Leaking gas valve- VAL06376

[ruud-man]

I am working on a Trane 80+ 2 stage. The original complaint was the gas company red tagged it because it was bleeding through on the off cycle.

The inlet pressure is 7" and we have put three valves (VAL06376-W/R valve) on this with the same results.

It doesn't matter if there is power to the furnace or gas valve, it still leaks.

Any ideas.

Thanks

[doc havoc]

ruud, is the gas actually leaking through or is the gas company picking up the residue the gas is leaving in the manifold? I've struggled with the gas company around here on this issue. Factory field tech even got involved on this to back me up. The gas will leave a residue that a leak detector will pick up. It's funny though, because Trane had an issue with gas valves a while back where they weren't closing completely. I don't remember the model, but it was before the 2 stage came out. My two cents

[ruud-man]

Doc,

Thanks for the info. The tech tells me that it is a steady leak. The residual gas is the first thing we jumped on.

I've got a feeling there is a lesson to be learned here somewhere.

[simpleman]

Ruudman,when you say no power to the unit..do you mean the
stat not calling or the burner switch is turn completely off?

[ruud-man]

Gas still leaks through if the stat is not calling or the 110V is turned off.

We haven't tried the manual valve. I'll ask about that.

Thanks

[dave_slo]

3 valves, all of them leaking the same... Something's not right here. Do you have a way to test these valves in another set up? Like just hooking the valve to a gas line at the shop?

Could be crud getting in the valve if the plumbing isn't right. But 3 valves??? would have to have a lot of loose stuff in the pipes I would think.

Start with a known, good valve, tested by you, blow out the lines before installing, and make sure pipe run has a drip leg at the furnace. Install a fitting so you can monitor pressure at the valve, both while its running and when you shut down. Should remain within specs. If outside regulator isn't working properly, creating pressure surges, you could damage the valve in theory, haven't seen it happen though...

If you still pick up a leak after this, it HAS to be coming from somewhere else.

[mark beiser]

You sure the tech isn't assuming there is a leak because hit electronic detector goes off when he put the probe against an orifice?
My Tif8800 will pick up a "leak" from a used manifold that has the gas valve removed and the manifold blown out with CO2!

I find it highly suspicious that 3 valves have leaked...

[mike3]

Did you flash the orifices or run a soap bubble across. I tend to agree with Mark. We had tech who would find a bypassing valve on about every gas leak call. Had to show him when to not use his detector.

[ruud-man]

Thanks for all your input. I agree 3 valves in a row are as about likely as Giacomo winning the KY Derby.

The tech actually pulled the manifold tap and determained the presence of gas by a method that I hope he never uses again. The gas supply was small but steady.

I'll let you know what we find.

Thanks again.

[gje1]

If you have multiple orfices, plug all but one and connect your manometer to the other and see if you get a constant pressure increase. I don't know where your at but if thier were copper gas lines or copper gas connectors used at one time, they'll come back to haunt you with all the deposits it leaves in the lines.

[docholiday]

I would test the lines with the manual gas valve closed and capped to verify the leak is indeed inside the gas cock and not somewhere in the piping. Then I would reinstall the local piping ane pressureize between the gas valve and gas cock and check for leaks (connect to drip leg maybe). The gas company should not test the lines exposed to the gas valve with more than 1/2 psig. If they do, then they can keep buying valves.

[HVAC Pro]

The gas company around here generally performs a "drop test" where the meter is removed, a plug fitted with a barbed fitting is connected to the meter bar and they pressure test the entire system with a water column pressure test. This is done with all the gas cocks open and the equipment valves in the 'on' position. If pressure is lost, the gas cock to each appliance is closed one at a time until the problem appliance is determined. I actually have a setup to do this with but have yet to wrestle with dropping a meter.

[ruud-man]

Thanks for all the input. The gas company tested the furnace again and measured about 200ppm (at the orifices) just after the valve was de-energized. The reading slowly increased to around 600ppm and stayed steady during almost 15 minutes of testing.

The gas company passed it. So I guess the story is over as far as the customer is conerned.

Thanks again...