WH on garage floor

John Mills_5

Plumber replaced a gas water heater in a customer's house. Put it on the garage floor. Told her that the new design means they no longer need to be 18" up. That true? 

Jean-David Beyer

I will tell you what I know.

I am just a homeowner, and I have a mod-con in my garage. I got an installation manual for it of fthe web and it said if it is located in a garage, it must be 18 inches up from the floor. My old oil fired boiler was flat on the floor. So when my former contractor was installing it, they put the new one on the floor. I asked why they were doing that since the Installation manual said specifically that it had to be 18 inches up. The explanation was that the boiler had a sealed combustion system (true) that got its air from outside and exhausted directly to the outside (also true), so any combustable vapors in the garage would not be sucked into the boiler itself. Furthermore, they said that the air intake to the burner was actually over 18 inches from the floor (it may be a little less than that). I have my doubts about my former contractor. I do not think it is much of a safety problem because their explanations are mostly true. Unless the gasket between the front door of the boiler and the rest of it leak rapidly, I would not expect much gasoline vapor to get in there. When they were done, the inspectors did not have a problem with it. But that inspector also allowed an ungrounded unbonded piece of CSST gas pipe. But even though it passed, I bet is is not according to code.

Ironman

Not True

Unless it's direct vent, the burner must be 18 in off the floor. I don't have time at the moment to pull up the code reference, but we covered that in gas code class last week.

billtwocase

or if not

you can build a vapor barrier around it with blocks and cement, but 18"  off the floor is the norm.

meplumber

NFPA 54

9.1.10.1 tells us that the appliance installed in a Residential garage must be 18 inches off the floor unless specifically listed as 'Flammable Vapor Ignition Resistant."



There is a huge difference in a Residential Garage and a Repair Garage where the requirements a long and distinguished.

Robert O'Connor_12

Elevation of ignition source

Elevation of the ignition source is not required for appliances that are listed as flammable vapor ignition resistant (FVIR).

Robert O'Connor/NJ

Jean-David Beyer

Mine is direct vent, but

Mine is direct vent, but the installation manual says it must be 18" off the garage floor. (Weil McLain Ultra 3.) Are they being overcautious, or do they know something that I do not (easily possible).

John Mills_5

THANKS

for the information. At least the plumber was right about that. Now his 3x4" flue transition which was just a 4" over a 3" and mashed down and his PVC pop off piping...