place one lead on each terminal of switch.


It should be closed and show continuity by giving a reading or needle movement, depending on type meter used.



The button could be stuck, but if the switch is closed all is ok.


The thermocouple cannot be sanded. It is either good or bad and if bad, must be replaced.


Ours are $24 + $6.75 shipping.



Thanks,
Robert

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Mon Oct 29, 2007 11:45 pm
by foolios
THank you for the information. I will give it a try and see what results tomorrow evening.

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Mon Oct 29, 2007 11:48 pm
by Robert
You're very welcome.



Take care and best wishes,
Robert

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Tue Oct 30, 2007 12:06 am
by foolios
I am considering your offer on the part.
It's like this one right? For my furnace listed in this thread.
Coleman Direct Vent Forces Air Furnace 7956A856

Here's one I had found before I found your site:
http://bestbuyheatingandairconditioning ... _Code=rs-t

You may have the better deal.

If you could give me the link to yours, I will consider buying it from your site.

Thank you in advance.

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Tue Oct 30, 2007 12:12 am
by foolios
2631-3481 Thermocouple 24"

Thermocouple senses pilot light and closes gas valve if none sensed. Used in most all furnaces with a pilot light except those with a sparker. Replaces 2631-347, 2631-3471, 2631-348 & 026-34038-000. Your price $14.74.

is the only one I can find on the site.
I'll have to measure mine and post a picture of it.
Or do you just need my gas valve model number or something?
I will check the length because it may be the 30" one from the other link I posted in the previous post.

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Tue Oct 30, 2007 12:29 am
by Robert
http://www.mobilehomerepair.com/ColemanGas.html



Thermocouple/24" # 2631-3481 @ $14.74 + $6.75 shipping .


Right side at above link, click pic for enlarged view.


It is the Thermocouple listed for your furnace. They come in all sizes, you won't need any longer than 24".


If interested, please add to cart and order through PayPal or call

toll free tomorrow after 9AM CST to 1-877-263-7860 and charge to

Visa or Mastercard.


If outside the U.S., let me know for added info.



Thanks,
Robert

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Tue Oct 30, 2007 9:26 am
by foolios
Thank you so much. I ordered and paid for it this morning.

About how long does priority mail take?

Thanks again for all the help. I will appreciate being warm again. And so will the girls.

=)

Re: RE: Limit switch for Coleman Direct Vent Forces Air Furn

Posted: Tue Oct 30, 2007 9:58 pm
by foolios
Robert wrote:Turn power to furnace OFF. Remove the wires from the limit switch terminals. Mark where they go beforehand though.
Set multi-meter to test for ohms/resistance.
Place one lead on each terminal of switch.
It should be closed and show continuity by giving a reading or needle movement, depending on type meter used.
The button could be stuck, but if the switch is closed all is ok.
With your help I was able to figure out how to test the limit switch. On my multimeter there is a symbol for current passthrough.
WIth the power off to the furnace and the wires removed as you instructed.
With that particular setting on the multimeter I was able to see that a tiny current passes through the multimeters leads.

Thank you very much for your assistance.

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Wed Oct 31, 2007 2:36 am
by Robert
Hi,

You're very welcome and thank you. Be sure to mount t-couple so that the pilot flame crosses the top 1/2" to 3/4" ONLY.

At gas valve, be sure it is straight going in and tighten maybe small amount past finger tight.

VERY easy to ruin here, so don't overtighten, just good and snug.




Take care and best wishes,
Robert

RE: Limit switch for Coleman Direct Vent Forces Air Furnace

Posted: Wed Oct 31, 2007 7:59 am
by foolios
Awesome, thanks for the tips.
I'll let ya know how it turns out. =)