Robert Shaw Unitrol LP Gas Valve - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 11-22-2011, 05:27 PM   #1
Mechanical Contractor
 
Join Date: Nov 2011
Location: Tijeras, New Mexico, USA
Posts: 3
Rewards Points: 10
Default

Robert Shaw Unitrol LP Gas Valve


Does anyone know what the nominal ohm value of a good coil (with all conductors removed) would be?
Ballpark Range

What is the nominal voltage Mv required to open main gas valve. Pilot is on.
All other associated switch and safeties have been tested for proper operation

Thanks,

Bobby K
Tijeras,NM

Advertisement

Bobby K is offline   Reply With Quote
Old 11-22-2011, 05:38 PM   #2
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,034
Rewards Points: 706
Default

Robert Shaw Unitrol LP Gas Valve


400 millivolts minimum but most of the time you need at least 500-600 from the generator (unloaded)due to the wiring and connections/loss etc.

Advertisement

__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 11-22-2011, 06:19 PM   #3
Mechanical Contractor
 
Join Date: Nov 2011
Location: Tijeras, New Mexico, USA
Posts: 3
Rewards Points: 10
Default

Robert Shaw Unitrol LP Gas Valve


Yuri,
Thank you for your answer. I will be installing a new T-Pile this evening, i will record its resistance and maximum MV generated at start up.
Any thoughts on the ohm value of the gas valve?

Happy Thanksgiving

Bobby K
Bobby K is offline   Reply With Quote
Old 11-22-2011, 06:43 PM   #4
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,034
Rewards Points: 706
Default

Robert Shaw Unitrol LP Gas Valve


Make sure the pilot burner is clean/clean orifice so that the flame surrounds the generator properly. After that it should produce 700 or more Mv when new. I worked on hundreds of those old units back in the day and never ohmed the gas valve. 99% of the problems are weak generator, dirty pilot, loose wiring connections, corroded connections on the valve or bad tstat. Must have absolutely bare copper wire when making connections on millivolt systems. Gas valves usually just die and stick closed.

On some of those universal generators there is a brass sleeve (Honeywells) and it can rob heat from the generator and needs shortening if using in a PG9 pilot burner to replace the fat PG9 which is not available or very hard to find.
__________________
"Cut it twice and it is still too short".

Last edited by yuri; 11-22-2011 at 06:46 PM.
yuri is online now   Reply With Quote
Old 11-22-2011, 07:21 PM   #5
Mechanical Contractor
 
Join Date: Nov 2011
Location: Tijeras, New Mexico, USA
Posts: 3
Rewards Points: 10
Default

Robert Shaw Unitrol LP Gas Valve


You Da Man,
Thanks again, I'll let you know how things turn out
Bobby K is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to diagnose gas valve problems Nestor_Kelebay How To Guides 28 10-30-2013 05:19 PM
pressure relief valve is leaking on boiler wlmpdiycr HVAC 65 10-26-2011 06:00 PM
Remove Robert Shaw D34000 Thermostat? wanderlust HVAC 7 10-11-2011 05:27 PM
Best 1/2 inch water shut off valve. Nestor_Kelebay Plumbing 10 07-25-2008 12:16 PM




Top of Page | View New Posts