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Furnace Blower Replacement

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Bad juju the fan HAS to run first it is called a pre purge. There should be no attempt to light until the fan has proved there is a device call a sail switch that the fan blows closed nothing should happen until the sail switch closes or things could go boom. It is possible the sail switch is toes up but until it runs first you need to turn the gas off. Even if the fan is bad the gas valve should not open if there is no airflow absolutely nothing should happen. I don't mean to be an alarmist but you got a dangerous situation there if your statement is correct. When the t stat calls for heat the fan runs first no exceptions then the frunace lights. 

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Interesting.... Ok, is it possible I am just feeling heat from the pilot light? I can't imagine that would be the case. Not sure of the make /model, I will post when I get home. So just to be sure I understand... If all was working correctly, when I go to light the furnace, after holding the pilot light knob down for 30 seconds and then turning the knob to "on" the fan should kick on automatically no matter where the thermostat is set at? 

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OK we need the make and model. If you have a standing pilot light heater the rules are different. But in any case the thermostat turns on the fan.

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 Ok, for some reason it won't let me upload pictures. Frustrating. It is a hydroflame HF 8012. Model suffix P, 12000 btu, 59 DMS, 12 volt, 1.6 amps, 19.2 amps

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Instructions...http://bryantrv.com/docs2/docs/operating/hflame8012.pdf

If your actually getting the heater flame on then you have major problems. IF the heat your feeling is just from the pilot light then you may have a couple of semi-major problems.

1. Dirty sail switch clean and lube till it works easily

2. Replace or clean and lube the fan motor. This is probably your main problem.  If you try clean and lube don't use WD-40 or 3 n 1 oil use a good 5-20 synthetic auto oil

This is NOT the correct one for your heater, but this is what a new one looks like. You will need to remove yours and head to an RV store to see what they can do for you. Try googling the PN on your blower and see if there is a sub.  http://www.ebay.com/itm/Atwood-Hydro-Flame-RV-Furnace-Heater-37698-Blower-Motor/192060533961?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D20131003132420%26meid%3Da92677d03b5b47fe813700bfedf89dc1%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D182369584807&_trksid=p2047675.c100005.m1851

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So, I started thinking that maybe the auxiliary battery didn't have enough juice in it to run the motor. I started the car engine and the fan started. Not sure why it started because everything is still wired the same way and it never turned on before. So since it was running I turned on the propane and began the checklist for starting the furnace. As I was waiting the 5 minutes with the thermostat on high the motor started slowing down and within 3 minutes stopped.  I am so confused...

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If you can plug the RV into the house it will help the trouble shooting and save engine wear.

Still sounds like dry fan motor bearings.

Parts diagram...http://www.atwoodmobile.com/manuals/furnaces/FurnaceExplodedViewsandPartsList.pdf

Part source...http://68.171.35.13/hydroflame-furnace-parts.html

 

 

 

 

 

 

 

 

 

 

 

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When the fan was blowing it was making squealing like noises for about 30 seconds and then was very smooth and quiet for the other 5 mins. Does that still sound like the motor bearings? 

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OK confusion on my part. One post you said the motor started and ran for 3 min, then slowed down and stopped.  Then you said it squealed and then ran for 5 min.. Have you ran it multiple times?? or what is it doing.

First is bad fan motor/weak battery. Second is bad fan motor

Most of the contacts are sealed. But the ground is usually a screw some where to the chassis and the positive is a bolt connector. Find them and redo them. A voltmeter is real handy about this point, it will let you check the voltages through out the entire system and make it all good. Point being when I got my Escaper the isolator voltage was 14v + , the house battery voltage was under 11.5v. The P/O had spliced wire to many places and did a poor job. Replace all the battery charge wire mess and ended up wilt 13.8v at the battery.

Low voltage will make a heater run bad or not at all.

 

 

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