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Nosiy motor on gas furnace

Post in 'DIY and General non-hearth advice' started by maryjones, Sep 14, 2007.

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  1. maryjones

    maryjones New Member

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    I just moved into a new house where the gas furnace and water heater are located in an unfinished dirt basement. I just noticed my gas furnace sounds as if a 747 was landing in my living room when it turns on.

    I called the gas company guy and he said the equipment is fine but because this house didn't have a chimney a motor was installed on the furnace to vent the (fumes, air?) out of the house and the motor is noisy. Plus he thought the two plastic pipes doing the venting were vibrating against the plywood encasement. He suggested insulating my floors and moving the pipes a bit.

    Has anybody had a similar experience? Is there an alternative way to vent one of these beasts? Do these things really have to be so noisy or do I have a cheap motor.

    Who else might I ring to solve this problem. My other house didn't have insulated floors and it was pretty quiet. Of course those were wooden floors and this house has pergo.

    Any advice--especially who to call would be great.

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  2. Eric Johnson

    Eric Johnson Mod Emeritus

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    Could be any number of things including, as you suggest, a cheap blower that will never run quiet.

    One thing I would check would be the blower blades themselves. It's probably some kind of a "squirrel cage" arrangement. If the blades have become loaded with dirt and other debris, the blower will be out of balance and will vibrate. After shutting OFF the circuit to the blower, clean off any crap that has accumulated with a brush or Q-tips. You should also go down there and move the piping around when the thing is running, so that you can isolate any vibration. And getting back to balancing, if the blower mounting nuts are not tightened down uniformly, the whole motor could be out of balance and vibrating. Fool around with the mounting bolts when the thing is running and see if you can increase or decrease the vibration.

    If this sounds like something beyond your capabilities, then you should call a heating professional and have it checked out. If it's "new" new, then whoever installed it should make it right. If it's been around for awhile, it may need lubrication. Some motors can be lubricated and others can't. If there's a place to put oil (it should be clearly marked as such), then a couple drops of multi-purpose oil might be worth a try. I'd try that last, and don't do it if you're not sure what you're doing.
  3. tutu_sue

    tutu_sue New Member

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    We had the same thing when we moved into our house. We have a direct vented boiler. Once we oiled the motor, it quieted right up. I downloaded the boiler manual from the manufacturer's web site for instructions and how often to oil. Oiling is required more often than we thought. Good luck.
  4. maryjones

    maryjones New Member

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    Thanks to both--advice makes sense. Will post my result.
  5. drizler

    drizler Minister of Fire

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    You know something, that could be perfectly normal. I remember the gas furnace in my parents place in Florida some years back as well as a couple others who had mobile homes. Those furnaces can make one hell of a racket if they are placed in or near living or sleeping quarters. That could be what you are experiencing. That goes double if you are used to something quiet like electric baseboards. The power vent would just add slightly to it all. The mobile home sort like miller really do make a lot of noise with their not having much insulation. Take a gander at it running and listen for the power vent and blower fan running. If they aren't squealing then they probably are ok and insulation might be your answer. One thing to consider also. Like my pellet stove running, in time you get used to turning up the tv and eventually won't notice it. I would give that a crack if it's new to you and see how you live with it before you start plowing lots of bucks into it. If you do need an electric motor don't buy one from the local furnace guy or plumbing supply. Instead look for the mom and pop shop that fixes electric motors. I doubt they will fix it but the replacement price is about 70% of what you pay from the heating guy or plumber. Maby more like 50% like when I did the miller furnace blower in my rental trailer.
  6. Eric Johnson

    Eric Johnson Mod Emeritus

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    Or, just Google the model number of the motor and/or blower and you'll find the best price online.
  7. Gooserider

    Gooserider Mod Emeritus

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    You might also try wiggling the air intake and exhaust pipes a bit, see if that changes anything - they may be hitting on something, and you might be able to either tweak them away, or jam a bit of insulation or rubber foam like they insulate hot water pipes with between the pipe and what its hitting on and dampen the vibration. If just putting your hand on the pipes quiets them down, you might try putting a better support under them - anything that would change the resonant frequency of the system might help.

    Gooserider
  8. jtp10181

    jtp10181 Minister of Fire

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    I had a similar situation with the forced air blower on my furnace. Due to lack of maintenece the bearings dried up and it started grinding away at the rod and other parts, which was very noisy. I had to replace the squirrel cage motor. The new one I got has little plugs to oil it so I put a few drops in there once a year. The old motor had no way to oil it anyway so I don't see how they expected anyone to service it, unless you take the whole case off the thing and oil it like that (which is a PITA).
  9. drizler

    drizler Minister of Fire

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    None of mine were ever serviceable in any way. They did last for many many years with no problems. No problem with longevity here. The reason I said an electric shop and not the net is getting one TO FIT. While the sizes are somewhat standard it can be a shot in the dark to match something up. I buy most stuff over the net but still there are times when you need it in your hot little hand showing it to someone who truly knows his stuff. In the case of my old blower motor in the Miller No one seemed to have it without a 200 to 300 price tag because it was in a trailer. Trailer is a very dirty word you know. By going to the mom and pop electric supply I walked out of there with a slightly more powerful Dayton for something like 130 and it fit right in. Of course your mileage may vary but its hard to argue with a deal like that one. In my case I do most of my own electric but don't trust myself with "changing things" to more powerfulif I can help it.
  10. weistk

    weistk New Member

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    Maybe this will help, my friend had same problem, it turned out that the housing on his fan for combustion venting (plastic) warped from heat and contacted fan hub causing the noise.

    Good luck,
    Weistk
  11. fbelec

    fbelec Minister of Fire

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    by the way, there are two different types of venting. a built in power venter that is vented via pvc piping. 2 to 3 inches in diameter. those don't get to hot if you have to support or jam something between the pipe and joist. they get about 80 degrees hot give or take 10 depending on how close you are the heater.
    then there is the external type that are mounted on the inside of the house just before it goes outside. the pipe is not pvc but regular galv metal smoke pipe. 6 or 7 inch in diameter. those are usually noisy, nothing can be done unless the fan has buildup on it like what was said earlier. this type of power venter the pipe going into the fan unit between the venter and the heater regardless of the type of fuel gas or oil gets hot. hot enough to melt something that can't take heat so be careful.
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