Air blowing from flame inspection port


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Old 02-26-08, 03:45 PM
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Air blowing from flame inspection port

I have a 25 year old mobile home with an Intertherm (Model MSH 065 AB) oil heater. I cleaned it today and noticed that when the blower fan is on it blows ALOT of air out of the flame inspection door when opened. I don't know if it's always been like that or if that's how it's supposed to be?? I never smell any fumes or anything in the home. The return is fed through the heater cover and it's located in the hallway. Thanks for any help you can offer!!

Jon
 
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Old 02-26-08, 07:00 PM
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Air

When the burner is running & you put your hand in front of the peep hole, do you feel a good bit of heat? If so, either the heat exchanger is crapped up with rust or soot OR the heat exchanger is shot. These furnaces are bad about rusting out near where the vent pipe connects. The average life expectancy for a mobile home furnace is about 15 years.
 
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Old 02-27-08, 04:17 AM
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I do feel some heat coming out. I got to thinking... the heater sits directly over the vent line that's runs up and down the length of the trailer, isn't the air supposed to blow around the heat chamber and then down through the bottom into the vent line? Is it possible this is the way it's designed?
 
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Old 02-27-08, 05:06 AM
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Other than an occsional downburst of wind through the flue pipe you shouldn't have anything. If you can feel air blowing out the inspection door with the blower on then the heat exchanger is cracked/rusted and shot.

This is assuming you didn't have a bathroom vent fan or something going when you opened it to check ...but since you said it is a lot of air it is probably cracked. Prop it open and check with the blower on and off to verify, but sounds like you need to cut the gas off to the thing and get it replaced.

...oh, if the furnace is still burning well you may NOT smell any fumes in the home, you just might wake up dead...and that'll ruin the day!

Michael
 
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Old 02-27-08, 05:15 AM
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Can you get a heat exchanger for an Intertherm like this and if so is it worth it to change it? I am laid off for another 2 months and don't have money for a new heater.
 
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Old 02-27-08, 02:55 PM
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Heat Exchanger

At 25 years old, it's doubtful you can get a heat exchanger for that furnace. Even if you could, it would probably cost more to replace than a new furnace.
 
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Old 02-27-08, 03:20 PM
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I called a technician in Indianapolis today and he said that it is normal to have air blowing out in a downdraft heater like this, he was an Intertherm dealer too. I called Intertherm and talked to tech support and they said it shouldn't do that. I guess I'll listento themajority here!
 
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Old 02-27-08, 04:57 PM
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Technician?

Did this tech actually come or just say this over the phone?
It is easy for a pro with instruments to get data which would indicate a bad heat exchanger. All that needs to be done is measure the oxygen in the upper part of the heat exchanger with the burner on & fan off. When the fan comes on, if the oxygen level changes, there's a leak in the heat exchanger somewhere. The same can be done with CO2 or CO but oxygen works better.
 
 

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