CHI2 Posted July 20, 2010 Report Share Posted July 20, 2010 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. Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted July 20, 2010 Report Share Posted July 20, 2010 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. Quote Link to comment Share on other sites More sharing options...
CHI2 Posted July 20, 2010 Author Report Share Posted July 20, 2010 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?? Quote Link to comment Share on other sites More sharing options...
Marc Posted July 20, 2010 Report Share Posted July 20, 2010 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 Quote Link to comment Share on other sites More sharing options...
Tom Raymond Posted July 20, 2010 Report Share Posted July 20, 2010 Could be worse, it could be a gas appliance running on propane. The flame looks like straight acetylene and creates about as much soot. Quote Link to comment Share on other sites More sharing options...
RobC Posted July 20, 2010 Report Share Posted July 20, 2010 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. Quote Link to comment Share on other sites More sharing options...
hausdok Posted July 20, 2010 Report Share Posted July 20, 2010 Maybe the installer modified it so that it can properly burn natural gas. OT - OF!!! M. Quote Link to comment Share on other sites More sharing options...
Erby Posted July 20, 2010 Report Share Posted July 20, 2010 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. - Quote Link to comment Share on other sites More sharing options...
RobC Posted July 20, 2010 Report Share Posted July 20, 2010 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. Quote Link to comment Share on other sites More sharing options...
Greg Booth Posted July 20, 2010 Report Share Posted July 20, 2010 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. Quote Link to comment Share on other sites More sharing options...
Jack Ahern Posted July 21, 2010 Report Share Posted July 21, 2010 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] Quote Link to comment Share on other sites More sharing options...
CHI2 Posted July 21, 2010 Author Report Share Posted July 21, 2010 This one certainly wasn't labled as a converted unit, however appeared to be working ok. I called for a licensed plumber to take a look and convert to natural gas or replace as needed. Thanks! Quote Link to comment Share on other sites More sharing options...
Charlie R Posted July 22, 2010 Report Share Posted July 22, 2010 Good call. Quote Link to comment Share on other sites More sharing options...
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