Zone valve question

Rkh

Member
This zone valve goes to my attached garage & thermostat controls temperature. When
it gets cold outside, it stops working in the auto mode, so have to turn to manual
so get heat from the house zone. Sometimes it goes back to auto on its own. When I
say cold outside, its when wind chill is low or below 10degrees. I've replaced zone
assembly, but not the copper body the unit fits in. Any ideas why zone valve
doesn't open when cold & could it be the zone copper body that holds unit.
cvphoto73190.jpg
 
When the zone valve operates it either turns or pushes down on a valve allowing water flow. Check to make sure that valve moves easily, maybe a drop or two of 3-1 oil will help
 
I've replaced Powerhead Conversion Kit & motor unit(not the copper housing) & I get the same results-when it gets super cold it stops working.
 


Are you absolutely sure that it opens when it is only moderately cold? or is it only that you don't notice it unless it is very cold.
 


Rkh, I can't tell what you mean by "I've replaced zone
assembly, but not the copper body the unit fits in" The whole assembly that you are working on is a zone valve. It consists of two parts: the operator head, which is the part enclosed in the aluminum housing, and then the body which is the bronze casting and the working parts. If you have not yet replaced the moving seal inside the bronze body, go ahead and try that. You won't have any trouble with it. The biggest thing to it is isolating it from water pressure.
 
It seems to me that if it only malfunctions in freezing temperatures, something must be freezing. I wonder if a blockage upstream of the valve can prevent it from opening? Maybe when the pipe freezes it puts enough pressure on the valve to cause it to jamb?

Our house has one zone that can freeze when it gets down around zero because of a pipe that's routed close to an exterior wall. I'm always careful to set that zone warmer than the others so it doesn't freeze.
 
I've replaced this part
https://www.supplyhouse.com/Honeywell-Home-802360JA-Replacement-Motor-for-V8043-
Zone-Valves
 
I've also replaced this part
https://www.supplyhouse.com/Honeywell-Home-40003918-006-2-Way-Powerhead-Conversion-Kit-Water
 
(quoted from post at 12:27:00 01/28/21)

The yellow wires supply 24 VAC to the little "clock motor" in the "power head" when it needs to open the valve.

Next time it mucks up check the voltage between those two wires and let us know what you find.
 
Wore out: can you explain your response(im not that great at electrician)

Next time it mucks up check the voltage between those two wires and let us know
what you find.
 
Your picture isn't clear, but it appears that the manual control lever is not hooked on the catch. That tells me the control head motor must be working, because the lever would return back to the valve-closed position without the motor holding it in the valve-open position. So, for some reason the motor force is insufficient to open the valve but sufficient to hold it open. Again, I think something is freezing in that zone and it's causing the zone valve to act up.
 
If it’s a Honeywell like mine ,the little micro switch has failed. Good luck trying to find one. I always just bought the guts and swapped it , the other thing is the motor if switch goes bad then it’s overheating the motor and burns it up , test motor , motor comes with the repair . You don’t neeed the entire valve.
 
I put on manual when zone valve stops working. That allows water to that zone & the manual mode works as suppose to.
 
> I put on manual when zone valve stops working. That allows water to that zone & the manual mode works as suppose to.

Yes, I realize that. But are you hooking the lever so it doesn't return, or does it stay put on its own? If you don't hook it and it stays on, then the motor is holding it open. Meaning the valve is getting power and the motor is exerting torque on the valve.

Are you sure water circulates through the zone when you open the valve? Or are you just assuming it is because the valve is open?
 
My 1 zone valve does this every year, when I start my boiler. I have to run the zone valve on and off several times to free it up for some reason. The other zone valve works fine. I have had the same problem when I forget to replace the batteries in the thermostats every year.
 
> I have to hook up manually in the notch

OK, it was hard to tell from your pic.

Just to be clear, there are four wires going to the control head. The two yellow wires provide ~24Vac from the thermostat to activate the control head motor. The two red switches go to the microswitch in the control head to turn on the boiler and circulation pump when the valve is open. Since the switches in all the zone valves are connected in parallel, if one switch is bad that zone will still circulate if another zone is operating. If you want to test an individual switch, you need to disconnect that switch and check its resistance while manually opening the valve. I assume you already know all that, but I thought I'd explain it just to be sure.
 
(quoted from post at 04:56:03 01/30/21) Wore out: can you explain your response(im not that great at electrician)

Next time it mucks up check the voltage between those two wires and let us know
what you find.

The valve is opened by a little "clock motor" that is "impedance protected", it "stalls" once the valve is "open" and doesn't overheat even though there is constant power to it as long as there is a "call for heat" for that zone.

Once the thermostat is satisfied it cuts off the 24 VAC power to the "clock motor" and the valve is closed by spring action.

To open the valve reliably the thermostat circuit has to supply 24 VAC (nominal) to the "clock motor", that's what the two yellow wires do.

So when it's not working, take a meter capable of reading AC voltage and check across the two yellow leads.

If voltage is significantly less than 24 VAC or absent altogether that would indicate a problem in the thermostat or the associated 24 VAC circuit.

If that checks out (since you state you've already replaced the "powerhead") the next thing to do is replace the cover/valve ball unit.

https://www.zoro.com/honeywell-home...eam-40003918-008/i/G7447896/?recommended=true

SogIqOY.jpg


Obviously, care is required to replace that, turn off "boiler" and allow the system to cool to a "non-scald" temperature "just in case, then hopefully there's valves to isolate that circuit for repairs.
 
(quoted from post at 13:03:38 01/30/21)

Wore out, he told us that he has already replaced the inner ball part/cover plate.

Yes, I see that, he did not mention that in the initial post, and I missed the posts in the middle of the thread about that.

It sure would be interesting to know what the voltage is to the motor when it won't open.

One other thing I thought of (and I don't know why this would affect operation only when cold) is to verify for 100% sure that the valve is installed in the correct flow direction, there is an arrow on the brass body that shows required flow direction. When installed correctly the rubber ball is forced "closed" against the INLET port in the brass body by the force of a tension spring in the powerhead.

So to "open", the little "clock motor" has to overcome only spring tension, if backwards it would have to overcome pressure from the circulating pump forcing it against it's seat IF the pump is already running doe to a "call for heat" to another zone valve.
 

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