Tankless Water Heaters Problems And Reviews

Question: What is proper size natural gas pipe for tankless water heater w. max input of 185,000 btu?

(Posted by: Morgan Morgan on 2010-02-05 10:55:26)

Line from utility to meter is 3/ 4 ". Line to house starts with short length of 1 ", then reduces to 3/ 4 ". run of pipe frm service to heater aprox. 50', with 8 elbows/ tees. There is already a 1 " line under house, off of 3/ 4 " from meter, to spa heater in back yard. If I need 1'' for heater, can I tee off existing 1 " line, or am I limited by 3/ 4' from meter. length of run from possible tee is aprx. 25', with 2 elbows, to flex line to heater.

Posted by: Jonathan on 2010-02-05, 19:53:14

The problem with teeing off existing line will be that most likely you cannot run both heaters at the same time...

Posted by: Rondi on 2010-02-05, 13:25:17

Your pressure will remain the same irregardless of volume or size of pipe. Tee off the 1 " to your 1 " inlet on your tankless. Your primary concern should be volume of water to the tankless and the proper back pressure. A tankless will not work with a big umbrella shower head.