Honeywell Zones Stuck Open

watercress

Zones are Honeywell 40003916-026 For V8043E.

Two zones are okay, two zones are stuck open.
Thermostats where replaced recently on those zones from mercury type switch to honeywell mechanical dial type. But problems did not start right after install, seemed to work fine for a few weeks. Prior to this about a month and a half ago, there was a lot of soldering done on one of those zones as it had around 7 burst pipes. And a year prior the other now stuck open valve had two burst pipes. And it was a DIY solder job meaning possibly used too much solder. So could it be stuck open because of the solder? Anyways just trying to figure this one out as now as it's like 80 - 90 degrees in here. How do I test what information the zones are receiving from thermostats? Transformer was also replaced about 3 years ago so hoping that's not the issue.

EBEBRATT-Ed

You need a volt meter to test for 24 volts at the valve.

Other than that you can remove the thermostat from the wall and disconnect the wires from R & W (I am assuming no air conditioning on this stat)

Touch the two wire the valve should drive open. Take them apart and it springs shut.

And yes, too much solder or debris in the pipe could make the valve stick open.

You would have to remove the valve to clean or reinstall a new one

watercress

I took the cover off one of the faulty zones. I attached a picture. Where do I test for the 24 volts at?

Side note, something kinda weird here... when I lean up against the blue tank, even ever so lightly, actually I can even just press it with my hand and it doesn't feel like it moves... but when ever that happens there is a buzzing sound and I can see some electric short, possible on the copper itself... I attached a pic of behind the tank where I hear the sound and see electricity.




By the way removing the thermostat and directly contacting wires doesn't do anything. The issue is the zone is stuck open so not sure what good it is touching those wires unless the problem was zone not opening?

watercress

Hey back with an update on the electrical shorting thing. I found where the short takes place, its some thing behind the water tank... and it looks to be by where the boiler is plugged in for electricity.
Here is a video of the electrical short itself (25seconds is where you can see the spark):
https://photos.app.goo.gl/RNWRou8W7FhGiYjh7

Also I wanted to clarify about what I meant by "replaced transformer", it wasnt the thing behind this water tank if thats what that is... it was something inside the boiler, the old one looks like this:

watercress

Here is a close up pic of where that short is happening when I press the tank slightly towards the wall. Appears to be a transformer, possibly for converting the wattage down to 24 volts for controlling the thermostats?


Not sure if thats related, and if the short is just do to it being so close to the tank and the slight push causes it to jump.

watercress

Another angle of where the shorting happens with the tank. Not sure if it was intentional to have the leads on the transformer there practically touching the tank.

bburd

Regarding the short circuit:  no, those terminals should not touch the metal tank. The transformer may have been burned out by the excess current. Other low voltage electrical components may have been affected as well.

Turn off the power and insulate those terminals. Several layers of electrical tape will do if you have nothing better. Then turn it back on and see if things operate normally. You may have to do some troubleshooting to see how much mischief the short circuit caused.

watercress

Roger that. Working on insulating them now. Back to the zone valve issue, the bad zone is clearly not closing, it is stuck open. Not sure if that is controlled via electric or if it should be closing now that power is off.

Bad zone, you can see the spring is stretched open:


Compared to good zone recently replaced, the spring is not stretched, and the zone is shut:


Do the zones close themselves when there is no power? Wondering if this means the zone valve or head is bad because it is stuck open... or if perhaps it can still just be an electrical issue..

mattmia2

The spring should close the valve. Check for 24 vac on the yellow wires. There should be none when the zone is off. If you have 24vac then you have some sort of electrical problem. If there is not power then the valve is stuck for some reason. You can take the power head off with a couple screws on the base plate and see if the lever is free to move and see if the mechanism in the power head moves with applying and removing 24vac.

watercress

I got the transformer terminals covered in electrical tape. And I wedged a thin piece of wood inbetween for extra measure ( not sure if the wood idea is good considering it might put extra pressure on transformer?):

watercress

I got the power head off. Even with it off the spring was still stuck in open position. I pried around a bit with a flat head and got it to somewhat function ( see video ):
https://photos.app.goo.gl/Lg4eeDrECFujfxgN7 (around 10secs)

Seems pretty janky but atleast its moving now... Its almost like the thing was seized up on itself and by prying with the flat head it unseized it a bit. Granted I assume a new one would be smooth opening and closing...

watercress

Alrighty when putting the power heads back on and starting up the system, they do not function. They open up, but they don't close. Should I just replace the power heads assuming they are bad, or keep diagnosing something electrical? The other two zones work as they should. They also have somewhat new powerhead and guts replaced within the last couple years... but the ones that are bad, those are so old the powerheads are still made in Canada (looks like newer ones are from hungary).

