| Is there a new furnace in our future? [message #287294] |
Mon, 14 September 2015 20:31  |
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JShot
Messages: 485
Registered: October 2006
Location: NW Ohio
Karma: 0
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Senior Member |
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Today I tested the furnace in our coach. Haven't used it in over a year. It's a Suburban set on the angle with the two vertical holes to the outside. It has worked just fine before.
I opened the propane gas tank main valve, and upped the thermostat. Blower came on and in a few seconds, I had heat.
I shut the t-stat off, and the furnace stopped. It wasn't on long enough to keep the blower running after shut down.
I THEN shut off the valve on the propane tank.
A few minutes later as I was walking by the driver's side of the coach, I noticed a propane odor (I know, propane doesn't smell). I sniffed by the two holes in the coach side, and that's where it was coming from. The odor continued for about 10 minutes. Again the main tank valve was off. There was no odor in the coach.
So, do I have a leaking furnace gas valve? Can it be repaired? can I replace it? Or what??
Opinions?
Thanks,
John
John Shotwell
Ridgeville Corners, OH
78 Royale Center Kitchen
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| Re: Is there a new furnace in our future? [message #287295 is a reply to message #287294] |
Mon, 14 September 2015 20:39  |
77Royale
Messages: 461
Registered: June 2014
Location: Mid Michigan
Karma: 6
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Senior Member |
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Could have been that there was some unburned gas in the combustion chamber after the line was closed. My understanding is when the furnace gets hot enough and you shut it down, the fan continues to run to let the burner and heat exchanger cool down a bit, and to also vent off any offending odors and unspent gas.
Could / should test it with a sniffer with all the valves off. but also you could leave the valve to the furnace open, and the main gas valve open, Everything else gas related shut off and see if you have any appreciable drop in LP readings after a few hours or still smell gas.
Bubble soap the connections just to make sure nothing vibrated loose?
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
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| Re: [GMCnet] Is there a new furnace in our future? [message #287296 is a reply to message #287294] |
Mon, 14 September 2015 20:49 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Senior Member |
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On Sep 14, 2015, at 9:31 PM, John Shotwell wrote:
> A few minutes later as I was walking by the driver's side of the coach, I noticed a propane odor (I know, propane doesn't smell). I sniffed by the two holes in the coach side, and that's where it was coming from. The odor continued for about 10 minutes. Again the main tank valve was off. There was no odor in the coach.
>
> So, do I have a leaking furnace gas valve? Can it be repaired? can I replace it? Or what??
Even after you shut off the tank valve there is still a small inventory of propane under pressure between the tank valve and the appliance valves. Naturally if you command the furnace to run after the tank has been turned off the furnace will open its valve and try to ignite what is there and if it cannot light then raw propane will come out the exhaust hole for a short amount of time until the supply line has emptied.
The human nose is extremely sensitive to sulfur mercaptans - that is why those compounds were chosen to odorize propane and natural gas - and only a miniscule amount of them will result in a detectable smell. Did the smell coming out of the exhaust hole subside and not return?
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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