LP water heater hooked up to NG

[Brian Ramirez]

Does anyone have any information on a LP water heater converter to allow hook up to a NG line?

[Bob Harper]

You can perform a a field fuel conversion only if you use the listed kit from the mfr and you get that only if they allow it (most do). You must change the burner orifice spud, pilot orifice spud, pressure regulator on the combination valve, air shutter setting, possibly the entire burner itself, and install a sticker noting the conversion, by whom, what the new orifice size is, manifold pressure, BTU/ hr. input rating, date and sign (nobody signs them). Going from NG to LP usually isn't a problem with existing gas lines but LP to Nat might be if they sized it closely. More LP flows through the same size gas line as NG on a BTU/ hr basis so the same amt. of BTUs can be delivered through a smaller line for LP than NG.

As for drilling out orifices, it is not recognized in the codes and if it is found to have caused a problem, somebody will be hung for it. Orifices are precision holes. Even if you locate the proper size drill bit, what do you have to keep them perfectly aligned? Hand drilling is notoriously bad. I used to do it until I learned better. I did note an increase in callbacks for sooting or noisy burners on units we had drilled the orifice out.

FYI, not everyone uses the D.M.S. drill gauge system for orifices. HHT uses DMS ( which you may recognize as "wire gauge', decimal ( Heatilator) or metric ( some Heat & Glo). If you contact Andersen-Forrestor, you can get more info. on orifices and gauging sets. They sell kits with a "drill index", which is the thing with all the holes in it that keeps all those tiny bits in their proper places. I have one set that has hex shanks stamped but most round bits are unmarked and would need a index plate to determine the size.

HTH,
Bob