View Full Version : How to bleed air out of gas pipes?
doityurselfer
Oct 25, 2011, 08:48 PM
I had my gas turned on, after being shut off for several months. I have a gas water heater and a gas floor furnace. I was able to disconnect the gas line from the water heater, open the valve for a second or two and bled the air out. I was then able to get the pilot lit, now my water heater works fine. However, my furnace is not so easy. I have had the pilot button clamped down for 6-8 hours, trying every hour to light the pilot--to no avail! Where the gas line feeds into the furnace is in a verry tight crawl space. There is a shut-off valve in the line just preceding the furnace. But, there is a union just before that in the gas line. How is the best way to bleed the air out of the gas line?
afaroo
Oct 26, 2011, 08:01 AM
Turn on the burner by holding a lit lighter over the burner until it lights off. Now light the pilot light and that takes care of it, if you're uncomfortable with that call in a professional, Thanks.
John
doityurselfer
Oct 26, 2011, 08:22 AM
The burner won't turn on unless the pilot heats up the thermocouple. That won't work. But thanks anyway.
massplumber2008
Oct 26, 2011, 01:36 PM
Hi DIYr
Break the union using two wrenches and bleed the gas through that until you smell gas (3-5 seconds) and then tighten the union back up using two wrenches. Then, holding the pilot button in as you have been doing try to light the pilot... could still take 30 seconds to bleed any residual air between the union and the gas valve... should work.
If that fails to get it all lit up then your THERMOCOUPLE could be shot and it may need to be replaced!
Good luck!
Mark
afaroo
Oct 27, 2011, 07:32 AM
Hello Doityurselfer,
I tried to help you and gave you my openion you didn't have to gave me a negative review, Thanks.
John