[OrionAncient]

I have a mobile home coleman gas furnace. when we moved in 6 months it worked fine. within 5 10 minutes of turning it on, the house was whatever temperature we wanted it at.

now though, out of the blue, it wont heat.

me and my father have both looked at it. weve reset the system twice.
the air filter is dirty, but only a little bit. you can see your hands through it just fine for the most part.

so heres what it does.

the house is 60 degrees F. so we set the thermostat to 74. it takes a good 5 to 10 minutes to turn on. it used to only take maybe 2 minutes. then we look in the gas compartment, and just like always you can see a nice big blue flame burning, just burning superbly. the air from all the vents throughout the house have a great forced air coming out. but its cold, or lukewarm. its definitely not the same HOT air we used to feel. and then after 8 hours of leaving the heater on, the temperate is either still at 60, or its gone up to maybe 62.

also when we turn the heater off, it seems like it takes a good 5 10 minutes to shut off.

everything seems to be in working order. weve checked all the valves, burners, everything that the common man knows to check.

but still no heat?

please any advice or suggestions are needed. im on a budget and my house is on average 40-50 degrees now. and my wife is starting to get real tired of it......

 

[Yodaman]

You may have a 2 stage heater that is not kicking into high heat. Post your furnace model # and fuel type. It will the help the HVAC pros to better help you

 

[supers05]

Along with the m/n, post a picture of the flame

Cheers!

 

[user_12345a]

A real two-stage furnace would have the blower at a lower speed on low fire.

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Watch the furnace run for a good 15 minutes and see if the burner cuts out. It shouldn't.

Clock the gas meter, as having it under-fired will cause low heat output. google gas meter clocking.

Measure the temperature rise, google how to do it.

 

[OrionAncient]

the burner stays lit for the whole time i leave the furnace on.

the flame box area, the flame is a good 5 or 6 inches tall. im not sure if that normal or not for the flame to be that tall, but i mean theres no doubt it burning the fuel,

as far as fuel type, all i know is its natural gas.

 

[OrionAncient]

and i read up on 2 stage heaters. this sounds nothing like what i have. my heater has always kicked high warmth/hot air, regardless of what the thermostat is set to, or what the outside weather is like. i mean this thing doesnt even kick out lukewarm air anymore. last time i ran it it felt like the ac was running.

 

[user_12345a]

Do a temperature rise test (supply - return temp in the ducts) and clock the meter. Post the results.

Where are your ducts located? I'm thinking you may have a disconnected return or something pulling in 100% unconditioned air.



http://www.structuretech1.com/2013/11/diy-furnace-test/

Switch the furnace on a monitor closely - post sequence of operation. What did you mean by takes 10 minutes to come on?

 

[beenthere]

You said the flame is several inches high. Is it a good wide flame also?

Does the flame move around a lot when the blower comes on?

Post full model number and serial number. The DGAT line of Colemans had a recall on them several years ago. And your may be one that slipped through the crack and not fixed(burned through heat exchanger).