Hello,

I have a gas heater in my trailer, not quite 20 years old. It heats up very well, but the fan will only stay on for 20 seconds at a time, tops. It seems to be keeping the trailer warm enough, but I suspect it is causing efficiency problems. We have even had someone cone in to look at it, and he had no idea.

Does anybody have any suggestions?

Thanks, Josh

If you are capable, try bypassing the thermostat heating circuit to see if the unit will sustain a longer cycle. If it does, start looking closer at the thermostat as the culprit.

Is the burner cutting out also in 20 seconds?, I guess you know someone is going to ask you the brand name anf the model number,, so be ready,, :)

I'll do it! I'll do it! What is the brand and model # ?

If the fan is only staying on for 20 seconds or so and the burner keeps burning during that time then usually one of two items comes to mind.

The burner is not operating at the proper BTU output. This will cause the fan to short cycle since the burner cannot keep the furnace hot enough to keep the fan activated.

OR

The fan motor control sometimes called the fan and limit control could be out of calibration or defective allowing the fan to short cycle or the blower motor itself could be defective.

Furnace filter clean?
Are all the registers open?

This could also cause a problem.

:D
I'll do it! I'll do it! What is the brand and model # ?


:D:D you did good;):rolleyes:

I just love a dare!:p

Thanks for jumping on this, guys! I forgot to check the make and model before I left this morning, but I can tell you that I change the filters at the beginning of every cold season, and until recently, some vents were blocked off in a room we weren't using, but they are now all open. I will report back later with more info.

Thanks,
Josh

but I can tell you that I change the filters at the beginning of every cold season

BUT you do change them at least every two months?

I don't, but I usually will vaccuum them out. Do you think leaving them in could've caused damage?

No as long as they were clean and in most cases you can see light through them

Thanks for the responses, everyone. I wanted to update this because the problem has gotten worse. It will now only stay on for about 15 seconds at a time.

The make and model:
Miller MGHA-075ABFC-01
Natural Gas Burning
Blower model: 461350

The burner is still getting good and hot, so is it possible I might just need a new blower?

That is possible but it could also be the blower control. If you have a thermostat that has a blower on switch turn it on then the blower should run all the time. If not jump the blower control disc to see if the blower will run for a longer time. If not or the motor is getting hot then it is probably the motor going bad.

Go to furnaceparts.com,they should have a motor.

Mower_Man
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Good Luck,you will need it.