Gas and Oil Home Heating Furnaces - Identifying wire on gas control valve?

I just bought a millivolt gas control valve (Robertshaw 7000 MVRLC) to use with an old space heater, the kind that sits away from the wall. There is a wire coming from the underside of this valve(just under the gas inlet) that has a male electric connector on its end. I'd like some help figuring out where this wire should go. The valve is marked where the thermocouple(thermopile?) and thermostat wires go.

There are 5 photos of this valve and the wire at this web site:

http://webpages.charter.net/jbclem1/ . Just look for the entries named Robertshaw1 thru Robertshaw5.

I'd appreciate any help...I tried Robertshaw tech support but they won't help an enduser for liability reasons.

Regards,

John

I haven't looked at the photo yet, but if memory serves me as I had to work on this space heater with such a valve a couple years ago, I think it is a thermostat wire. I believe that is how the gas valve turns on and off with the sensing of temperature inside the heater. The thermocouple you see is actually just a safety device that makes the unit go out if the pilot light loses it's flame. But I believe the wire you speak of is for the thermostat control of the space heater itself - I think. Will anyone else here second the motion?

Tip: Robertshaw won't help you but I bet one of the retailers of floor space heaters would!

ecman1, please look at the photos and see if you still think it's a thermostat wire. I took the valve to a hardware store that had the exact same valve on display and the wire in question on that one had a female connector and plugged into a male connector on the valve body right next to the various holddown screws for the thermocouple and thermostat wires. The problem is the wire on my valve has a male connector so even though it's the identical valve to the one in the hardware store the connectors don't match up (male to male doesn't work), and this implies there is some kind of wiring difference.

There is a tag on the other side of the valve that says Manufactured for Williams Furnace Co., so perhaps Williams uses a slightly different wiring scheme. Which is what I need to find out. Unfortunately, calling Williams Furnace Co. didn't help...no sign of a tech support department.

If anyone knows about this valve and Williams space heaters, I'd sure like to hear from you.

John

It goes to a spill switch. This valve is designed to be installed on a wall furnace. I would suggest you not install any valve on the room heater you have. This is defintely a job for a dealer. More to it than just replacing valve. Input must be set and I would also check for c.o on startup. Safety first please

Why did you get the new valve? And where is the old valve and what's wrong with IT?

Can you compare the old valve to the new one to see if ratings are listed and compare?

Because one valve has a male spade and the other a female connector may be inconsequential. Then again...........per mbk3.

Oh - and where were you even able to buy that valve at? Nobody there is in a heating department that can help you with your questions? Our supply stores (that sell HVAC, plumbing, and mechanicals parts here - have heating departments, with helpful/knowledgable people that work there.

I DO find it interesting and tempting, by the fact that they supposedly look completely? identical except for the terminals, and that just because one says made *FOR* the Williams Furnace Co. could very well be the same Robertshaw valve. But because of doubts raised by someone who is knowledgable, like mbk3, I would at least want to ask one of the guys, like I've been able to talk to, in one of those heating departments.

This gas valve was to replace a defective gas valve that had an intermittent habit of just shutting down, and also of not starting unless one banged on it's side. That valve itself was a replacement for the valve that came with this old Dayton 35,000 btu space heater. Correct me if this is wrong, but as far as I can tell just about any millivolt space heater gas valve with that capacity and more will work. The Robertshaw valve I bought has a 70,000 btu capacity, most others that were available are much more in the 150,000 to 300,000 btu range. I wanted the Robertshaw because you can buy a LP regulator for it and I'm planning a move to an LP area.

I've been twice to the best hardware store I know of in my area, where they have the exact same Robertshaw valve on display...today I spoke with an old timer there(in their heating department) who knows these and he said the wire I'm refering to probably went to a safety in the flue (spill switch?), but he also said he thought the Robertshaw valve had a safety build inside (that esplains why this wire is plugged into a terminal on the valve) that shuts off the gas if the valve itself gets too hot. His thought was that the only difference in my valve was the male connector (instead of female connector) which in Williams furnaces would connect to the safety switch in the flue(exhaust pipe) whereas in the standard version of the valve connects to the terminal on the valve itself.

Although this seems to be the most plausible explanation, I'd like to hear from mbk3 exactly why this valve shouldn't be used for my application. I've looked at different web sites selling this valve and seen it's uses listed for floor heaters, wall heaters, fireplaces, space heaters, recreational vehicles. It mounts in any position except upside down. In my case it would be supported by a pipe that feeds the burner and it sits just outside in the back of the space heater. The previous(but not the original) valve was a Honeywell VS8194 E 1304. Robertshaw also calls this valve(in its newest version) the 710-502. They also have a valve with near identical specs called a 700-502, slightly higher btu rating (100,000) and looks to be a full size version of this one(which is a compact version designed for tight places.

To take this a little further...the correct replacement for my Honeywell valve is the Honeywell VS820A1054(335,000 btu), which is listed on the Grainger.com web site as one of the alternate replacements for the Robertshaw 700-502 which I think is the non-compact version of my Robertshaw 710-502. It never made any sense to me to put a 335,000 btu valve on a 35,000 btu space heater, but when I've asked I've always been told that it would work fine.

mbk3, what input setting are you referring to? Also, for the record, I have a Fluke CO meter which I used to check this space heater with the previous gas valve. I also have a water column device for measure gas pressure. My new Robershaw valve is supposed to be set for 3.5 w.c.

Thanks for all the comments...I hope to hear more about this.

John

That valve can be used.. I believe you should have a pro install.