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Coleman Evcon Digital Thermostat

Posted: Wed Oct 07, 2009 12:34 pm
by jbatt
I have a Coleman Evcon DGAT070BDD furnace with air conditioning and Deluxe Blend Air II. It is vintage 1997 and has the modification kit installed to lower the BTU input to 64,000 but/hr. It currently has a mechanical Evcon thermostat 7670-368/A.
I want to replace the mechanical thermostat with a digital one. I hooked up a Lux DMH110 digital thermostat (4 wire), and it seemed to work OK, but the next morning the furnace's blend air control box started beeping and the red light flashing. The control board in the blend air unit on the roof had to be replaced.
I have gone back to the original mechanical thermostat, but still want a digital replacement.
Did the Lux thermostat damage the control board (the relay contacts may have burned up, but I am not certain). I am afraid to reconnect the Lux thermostat for fear or burning out another expensive control board.
Can I use a digital thermostat with this furnace with blend air and air conditioning? If so, what one(s) are safe to use?
Thank you!

Re: Coleman Evcon Digital Thermostat

Posted: Wed Oct 07, 2009 11:46 pm
by trailrider
I will be interested to see if you get an answer. I am having problems with mine after installing a digital thermostat as well. See my thread "Coleman EB15B Blower Speed".

Re: Coleman Evcon Digital Thermostat

Posted: Mon Oct 12, 2009 12:24 am
by Robert
Hi,

I do not like Lux t-stats and will leave it at that. get a Honeywell t-stat designed for your units that is battery operated. if not battery operated, then run a common wire from transformer low voltage secondary common side to t-stat C.


Thanks,
Robert

Re: Coleman Evcon Digital Thermostat

Posted: Tue Oct 13, 2009 9:34 am
by jbatt
Robert-
Thanks for the reply. Can you give me specific Honeywell thermostats that are compatible with my natural gas Coleman Evcon furnace with deluxe blend air II and A/C?
Thanks!

Re: Coleman Evcon Digital Thermostat

Posted: Tue Oct 13, 2009 2:02 pm
by Robert
Hi,

The deluxe blend air II system is separate and works with any t-stat when wire nutted into circuit.

Any Honeywell t-stat that is listed for gas furnaces and a/c if you have a/c will work. IF you have a/c and it is a heat pump, it will have to be for a heat pump also.

I do not keep a list of all the t-stats would work as there are many, but as long as it states it is for what you have, you will be fine.


You can also take your current one with you to get a matching digital one.


If you get a programmable, get one that is battery operated or you would have to run a common wire from transformer to t-stat for it to work.


For best results, go to an hvac supply store, though better service and t-stats, will also cost more.

You can get good results from Home Depot that will serve you well also. It's just like with anything, you get what you pay for and there are reasons things are cheaper at big box stores.


However, I would not be afraid to buy a Honeywell t-stat at Home Depot and install in my home.



Thanks,
Robert