Coleman 797oc856

[sammysue]

WE have a coleman 7970C856 Presidential Evcon model.. Not sure if it should be a o as in number or O as in letter after the 2nd 7..

But anyways our furnance will run for awhile then shut off then about a minute later it kicks right back on again and runs for awhile again.. then is good for about 15-20 minutes like it should be then it does it again..


Any ideas?? Thermastat?

The repairman was here and fixed a orphis and got the pilot light back like it should be etc etc.. but just made up some bs on the heat exchanger does that sometimes etc etc...

[Robert]

Hi,

All numbers except for the letter C, 7970C856 .


Does the burner go out with the blower motor or just the blower motor ?



Thanks,
Robert

[sammysue]

The blower shuts off then it makes that rumbling noise like it does after it ignites the first time.. does that for awhile and kicks on again and runs for awhile

Blower issue?? Also some times it makes a humming noise you can hear.. Thats not all the time though

[Robert]

Hi,

Could be the blower shutting down, which would cause the limit to shut down burner.

Then starting up again.


May be a fan switch bad for example. Would need to test circuits for voltage to know what is happening for sure.



Take care and best wishes,
Robert

[sammysue]

I see the fan switches are pretty cheap..

Can i replace one?? Seems like it just plugs in

we had a old one laying around.. I think we replaced one years ago..

Are these common to go every 5-7 years??

Do you have one for my model furnance??

I pulled these numbers off the switch

7660-326 it says fan switch below
F110-20F
20050060T82
9225

[Robert]

Hi,

That could be the problem as it is common every 5-10 years to have one act up due to weakened contacts.


Fan Switch # 7975-3281 can be seen and ordered through PayPal from left side of page here :

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



Take care and best wishes,
Robert