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Confused LP water heater


CHI2
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Maybe I'm missing something here. Inspected a home today with an LP water heater. Big black stamp LP on the manufactures' label. The valve was also an LP valve, however the home was serviced with natural gas.

The gas pipe went to the furnace which was natural gas and the water heater that was stamped with the LP notice....

Am I crazy or can this possibly work? The water heater was operating when we were there.

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Man. Just when you think you've seen it all. The home was built in 1984 yet the water heater was new. I can't believe someone would install an LP unit like that. Home was pretty clean too. Seems like someone wasn't paying attention??

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Nat. gas operates at a lower pressure than LP, so nat. gas appliance orifices are larger than LP orifices. An LP appliance running on natural gas will likely have very tiny flames.

Isn't the optimum air/fuel ratio different also? Wrong jet yields the wrong ratio which then yields yellow trim on the flames and unoxidized fuel going up the flue.

Marc

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Maybe I'm missing something here. Inspected a home today with an LP water heater. Big black stamp LP on the manufactures' label. The valve was also an LP valve, however the home was serviced with natural gas.

The gas pipe went to the furnace which was natural gas and the water heater that was stamped with the LP notice....

Am I crazy or can this possibly work? The water heater was operating when we were there.

I had a similar situation years ago with an LP rated furnace installed in a garage hooked up to natural gas.

I was told by the gas authority that the calorific values of LP is 2.5 times that of natural gas (LP burns hotter). So a gas appliance on LP will over-fire that could result in an explosion.

Conversely, an LP appliance on natural gas will under-fire.

You might want to contact your AHJ for their ruling on thsi. I wouldn't be surprised if they demand the appliance be replaced.

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May not matter on a circular burner but a furnace burner needs a different slope for the different fuels.

LP runs downhill - Natural gas runs uphill. Or is it the opposite?

Convertible units exist but are "supposed to be" clearly labeled as having been converted from one to the other.

-

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May not matter on a circular burner but a furnace burner needs a different slope for the different fuels.

LP runs downhill - Natural gas runs uphill. Or is it the opposite?

Convertible units exist but are "supposed to be" clearly labeled as having been converted from one to the other.

-

Propane vehicles are not allowed in underground parking - LP flows downhill.

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Pretty simple to convert. Furnace requires specific orifices for burner and pilot (if not hot surface ignition). Water heater similar. Also need to alter pressure control on valve, which many times simply requires a reverse of screw-in insert. In the manufactured home industry, units almost always are shipped set for natural gas, and include propane orifices to facilitate changeover.. As mentioned above, one should always clearly label whatever fuel the device is being set-up to operate on.

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Outfitted my Maine house with Nat Gas appliances (modified per instructions). Purchased the stuff in Mass. Modified in Maine. Works great. (Sharpie fine point) conv.date written on/near appliance.

Boston Plumbing Inspector eyeballed arrangement-----OK!

Business is sloooooooooooooooooow![:-party]

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