Zone Valve problem in a condo


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Old 11-28-10, 09:52 PM
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Question Zone Valve problem in a condo

I have a problem with too much heat in my condo. I was told that my zone control valve needs replacement.

http://i1196.photobucket.com/albums/...mad/zonev3.jpg
http://i1196.photobucket.com/albums/...mad/zonev2.jpg
http://i1196.photobucket.com/albums/...mad/zonev1.jpg

No idea what the current zone valve is, but I am thinking about replacing it with Honeywell (my thermostat is Honeywell as well).

Questions:
Any guesses as to if it's a always on or always closed valve? I plan to check the voltage with a meter, but wanted to see if the attached photos make sense to anyone?

Though no professional, I am fairly comfortable connecting copper pipes and stuff. Is it as simple as turning off hot water supply, cutting off the old zone valve, soldering the new one in, and power it up?

Any tips would be greatly appreciated. Thanks in advance!
 
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Old 11-29-10, 07:50 PM
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Any suggestions?

Also, I found out today that thermostat has 26 volts when it asks for heat and 12 volts AC when it doesn't. I trust it means I have a normally closed valve. True?
 
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Old 11-29-10, 08:34 PM
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Who diagnosed the problem as being the zone valve?

Most zone valves are normally closed, but that doesn't mean yours are, and the voltage readings that you give for your thermostat doesn't really make sense. Are there TWO wires on the thermostat?

I have no idea about those zone valves... never seen them before.
They look more like some kinda mousetrap to me...

They look ancient, how old is the building?
 
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Old 11-30-10, 07:51 AM
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The building management inspected all zone valves in each unit and I was told by my tenant that said my condo needed a zone valve.

Yes, there are two wires coming from the thermostat. That is actually one of my questions ... There are two wires from the thermostat, but the Honeywell valve has four (two yellow, two red). How would I connect?

The building is about 30 years old.
 
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Old 11-30-10, 04:10 PM
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Without knowing what those are, and being there to inspect the wiring, I can't really advise how a Honeywell will replace them.

What I'm thinking you have there is a type of valve that requires POWER to OPEN, AND POWER to CLOSE. The Honey valves are POWER OPEN and a SPRING RETURN TO CLOSE.

There is probably more wiring somewhere... in other words, those two wires that come out of the wall, the red and the white, are almost definitely NOT the same two wires that go to the thermostat.
 
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Old 11-30-10, 04:36 PM
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Originally Posted by scarlethawk View Post
The building management inspected all zone valves in each unit and I was told by my tenant that said my condo needed a zone valve.

Yes, there are two wires coming from the thermostat. That is actually one of my questions ... There are two wires from the thermostat, but the Honeywell valve has four (two yellow, two red). How would I connect?

The building is about 30 years old.
I would say that 2 of the wires power the valve motor (maybe thermal) and 2 are an endswitch that call the boiler.

Not sure how simple it will be to swap that valve. You need to make sure the close off pressures are the same for the old and new.

Can you isolate the unit (suite) ?
How tall is the building ?
 
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Old 11-30-10, 04:57 PM
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From what I can see in the pics, it looks like only two wires are coming into the valve from the system. The BLUE and ORANGE look like they are going to the 'motor?' ... the green thing on the end... which may be a 'heat motor' (probably is).

It also appears that the ORANGE wire is just twisted loosely around that terminal on the left side... probably not making good connection.

Scarlet, can you confirm how many wires are coming to this valve from the system, and can you get a better picture showing how the wires are connected to the valve?
 
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Old 11-30-10, 05:05 PM
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If this valve only has two wires going to it, and the Honeywell valve will meet the close off spec that TO is talking about, AND, TO also asked if you could ISOLATE the suite...

What he means is that unless you can close some valves to ISOLATE that section of pipe from the system, you will have to DRAIN THE WHOLE SYSTEM, which is NOT an easy job in a small building, let alone a large one... well, the draining is pretty easy, but the REFILLING AND PURGING OF THE AIR when you are done is tricky... harder than it sounds...

BUT, back to the two wires... IF there are only two wires, you can simply ignore the two RED wires. They will not be used. Honeywell DOES make models that do NOT have the two red wires, but they are harder to find and sometimes cost more because they are not typically 'stocked'.

