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Replacing Coleman Furnace

Posted: Sat Nov 20, 2010 7:39 pm
by tom2001
HI,

I have bought parts from here before, good service! I have a coleman presidential II 85,000 BTU furnace in a 1980 trailer house. I would like to replace the furnace as a whole. I was wondering if a person could replace the furnace with a brand new one that runs on LPG? I do not like that the furnace we have now uses so much LPG and was wondering if the new furnaces are more efficient than the one I have now? Are they a standard fit for a new one? Would they be hard to find, any places online they sell one or like a Menards or somthing?

Thanks for any info!

Re: Replacing Coleman Furnace

Posted: Sat Nov 20, 2010 10:00 pm
by Robert
Hi,

Yes, but may come with gas valve set up for Nat Gas and also the burner orifice.


Would need to be sure BOTH were for LP.

Measure your space and compare to size of new one.


Can buy online or local at any place that carries them and sells to general public.

IF there have been any changes or upgrades to home, go to www.HVAC-TALK.com and look at top tool bar for HVAC-Calc and get it to do a homeowner Manual J Load Calculation to be sure you get correct size btuh needed now.



Thanks,
Robert

Re: Replacing Coleman Furnace

Posted: Sat Nov 20, 2010 10:23 pm
by tom2001
Thanks Robert. I get what you are saying. Do you think the newer ones are more efficient or is it worth keep putting parts in mine? 85,000 Btu's seem like alot for about 1000 sq ft. Sounds like you only need about 65 btu's per sq ft. >>? In MN can get -35 deg F.
Also when the trailer is cold mabey 20 deg or so, should the furnace turn on and off every min or two with the burner running the whole time? After the trailer gets to temp it runs without turning on and off.

Re: Replacing Coleman Furnace

Posted: Sat Nov 20, 2010 10:49 pm
by Robert
Newer ones are more efficient and I would not keep replacing parts in an older gas furnace.


Check your burner tube and burner orifice/spud behind gas valve for blockages(spider-web-bugs).


Thanks,
Robert

Re: Replacing Coleman Furnace

Posted: Sat Nov 20, 2010 11:01 pm
by tom2001
OK, thanks. So it is not normal to turn on and off until up to temp being the trailer is below freezing, works fine after up to 50 or so? Also the flame color is deep orange and good sized, is this color correct? To clean the parts you speak of, do I have to take the burner assembly out?

Re: Replacing Coleman Furnace

Posted: Sun Nov 21, 2010 12:10 am
by Robert
Hi,

No, it should not be turning on and off unless something is wrong.

Flame color should be blue. If it is orange, check the flue pipe and roof jack for separation or damage.

Yes, to check the burner tube and burner orifice, you have to remove the burner and gas valve assembly.

If any of this is not totally comfortable to you, then please get an hvac tech to do it.


Thanks,
Robert

Re: Replacing Coleman Furnace

Posted: Sun Nov 21, 2010 9:40 am
by tom2001
I have replaced all the limit switches through you guys online here. The flame is blue below the plate and all orange above it, is that correct. I have taken out the burner ass. before to put in the thermal couple we received from this online site. Not sure what else would cause the cycling on cold trailer start up, and sometimes it does not work at all, I can turn the (new) thermostate up to 90 and it will click inside the thermostate but the furnace will not kick the burner or fan on, it does nothing. What is a starting point there? Seems like playing with the thermostate it will adventually kick on and work for the rest of the weekend normally.

Thanks for all the replies.

Re: Replacing Coleman Furnace

Posted: Mon Nov 22, 2010 12:12 am
by Robert
Follow white wire from t-stat and where it goes to, see if you have 24vac to ground. IF it goes to the gas valve, see if you have 24vac across GV terminals.

Flame should be solid blue, no orange.

Would be best to call an hvac tech to check that as it is a safety issue.



Thanks,
Robert

Re: Replacing Coleman Furnace

Posted: Mon Nov 22, 2010 9:31 am
by tom2001
Here is what the flame looks like when the burner is running. Also if you could give me a link (if possible) to a transformer for a 1980 Presidential II 85,000 BTU gas furnace. I do not have a model # because it is 4hrs away. I would like to buy it off of your site. I suppose the gas valve is not available? Thanks for your help.

Image

Re: Replacing Coleman Furnace

Posted: Tue Nov 23, 2010 1:17 am
by Robert
Hi,

Transformer # 2940A3541 can be seen and ordered from here by paging down :

http://www.aberdeenhomerepair.com/store ... -120V-40VA


Need furnace model number to know which gas valve is needed.

That burner flame is not good and needs the attention of an hvac tech.


Thanks,
Robert

Re: Replacing Coleman Furnace

Posted: Sun Nov 28, 2010 9:15 pm
by tom2001
Thanks for the link. I went ahead and purchased it from you guys.

Thanks again!

Re: Replacing Coleman Furnace

Posted: Sun Nov 28, 2010 9:17 pm
by tom2001
By the way where is the air inlet for the burner flame on one of these furnaces ? Is it under the furnace and requires removal to get to it ? I went under the trailer last year and did not see an inlet hole or anything through the pan, does it go somewhere else?

Thanks.

Re: Replacing Coleman Furnace

Posted: Mon Nov 29, 2010 4:55 pm
by Robert
If you're talking about the combustion air inlet, it comes through the outer pipe of the flue/roof jack assembly.


What is your furnace model number ?


Thanks,
Robert

Re: Replacing Coleman Furnace

Posted: Mon Nov 29, 2010 5:02 pm
by tom2001
I am not sure on the #'s for the furnace, it is 4hrs away but plan to go there this weekend with the new transformer and check it over better. I better check that roof jack/flue out for any kind of air leak or plugging. Thanks for the help!

Re: Replacing Coleman Furnace

Posted: Mon Nov 29, 2010 5:16 pm
by Robert
You're very welcome, happy to help.


Thanks,
Robert