Coleman Presidential II model # 7680B

[tigermom4]

Our furnace had worked fine on Sunday Oct.14 and then Monday night the thermostat wouldn't click on at all. The pilot light is lit and everything seems to look like it did when I lit the pilot light.
Our thermostat looks really old so we are getting a new one today. I was wondering if it is not the thermostat what else could be wrong.
Thank you

[Robert]

Hi,

Give me the three series numbers to complete the model number please.


7680B??? . Then I can see what your unit has.



How many wires connect to t-stat ?


If only two, turn power to furnace OFF, tie the two wires (usually red and white) together, set t-stat temp where you want it and turn power back ON.


IF it works fine (you'll have to turn off at breaker), then the t-stat is bad.


If more than two, do same with just red and white.


If other colors, wait for t-stat replacement.


Be sure t-stat is for your type unit and number wires.


If programmable, get a battery operated one.



Thanks,
Robert

[tigermom4]

Thank you for your help.

The number of our furnace is 7680B Series 856 Presidential II

I replaced the thermostat and still nothing. There are two wires at the thermostat Red and White. I hooked it up per instructions on the package. I did get a battery operated one as you suggested.

I checked all the wires that I could see at the furnace and everything there looks connected.

The pilot light is still going. I turned it off and relit the pilot and it stayed lit.

My son said to look for a reset botton but I didn't know where to look. Does this furnace have one or maybe a fuse that could have burned out?

I would really appreciate any suggestions you have.

Thank you

[Robert]

Hi,

You should have a limit switch mounted to the side of the blower housing and it possibly will be a manual reset with a red button.


At t-stat, red to RH and white to W.


The t-stat could still be one that is not compatible with 2 wire systems.


Did you try tieing the red and white together to see if furnace worked, that bypasses the t-stat ?



If you have a multi meter, place one lead on red and one on white at t-stat and test for 24-28vac.


You should read 24-28vac and when t-stat closes on call for heat, you should read 0vac.


IF you get those readings ok, test across the gas valve for same 24-28vac.


Also, check the gas valve to burner orifice for blockage from spider/web.




Thanks,
Robert

[tigermom4]

Hello again, sorry I'm not getting anything to work.

I checked on the T-stat and it said it was compatible with 2 wires I just had to remove the jumper they had in the spot for the Rh wire and I put the white wire in the W spot.

When I put the new T-stat in I did put the wires together and nothing happened. It didn't come on or anything.

This morning I vacuumed it all out and double checked by the Pilot light everything I cleaned.
I don't have a meter or tester.

I did find a small black circle connector, probably the limit switch you mentioned, with two wires attached to it on the side of the blower on the back left side, but there was no red button just a small hole.

It's really weird because it was working fine and then just nothing.

Thank you for taking the time to answer my questions.
Dee

[tigermom4]

I have a new development.
I turned off the power to the furnace and pulled both wires off of the switch attached to the side of the blower, and put them back on. I then turned the power back on and the furnace worked. But the only way it will work is if you keep doing that. It won't come on by itself.
Do we need a new limit switch or could something else make it kick off like that?
Thanks Dee

[Robert]

Hi Dee,

Tie those two wires together tightly or jumper that switch with wires attached.



Then set t-stat for normal operation, if it works fine through a few cycles, probably an intermittant fault with the switch.


DO NOT leave jumpered or tied together when not home or asleep.



Let me know how it does.



Thanks,
Robert

[tigermom4]

Hi Robert,

The wires on the switch have clips on them so that made it easy. I took them off the switch and taped them together with electrical tape. I turned the power back on and set the T-stat and it worked several times as long as the wires were together.

I turned off the power and put the clips back where they went. It worked only one time like before when I turned the power back on.

It looks like there are two small screws that hold that switch on. I didn't do anything else with it. I was going to wait and hear back from you.

Thanks so much,
Dee





































































Thanks for all your help.

[tigermom4]

Hi Robert,
I wanted to let you know that I went ahead and took the switch off today and got a new one. I found a place this afternoon that had the part. On the news they said it was going to get pretty cold Sunday and Monday so I thought I should try and it works fine now.

I'm thankful for your help and God bless you for helping people the way you do.
Have a good weekend and take care,
Dee

[Robert]

Hi Dee,

You're very welcome, happy to help.

That's great news, glad it took care of it for you. Thanks for the

kind words, I appreciate it.


You have a great weekend as well.



Take care and God Bless,
Robert