The biggest problem in a situation such as your is going to be getting the pipes drained so that they can be soldered. One single drop of water is all it takes to create a leaky solder joint.
 
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Old 11-30-10, 05:07 PM
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Does the building have a single boiler system that feeds a number of condo units?
 
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Old 11-30-10, 11:30 PM
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It's a two story building with 10 or so units on each floor, the boiler is in the basement and supplies hot water to all units. In each unit there is a thermostat and baseboards. The baseboard closest to thermostat has (what I think is) the zone control valve.

Next to the zone control valve, is a faucet kind of thing, something like ...
http://www.allproducts.com/manufactu...m/product3.jpg

which I believe shuts off hot water to the unit, so the zone valve can be replaced.

I appreciate any input. Thanks!
 
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Old 12-01-10, 03:55 PM
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That valve you pictured IS a stop valve, but it is only ONE of TWO that you would need.

Remember that heating systems are CLOSED loops, so even if you close ONE side, the water will still come pouring out the other side.

In a building such as yours it is very likely that the pumps may always be running, and the valve opens and closes as needed to provide heat. You can't shut down the boiler to do the changeout, so you MUST be able to close BOTH sides of the heating pipe in order to change a valve.
 
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Old 12-01-10, 04:00 PM
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Scarlet, can you confirm how many wires are coming to this valve from the system, and can you get a better picture showing how the wires are connected to the valve?
Is another pic possible? Are there two wires or not?
 
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Old 12-01-10, 04:24 PM
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Yeah, no end switch.

So something must power the Tstat.

I doubt the system pressure would require much elobarte in the way of zones valves. Any general purpose zone valve would work.
Erie, Invensys. Bellimo, Honeywell. All pretty much the same.

Unless there is a drain point somewhere on the system, your gonna have fun trying to get the water out without a mess.
 
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Old 12-01-10, 05:17 PM
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Unless there is a drain point somewhere on the system, your gonna have fun trying to get the water out without a mess.
Ain't that the truth!

And again, unless you get those pipes DRY, you are gonna have a heckuva time getting it properly soldered... which brings up another point... given the fact of the close quarters that valve is in, and the combustible materials so close to it, my advice is to get a pro in to tackle that. Doesn't look like a DIY project to me.
 
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Old 12-01-10, 09:34 PM
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Yeah, there are two wires in the cable from the wall, the red one and the white one. Other wires are cross-connects within the zone valve.
 
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Old 12-01-10, 09:37 PM
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Originally Posted by NJ Trooper View Post
Ain't that the truth!

And again, unless you get those pipes DRY, you are gonna have a heckuva time getting it properly soldered... which brings up another point... given the fact of the close quarters that valve is in, and the combustible materials so close to it, my advice is to get a pro in to tackle that. Doesn't look like a DIY project to me.
Yeah, I look for another valve to see if I can close hot water in pipes. I will check and report back.
 
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Old 12-02-10, 08:15 PM
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I checked, in addition to a shut-off valve by the zone valve, there is another shut off valve in the other room, where the pipes go down to the basement, I assume. Right next to that other shut-off valve, there is a faucet type of thing, I trust to flush air or water out.

So, if I understand it right, I can shut off both sides of the hot water pipe, cut the pipe replace zone valve, and open the shut off valve. Am I right? What are other considerations?
 
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Old 12-02-10, 08:27 PM
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I'm still VERY concerned about you getting in there with a torch. I do NOT want to hear that you've burned down the building!

I'm also wondering if it's even LEGAL for a non-licensed person to do plumbing and heating in a MULTI-FAMILY BUILDING in your city. You might want to check before you get in trouble.

You still should measure the voltage on those two wires. IF you see 24VAC on them when the thermostat is calling for heat, AND when you turn the thermostat down, that voltage goes to ZERO, then you know that the valve is a normally closed 24V valve.

If those two shut-off valves are positioned such that you can isolate and drain that section of pipe, yes, that is what you would need to do.

