Furnace wouldnt turn on...then did.?

[Jason D]

I have a 2011 MPG183 that i recently purchased. I verified the furnace turned on and heated before purchasing. After purchasing I replaced both LP tanks, verified furnace worked as it should. Today I went to start it to see how long it would take to heat the camper since it finally got cold. Nothing....stove works so I know the gas wos flowing. I turned the furnace switch off to check the fuse. Pulled the fuse, it was good, put it back in and the blower fan turned on immediately, with the furnace in the off position. From there it worked as expected, blowing heat. Any idea why it turned on immediately after the fuse was replaced? Why didnt it turn on prior to the fuse being pulled? Thanks in advance.

Jason

 

[cookie]

I can think of two scenarios, the fuse was not correctly installed and a bit loose causing intermittent contact and possibly a loose wire connection on the back of the fuse panel.
Just a couple thoughts.

Peace
Dave

 

[Jason D]

This morning i tried again, turned on the LP slowly, turned the furance switch on, turned up the thermostat. It would not turn on. Pulled the fuse, as soon as it was replaced, the furnace turned on.

 

[jerryjay11]

If you haven't done so yet, next time try turning the furnace switch on then move t-stat up, then turn furnace switch off, then on again without touching the fuse. if it doesn't come on try pulling the T-stat off the wall and place it back on again. If it comes on, I'm guessing the furnace control is tripping off on safety. Possibly a missed wired T-stat where the red wire is maintaing power to the control so when you shut off the LP for the night and the temps drop the furnace is attempting to start without LP, thus going off on safety. Pulling the fuse is taking power off the control, allowing it to reset. The T-stat wires are color coded to match the color code letters on the base of the T-stat.

 

[wdk450]

I'm wondering if this is an intermittent bad circuit board that is somehow reset by a long interval between tries, or by completely removing power (removing the fuse).

 

[jerryjay11]

I'm wondering if this is an intermittent bad circuit board that is somehow reset by a long interval between tries, or by completely removing power (removing the fuse).

That certainly could be the issue since it is a 14 year old camper. I would still do the T-stat test as the furnace control should have no power on it with the T-stat switch in the off position. If the control doesn't have power, then it can't attempt to start to eventually trip with LP shut off. Keeping in mind the T-stat doesn't send power to the control until the temps drops below the temp setting of the T-stat. Also, the furnace may trip on safety a couple times waiting for the LP to get to the it. But it sounds like it is tripped before his attempts during the day.

 

[Jason D]

If I turn the thermostat on first, the blower does turn on, then the furnace switch anf all is well. I am assuming those the steps. I appreciate the help.

 

[jerryjay11]

To reset the furnace after a safety shutdown you turn the T-stat on-off switch to off and back on which resets the burner control. Much the same as you did with the fuse. If you leave your T-stat switch in the ON position and even if you move the T-stat set temp to lowest position, the furnace with still attempt to fire up. With LP off it is going to trip off on safety. This is what I am gathering from your comments above. Always turn the T-stat power to off if you are not using the furnace.