And should I rule out solder being the cause? Or should I go into the zone valve itself to make sure its cleaned out. I flushed the system and didn't see anything come out other than a little dirt.

EBEBRATT-Ed

If they will not spring closed it could be the power head or it could be something in the valve body.

See the attached. Take the powerhead off and maybe you can tell if it works when not attached to the valve body. Then you can wiggle the valve stem and see if it moves freely. Put it back in the same spot before reattaching the powerhead.

I would also get that transformer and relay out of that location and mount it on a new junction box. Then run new wires between the boxes and put a blank cover on the old junction box.

mattmia2

When you were testing the powerhead removed, did you disconnect one of the yellow wires or at least test to make sure there was no voltage there? If they don't close with the wires disconnected and the powerhead removed and it is a power open spring close version of the powerhead then the powerhead is bad. Perhaps some light grease could loosen things up.

There is a power open power close version of the powerhead, does your powerhead have 6 wires instead of 4?

watercress

Powerhead has 4 wires. I ended up swapping out the powerheads on both the bad zones and things are now working again. I didn't have to do the guts as I was able to freely turn the valve with my hand.

So after replacing the powerheads, they open and close once again. I cut the old powerheads out, and then spiced the new ones into the wire left over.... so the rat nest has grown lol. But I think the problem looks resolved.

As a side note, the thermostat wires in my wall are red, white, and blue.... my thermostats have plugs for red, white, and yellow.... so I'm putting the blue wire into the yellow socket since its third wire left over... I never thought much of it but guy at parts store said I only need red and white to function the boiler and that what the blue wire for is a mystery.

mattmia2

what model thermostat is it? where does the blue go at the boiler?

watercress

I took some pictures of the thermostat and posted to this other thread:
https://forum.heatinghelp.com/discussion/194006/honeywell-mechanical-thermostat-calibration/p1#Comment_1768587

The wires I see coming from the wall that go to boiler seem to go only to the zones, and then one branches off to the boiler, and appears to connect to the control board. Its such a rats nest of wire and also covered in dust by the floor where I can't see (is where it comes in)... but I can see the wires seem to go just to zones and control board.

The whole shabang:

Wire going from zones to control board:

Control board:

mattmia2

y is for the fan on that t-stat. who knows where it goes in your system. this isn't a hydroair system with a blower over a coil is it?

there were some very old honeywell t-stats that used 3 wires for various things but this isn't one of them.

SuperTech

Your zone valve is likely getting stuck. It's common with Honeywell zone valves. If you remove the power head you should be able to move the shaft back and forth easily with your thumb and forefinger.  If you have any resistance or if it doesn't move at all then you need to drain the zone and remove the four little 5/16" bolts attaching the valve mechanism to the body. 

watercress

@SuperTech - Indeed replacing the powerheads solved the issue.

@mattmia2 - The system is just a basic baseboard heater system... one boiler, one indirect water heater tank... and thats it... no blowers... Perhaps the blue wire is just left over from running the wires and it goes to nothing at all. Is there a way to check it with a multimeter for continuity? The previous mercury switch thermostats also had all three wires hooked up.

mattmia2

Where is that particular cable at the zone valves, is the blue wire connected there? It could have been used to power a thermostat with a timer of one sort or another. They also might just have had 3 wire cable when they ran the wire for the t-stat.

watercress

The wires seem to be brown with 4 wires inside.... red white blue and green.
The red and white wires are connected to the two yellow wires from zone heads...
The blue and green wires are connected to the two red wires on the zone heads.
The blue and green wires then go to the boiler.
At the wall there is only red white and blue.