Natural Gas Fireplace Burning Propane...how bad?

[MrBailey]

How bad is it to have a fireplace configured for natural gas actually burning propane?

The reason I ask....

Recently moved into a new construction house with a gas fireplace, which is connected to a LP tank. There are two D cell batteries as backup for power loss. A wall switch turns it on/off.

It was working fine for the 5 or 6 times we used it. Then it stopped working.

The fireplace company (under warranty) came out to take a look. They found:
1) The fireplace was never wired for house electricity. It was working solely off the batteries.
2) The fireplace was NOT configured for propane, but was still factory set for natural gas.

They fixed the second issue and plugged the system temporarily into a nearby outlet. Will have to wait for an electrician, under warranty, to wire it properly.

Thanks in advance.

Bailey

 

[NetWareHead]

The orifice in the fuel line that feeds the burner is larger in natural gas then propane (for the same BTU output). If you feed propane through a natural gas spec'ed appliance, you will overfire it.

 

[MrBailey]

Well, I'd have to say...as hindsight. The flame did look large, regardless of the setting (hi to low).

 

[NL5]

It's not about the size of the flame, it's the heat output. As stated above, lp needs a smaller venturi do maintain proper heat levels. Whoever installed it really screwed the pooch.

 

[NetWareHead]

Also propane is regulated to a higher gas pressure than natural gas. Higher BTU output fuel combined with higher than expected pressure will definitely overfire. Does your fireplace have a pilot flame? Maybe the pilot was overfired too. The thermocouple/thermopile that hangs out in the flame all day saw higher than normal temperatures. Wouldn't be surprised if it failed sooner.

 

[MrBailey]

It turns out, more than one house in our development had the issue. Someone even reported their water heater (on LP) was still setup for natural gas.

 

[highland145]

Can you just change the orifice? My life isn't usually that simple but...

 

[MrBailey]

For our case, that's what was done. They changed out the system, cleaned, and made sure everything worked properly.

It was pretty obvious they (the fireplace company) supplied the fireplace unit to the builder, but the builder had one of his workers install it.

Oh, well. New homes have their issues too...although they shouldn't.