Maximum BTU/hr with 3/4-inch black pipe?

Steve Garson_2

My 115K BTU gas boiler is fed with a 3/4-inch gas pipe. I would like to install an instantaneous gas water heater that will provide 4-GPM, but wonder if the gas pipe will support the two.

Will this work? Or will the load be too large for the pipe?

EBEBRATT-Ed

No. Probably not even close. What other gas appliances do you have? What size is the pipe coming off the meter?

ratio

See attached. (Need to know the length as well.)

Jamie Hall

You need the input rating of that water heater. It will be at least 130,000 BTUh and possibly as high as 200,000 BTUh.

ChrisJ

With normal gas pressures not even close.

at 2 PSIG with a pressure regulator at each appliance, probably.

Matt_67

Is it natural gas or LP gas?

The Steam Whisperer

Potentially you'll need to upgrade your gas service too. You should also check if these instantaneous units are banned in your area. They are causing problems because they use gas so quickly that the gas network can't keep up if too many of them are installed. They all turn on about the same time everyday in many areas( ie morning showers, etc.)