Furnace changes due to recall issues

Questions about repairs and parts for Coleman furnaces, air conditioners and heat pumps for manufactured homes. Click here for Coleman parts.

Moderators: Greg, Mark

Locked
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

I have a evcon dgat070 and last year it was upgraded or downgrade I think because of heat exchanger issue's.

But I am a little ticked that they put a smaller orifice in and cut back my btu's to 64000 now the thing runs more.

When the tech wired in the aux limit switch,why would he wire it into the upper limit for the fan and not the lower for the gas valve??
The schematics on the furnace shows it being in series with the lower limit switch so my last question is
If something goes wrong to open this aux limit switch they way he has it wired won't it just make the fan run all the time.instead of shutting down the gas valve as intended?
In-case anyone else wants to know I live in NW Ohio.

Simidrm
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

The Upper Limit Switch shuts down the Gas Valve in the event of blower motor failure.

Thanks,
Robert
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

The upper limit switch is normally closed switch to I think 180f and when bypassed it just turns the fan on.
when I bypass or unhook the lower limit it shuts down the gas valve,so according to the schmetics it shows wired to the lower limit,which makes sense it would shut down the gv if the temp gets to hot,not just keep the fan running
any way I am replacing both upper,lower limit switches as It's not worth risking a problem later as it is now the lower limit switch went out causing the gv to shutdown at the same temp as the fan comes on and then a get the 4 flash code and I jumped the lower switch and everything has worked correctly,so to be safe I rewired the aux switch from the upper limit to cover the bypassed lower limit as I have ordered both from here a couple days ago.
Normally I wouldn't do this but it was really cold here in the single digits last week so I assume it's safe with aux limit covering for the lower.

simidrm
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

Oh forgot a question,since the upgrade they put in a smaller orifice,would it be any problem to put the origianl size in and go back up to the 70,000 or would you recommend not doing this,my reason for thinking this is since they lowered the btu's to 64,000 it seems to run longer and cycle more then when it was hotter or so it seems to me anyway.

Thanks for the advice and availability of parts.

simidrm
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

I believe the smaller orifice was part of the design upgrade to prevent further problems. i would leave it alone. 6,000 BTU's per hour is not that much of a difference but the heat exchanger will last longer.

hvac1000
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

Leave the orifice as is, it is no longer designed for the larger btu's.

The Upper Limit Switch is as I stated above. It is a safety that in the event of blower failure while furnace is firing, at 180* it will shut the Gas Valve off.

It is NOT to keep fan running.

Thanks,
Robert
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

Ok Thanks for the help and information.

simidrm
archive
Posts: 1054
Joined: Sun Feb 18, 2007 3:24 pm

You're welcome. Just wanted to add that the downsizing of the furnaces during upgrade is a common complaint.

I've yet to hear of anyone who liked it.

Take care and best wishes,
Robert
Locked
  • Similar Topics
    Replies
    Views
    Last post