Like Bob, I work in the states he mentioned (MA, RI)
I too don't understand why this would be required for a gas furnace, as the gas valve allready has a safety device built in. These devices aren't required above gas-fired water heaters or other gas fired appliances, so why would a furnace need one?
I have always installed them due to tradition but I won't anymore if I can find the applicable code references.
Also, the safety switch often installed at the top of the basement stairs or just outside the boiler room is another one that confuses me.
The firomatic requirement for an oil burner makes sense though, and is always done around here.
Peter
