Sticking Robertshaw gas valve

Old 03-06-08, 11:28 AM
Thread Starter
Join Date: Mar 2008
Location: California
Posts: 7
Received 0 Votes on 0 Posts
Sticking Robertshaw gas valve

I have an old Sears wall furnace with a replacement RobertShaw 7000 series gas valve (not one of the ones that were recalled). In the morning lately the furnace won't ignite. The pilot light is on, I replaced the thermocouple last year, and if I bang on the gas valve the furnace will ignite. Usually in one hard knock, sometimes it takes a couple. So apparently something (the diaphragm?) is sticking. Is there anything I can do to fix this other than replace the valve?
Old 03-06-08, 12:41 PM
pflor's Avatar
Join Date: Dec 2007
Location: U.S.A.
Posts: 1,127
Received 0 Votes on 0 Posts
the valve should be replaced
Old 03-06-08, 03:14 PM
Join Date: Jul 2005
Location: New York
Posts: 723
Received 0 Votes on 0 Posts
There is no way to repair the gas valve so as pflor said it will need to be replaced.

However, before doing that I would check the voltage at the gas control valve to assure you have sufficient voltage to open it. Depending on if it's a 24 volt system or a millivolt system will be dependent on the proper voltage at the gas control to open it. If it's a 24 volt system, you should have approximately 25 volts at the gas control for a call to heat. If you have a millivolt system, with a thermopile, you should have a minimum of 500 mv (millivolts) but 750 mv is ideal.
Old 03-08-08, 09:53 AM
boilersrus's Avatar
Join Date: Nov 2007
Location: Long Island, NY
Posts: 313
Received 0 Votes on 0 Posts
Not to hijack any body's reply, but also check the connections on the gas valve too. You can remove them (if they are spade connections) and put them on and off a few times to clean the contact surfaces. They should be nice and snug. If there are any wire nut connections on any of the gas valve feeds I would double check those connections too.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: