Substitution of non-exact model of (buzzing) gas valve

arbalest

Four years ago I got a new Weil-McClain EG-75 installed (poorly) and without the help I received here I am sure I would be in an asylum by now.

Anyway, now the gas valve is buzzing loudly and I see from other postings that since it is working I don't have to replace it. But it is loud and I am a worrier so I want to replace it. I want to get the part (and have someone ELSE put it in) but the problem is that I am not finding an exact replacement. It is a VR8304P4348 and I am only finding VR8304Mxxxx where xxxx is anything but 4348. And there is the M vs P. But I don't see substitution guidelines anywhere so I don't know what to get or what is acceptable.

Any suggestions?

Tim McElwain

The "P" denotes a valve designed for from -40 degrees to 175 degrees of environment, It also denotes that this valve is a step opening valve. Assuming this valve is indoors and not subjected to low temps the "C " version of that VR8304 series would be acceptable as a replacement as it is also step opening.

You can however replace that valve with a VR8304P-4504 without any difficulty.

Dave0176

I’ve seen this happen and the buzzing can be annoying, sometimes just a light tap on the valve and the buzzing goes away but unfortunately on the next startup it usually returns. Most homeowners don’t like or are scared of the sound so I’ll replace it.

EBEBRATT-Ed

I would shut the power off and check and clean the wiring connections on the gas valve. Then turn the power on , start the boiler and check the voltage at the gas valve (assuming you have a test meter), Anything less that 22 volts would cause concern.

You will most likely have to change the valve but it's worth a try just for fun.

arbalest

Thanks all. The 4504 version of the part is on order. I have already "tapped" all over the thing like crazy to no avail. I will check the voltage and maybe clean some contacts. But everything looks clean inside the cabinet.

I will report back on the voltage...

arbalest

Interesting... I had the lead on mt DVM plugged in to the "mA" jack rather then the "V" jack from last time I used it. I didn't notice that but when I touched one lead to ground and the other to the blue lead to (the boiler was firing at the time) the boiler cut off. One second later the boiler restarted and now there is no buzzing.

When the boiler came back on I set up my DVM properly and both of the leads (red and blue) measured about 25VAC.

One thing I noticed as well is that the control box has two ground leads coming out of it. One is connects to the conduit box that the transformer is mounted to. The other green wire -- labeled GND (Burner) -- is just hanging there not connected to anything. It does have a spade on the loose end but it isn't connected to anything.

arbalest

In the diagram this lead is shown connected to the pilot ground. I suppose any point on the cabinet should be at the same ground. What does the community suggest? It will not reach the pilot area like this but I am willing to splice on another foot or make a new jumper.

EBEBRATT-Ed

I think the "burner ground" should best be connected to the pilot burner. It probably has nothing to do with the gas valve "buzzing" but may affect the flame sensing

BobC

It's possible that connecting that meter, while it was set for current, drew enough current to delouse a relay contact somewhere. Make sure any connection you can get to is tight and inspect any relay contacts as well.

Bob

Tim McElwain

Connect the unattached green wire to the gas valve. There may even be clips on the valve for that purpose

arbalest

Tim McElwain said:

There may even be clips on the valve for that purpose

Thanks for the suggestion. The length of the cord would imply that is where it is supposed to go. But there is a fork-like connector on the body of the valve, and my spade lug is a fork. I connected them together with an alligator clip jumper for now.

arbalest

EBEBRATT-Ed said:

I think the "burner ground" should best be connected to the pilot burner.

From the diagram that looks right too. Is it safe to assume that this wire (the insulation) can tolerate the heat where the pilot is? For now I have it connected (with a jumper) to the valve module.

arbalest

BobC said:

... drew enough current to delouse a relay contact...

No doubt something moved into place when I touched it. I like the idea of "delousing"!

The only external connections are the two 24v and the neutral between them. Then there is the fork lug right on the body of the valve module. I will check everything when I get in there again. Thanks.

unclejohn

Check to see where the ground wire that has the spade connector on it goes. It may go to the burner and the wires got switched around. Not sure if those two ground connections are separate inside the control or not. Tim knows.

arbalest

The installer/handyman I contacted has been dragging his feet so I replaced the valve myself. There isn't much to the actual work. HOWEVER, now when the thermostat calls for heat I hear the usual pre-firing sounds but it doesn't fire. That is: the damper opens, there is a hum that I assume is the igniter. Then when I expect to hear the rush of the burner starting instead I just hear a click, then silence. The igniter (if it is that) goes quiet.

I've checked my work and it all looks okay. In other installations (like the hot water heater) I've seen the installer back off the gas line drip tube to purge air from the system. I have not done that.

In any case, it might be time to call a pro. I thought I'd post here in case it is something obvious.

arbalest

I repeated the on/off cycle 4 more times while I was trying to figure out what was going on -- now the boiler fires. Maybe it was purging the air that way?

BobC

It was air in the pipe, make sure you test for gas leaks on the piping and valve.

Bob