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JMH3
Propane Hot Water Heater Pilot Light Issue

Hi Folks!

I have a problem with a brand new propane gas mobile home water heater that is in a closet inside with about a 3" vent pipe coming up thru the floor that was fixed to the bottom of the old heater with a collar.
I lit it then and it worked ok but when I got home after work the water was cold and the pilot was out. I lit it again easily on the first click and it heated to the 120 mark I set it at.
Next morning it was out again, recurring problem.
I wonder if there is too much air coming in the vent and blew the pilot out or if there is a setting issue with it.
It's a US Craftmaster sold at Lowes, Model MFG1F4040T3PV7K.
It has a draft hood on top that I had to bend the feet down on so it would fit under the top vent pipe, there is 1/2" or more of space between the top of the heater and the draft hood to allow air to come in.
When the burner fires up it's pretty loud, louder than it should be in my opinion.
Any ideas? Thanks! John

JMH3
Re: Propane Hot Water Heater Pilot Light Issue

OK, I bent the feet back down and put the thing on like it shows in the picture. That gives 1" or so between the top of the heater and the vent pipe. Should I also cover that vent pipe coming thru the floor? The model I have has a screen on the bottom.
Thanks for your help!

JMH3
Re: Propane Hot Water Heater Pilot Light Issue

OK, I meant the top of the heater and the bottom of the draft hood, it's set on the heater as per the photo in the FVIR link and connected to the vent pipe. The 3" vent pipe coming thru the floor should be left open? It feels pretty breezy coming up thru there.

JMH3
Re: Propane Hot Water Heater Pilot Light Issue

Funny thing is, they included an additional burner with the heater.The card on the front of the heater that has Model & Serial # etc., says it's equipped specifically for LPG gas. There is nothing in the manual/users guide that explains why there was an additional burner included in the box. The burner has no info on it either.
After installing the vent hood correctly the pilot seems to be working ok, it was still on, I took a shower, washed some dishes and it drew down enough to fire up, same loud boom when it did.
That burner firing up is louder than I have heard before, what can be causing that?

goldhiller
Re: Propane Hot Water Heater Pilot Light Issue
JMH3 wrote:

same loud boom when it did.
That burner firing up is louder than I have heard before, what can be causing that?

Sounds to me (from afar) that although the unit says it ready for LP....they didn't change out the burner supply orifice to the LP (smaller size orifice compared to NG because LP is delivered at a higher psi than NG). If so, this larger NG orifice would allow too much gas to enter too fast. IOW, too much un-ignited gas builds up too fast and when it finally does ignite (via the pilot light).....kaboom. This would also explain a louder "roar" you hear from the burner when it is up and running. Too much gas.

A faulty (or mis-adjusted) main pressure regulator on the LP line into the house can also cause this issue of too much/too fast gas delivery. This *might* be the problem, but would almost seem to be too coincidental that it would happen at the exact same time that you changed out the WH. It could happen though, just seems unlikely.

Also....there is a small round screened vent port on the bottom of that main pressure regulator....which is usually located against the side of the house where the gas line enters. This vent port can become clogged with snow,frost,bugs,air-borne dirt, etc. If it is, it can/will cause erratic behavior as regards gas pressure regulation. Doesn't take but a minute to go out and make sure it's not clogged.

I suspect it's an issue that the unit didn't get converted over to LP properly though. The larger NG orifices are still in place....me thinks. It's a SWAG from afar, but there you have it.

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