Robertshaw-Grayson series 7000 control valve

[davec]

Hi,

I recently purchased a vermont castings model vf25t free standing vent free LP gas stove with a robertshaw-grayson control valve. (Model 7000MRB-4-LC-LP)OK I got it at a yard sale but for 50 bucks I figured what the heck. I disassembled, cleaned and touched it up. I got everything hooked up, checked connections, etc., lit the pilot. I turned it on low, had a good flame, and it stayed on for about 3-4 minutes, then went out. I heard a valve click. Any thoughts on what could be going on? The pilot is good, all other gas applances in house are OK so the pressure is good. Maybe the thermocouple or an internal thermostat? Any suggestions out there would be helpful. Thanks, davec (1st time)

[HayZee518]

the millivolt generator is a skinny copper bulb that sits in the flame. a very small copper capillary goes from this bulb to what looks like a pellet at its end held in place by a small hex headed gland nut. this capillary has no gas inside but a fine insulated wire that goes from the tip to that bead that goes into the valve. Inside the valve is a small electromagnet with a spring and a cylindrical iron pellet and a neoprene seal. the millivolt generator when it's heated produces a measurable DC voltage around 740 millivolts. It is strong enough to actuate and hold the electromagnet within the valve open. when it loses is heat the snap you hear is the valve spring action closing the valve. I'd say replace the millivolt flame detector.

[davec]

thanks HayZee,

do you think this is an item that is easily obtainable? easy to replace?

[HayZee518]

yeah, should be no problem. the part that goes in the flame has two nuts on it so you can vary its height. the other end has a gland nut ohhh, about 3/8 " - a regular open end wrench should fit it. it may be smaller - I'm not sure. mine is 3/8" for my portable propane heater.

[HayZee518]

To view a list of the Robertshaw model numbers for valves that are being recalled, please check the scroll down menu below. If you have one of these products, please call our recall hotline at 1-800-232-9389, or register for the recall online. Please note that some original equipment manufacturers may not be represented. To confirm whether or not your valve model is affected, please check the valve label for the Robertshaw model number. Affected model numbers can be seen in the drop down list below next to the sample label. Please note that any millivolt natural gas valves with date codes between 0306 and 0436 that have been converted to LP fuel are also included in the recall.
this is a list from robertshaw about recalled gas valves.

[HayZee518]

go to the robertshaw site with your model number to find this list.

[davec]

HayZee,

Thanks, not on the recall list..too old...1995
Will investigate the thermo couple and ODS

davec

[davec]

hayzee,

Took apart the pilot assembly and found the small screen in the inlet side was bent over on itself. also took the other end apart and the small orifice (maybe .010") was dirty. blew it out reassembled, and the pilot has been on for an hour or so already...so thats good. thanks again

davec

[HayZee518]

I'm glad that what little we contribute will help you out. Now if I can get my car to stop overheating we'll be on second street!

[davec]

check the thermostat, flush the radiator...thats my little contribution