Robert Shaw Millivolt 710-503 valve response issue

[rwh63]

i have a 1996 VC Radiance model 2600. bought it new. the original valve performed well for years, mostly on thermostat. it became non-responsive (could tap the underbody to get it to open up). there have been two or three new valves installed over the past decade or so. same issue. fine for a while, then non-response (underbody tap). dealing with it again. the rocker switch will sometimes operate it, but sometimes not. thermo will not.

so, what keeps causing these to fail? all i can think of is moisture-derived rusting out internally that is causing the valve to be sticky. hate to keep replacing them. tried to contact Shaw tech support. no answer, no call back.

 

[DAKSY]

Somewhere in the fuel line to the unit, a drip tee should be installed. Have you ever opened it to drain the sediment out?

 

[rwh63]

i have not.

 

[rwh63]

Here are some inside pics. Probably a tee outside on the line before it enters the house, but don’t see anything near the stove.

might note, this is propane.

 

[DAKSY]

Many times in the past, they weren't added to an LP line, but they should have been.
They can help to keep debris & moisture from reaching the gas valve if opened every once in a while.

 

[rwh63]

So, I’m screwed?

 

[DAKSY]

I guess so, unless you can rebuild this one.

 

[rwh63]

I could, of course, buy a new valve and have it installed. Perhaps have a tee installed as well.

 

[Fingerlakes Fireplace]

i have a 1996 VC Radiance model 2600. bought it new. the original valve performed well for years, mostly on thermostat. it became non-responsive (could tap the underbody to get it to open up). there have been two or three new valves installed over the past decade or so. same issue. fine for a while, then non-response (underbody tap). dealing with it again. the rocker switch will sometimes operate it, but sometimes not. thermo will not.

so, what keeps causing these to fail? all i can think of is moisture-derived rusting out internally that is causing the valve to be sticky. hate to keep replacing them. tried to contact Shaw tech support. no answer, no call back.

Most likely its a wiring problem.
You can spend a lot of time trying to figure out which wire it is, by doing voltage drop tests.
The easier way would be to just replace ALL the wires on the stove.
And wire your thermostat directly to the gas valve, and not through the switch.

 

[rwh63]

Most likely its a wiring problem.
You can spend a lot of time trying to figure out which wire it is, by doing voltage drop tests.
The easier way would be to just replace ALL the wires on the stove.
And wire your thermostat directly to the gas valve, and not through the switch.

the main reason i would disagree is when this has happened in the past, a new valve would then work normal with the thermo and rocker.
and, why would the valve open by tapping the underbody?

i could replace the thermopile for about $30 to see if there is enough juice being produced by it to trigger the valve response.

 

[Fingerlakes Fireplace]

the main reason i would disagree is when this has happened in the past, a new valve would then work normal with the thermo and rocker.
and, why would the valve open by tapping the underbody?

i could replace the thermopile for about $30 to see if there is enough juice being produced by it to trigger the valve response.

Or maybe you could replace the valve again. It "fixed" it the other times.
Maybe the 5th time is the charm...

 

[rwh63]

If I could do it myself, I would. However, I have to purchase the device, then arrange an install. Was trying to see if the issue could be elsewhere.

 

[Fingerlakes Fireplace]

If I could do it myself, I would. However, I have to purchase the device, then arrange an install. Was trying to see if the issue could be elsewhere.

You totally missed the sarcasm in my last reply

 

[rwh63]

so, the valve mechanism works fine when i "jump" the thermostat wires (touching red to white). but when i hook the wire to a millivolt
thermostat though, it did nothing. what does this tell us?

 

[rwh63]

You totally missed the sarcasm in my last reply

actually, i didn't.

 

[rwh63]

update: cajoled a free "warranty" replacement valve and propane regulator out of Robert Shaw. got it installed for $390(!). Stove back to working normally. Shaw says the valve should not be failing in several years, as does installer. no idea why it is.

 

[Millbilly]

update: cajoled a free "warranty" replacement valve and propane regulator out of Robert Shaw. got it installed for $390(!). Stove back to working normally. Shaw says the valve should not be failing in several years, as does installer. no idea why it is.

Did you test the thermopile?

 

[rwh63]

Did you test the thermopile?

not with an instrument, but it was holding the pilot on, and the new valve is responding fine. the thermopile was a VC replacement several years ago.