coleman furnace short cycles

[korby]

model dgaa090bdta Coleman
serial # 030501334

furnace is coming on just fine, but it is running in short cycles when i call for heat. If my house is 65 and i turn the thermostat to 70 it will run in normal cycles until the house is heated, it seems the problem with short cycles is when the furnace is trying only to maintain the house at the 70 degree temp. I checked the thermostat for loose connections can see any, I am not getting any diagnostic flashes on the furnace, any suggestions?

[Robert]

Did it just start this after running fine for a long time ?


Is this unit new to you(just moved in and first time using it) ?


Has any work been done to it or any parts replaced ?





Thanks,
Robert

[korby]

Robert

The furnace just started to run the short cycles, the furnace is 4 years old and the only trouble i have had to deal with is replace 2 upper control boards and an attic fan on the blend air II syatem. The furnace itself has had no problems. I have lived in the house for four years, I spoke with a friend and he seemed to think it was the thermostat, the furnace shuts off and on with the thermostat, the only differance is the short cycles.

[Robert]

Hi,


T-Stats are the most blamed, but in actuality are the least likely problem often.


However, MH t-stats are also not made that well as some of the other well known ones and do fail.


Usualy when t-stat related, it is the heat anticipator setting being off, but it should be ok since nothing has been changed on it.


You should still check the t-stat for proper voltage readings at all times during cycle, check anticipator (look in homeowners manual or on gas valve for correct setting).


Also, inpect thoroughly the main gas burner orifice for blockage (spides love to nest in there).



Also, check roof-jack for any damage or seperations.



Thanks,
Robert

[Barb P]

Not that anybody asked me, but can I say what happened to me?
When the repair guy replaced my blower assembly recently, the furnace also started having short cycles.
My son had recently put a new t-stat on for me, so I assumed it was that.
He reminded me that I'd been complaining that the new blower blew much harder than the old one.
He said to put a peice of cardboard near the t-stat to block some of the air and see it it made a difference.
I hung a piece of t-paper over the cardboard, that showed the register was blowing the warm air directly on the t-stat.
It satisfied the t-stat before the rooms could warm up.

That's just my story, hope I didn't overstep here.

[Robert]

You're fine Barb, that will cause that. Never have t-stats close to registers, windows, doors or where temp can play havoc on the t-stat.




Thanks,
Robert

[fox]

im a tech. working on coleman dgat070bdd. Board flashed 5- gas valve energized with no call for heat. this was not the case so I replaced the board. New board is doing same thing. the gas valve is not energized. whats wrong

[Robert]

Hi,

Please start a new thread with your question. Under tornadic activity here right now, so may not be able to answer soon.



For now, most likely a short or a bad ground somewhere. Check all wiring.




Thanks,
Robert

[prtrost]

Hi,

In regards to the anticipator settings:

For optimum performance and safety of your furnace, you should never guess at the anticipator settings. Always refer to the manual or contact the manufacturer. You may also be able to get the anticipator settings by looking at the gas valve for the amp setting.

I don't have the manual, (went to Colemans website to see if they had a homeowners manual online, no luck) and I looked at the gas valves and connectors on my furnace. I see some numbers with abbreviations but don't know what I'm looking for. What does the anticipator setting look like? Can you tell me what my anticipator setting should be? Coleman Pres III 7975-856

[Robert]

Hi Paul,

Please post this in with your other thread. We only allow one thread poster so as to not confuse things with multiple problems and inquiries in same thread.



Thanks,
Robert