When you are finished, you want to get the air out of the pipe before you turn the valve on that goes back downstairs. You can do this by opening up the supply side valve first, turn the thermostat up to call for heat, open the drain valve until you have a steady stream of water with no air, close the drain valve and only then open the return valve.

You won't be able to drain the pipe at floor level if you have to run a hose UP to a sink to drain though. I might recommend finding a way to hook a wet/dry shop vac up to that drain fitting to suck the water out. Hook up the vac, turn it on, make a cut or drill a hole in a section of the pipe you will be removing to suck air and let the vac suck the water out.
 
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Old 12-02-10, 08:41 PM
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Yes trooper is correct you should be careful. Here in NJ a local plumber will install that for about $373 with service call and a 1 yr warranty parts and labor. If you get caught doing this late at night and have trouble a plumber will charge $150 or more just to walk through the door. Plus what floor are you on? Imagine flooding the downstairs apt. At least the company would be resonsible and not you if something bad happens.

Mike NJ
 
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Old 12-02-10, 09:16 PM
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Originally Posted by NJ Trooper View Post
....You still should measure the voltage on those two wires. IF you see 24VAC on them when the thermostat is calling for heat, AND when you turn the thermostat down, that voltage goes to ZERO, then you know that the valve is a normally closed 24V valve.
...
This I am still iffy about ... as mentioned earlier, the voltage is 26 VAC when heat is called and around 8 VAC when it's not. Is that close enough to 24 VAC and 0VAC? Is it a thermostat issue or wherever the voltage is coming from (a central location that supplies the voltage to all units)?
 
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Old 12-03-10, 07:18 AM
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If you measure 26 volts when you are looking for 24, it's fine. There is an acceptable range of voltage that appliances operate on. When you are looking for 0 volts, you are making sure there is no electricity being supplied. So if you find any voltage, then that means there is electricity flowing.
 
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Old 12-03-10, 08:04 AM
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Originally Posted by drooplug View Post
If you measure 26 volts when you are looking for 24, it's fine. There is an acceptable range of voltage that appliances operate on. When you are looking for 0 volts, you are making sure there is no electricity being supplied. So if you find any voltage, then that means there is electricity flowing.
Is it a thermostat issue?
 
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Old 12-03-10, 05:21 PM
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It's very difficult to tell what issue, if any, exists from the limited information that we have. There does appear to be some 'leakage current' somewhere in the system. Probably not a thermostat issue... without knowing how that is all wired it's impossible to know for certain. Maybe that residual 8 volts is enough to keep that valve hanging open and causing the overheat that you are complaining about?

I think before I went to the time and expense of changing that valve it would be wise to investigate why and how you are seeing 8 volts when there should be zero.

You may in fact need a new valve but I think this should be looked into FIRST.
 
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Old 12-03-10, 09:59 PM
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I'm more inclined to think the 8 volts is a "phantom" reading.
 
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Old 12-03-10, 10:12 PM
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I thought that too, but given that it's a 24V circuit that 8 V was kinda high for a phantom. That, and the fact that the original post said it was too hot in the condo, which made me wonder ... even so, before going to all that work to replace a valve, it should be checked.
 
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Old 12-03-10, 10:20 PM
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Remember that the presence of phantom voltage has more to do with the input impedance of the voltmeter than it does the voltage of the circuit.
 
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Old 12-04-10, 02:23 PM
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Originally Posted by Furd View Post
I'm more inclined to think the 8 volts is a "phantom" reading.
What do you mean by phantom? input impedance of the voltmeter?
 
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Old 12-04-10, 03:17 PM
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I assume that you were using a digital voltmeter. The "input impedance" is a figure denoting how much of a "load" the voltmeter places in the circuit, a load being a consumer of electricity such as a lamp. Digital meters have a very high input impedance which means they put very little load on a circuit, the result is that digital meters are VERY sensitive to small voltages. Conversely, simple analog meters have a fairly low input impedance and do load a circuit far more than does a digital meter.

The end effect is that a digital meter will often show a voltage even when the test leads are not connected to anything. When they are connected to a circuit that should be "dead" they will often show a voltage that has no current (amperage) behind it. If you used an analog voltmeter on the same circuit it would read zero. Since there is no current to "force" the voltage, i.e. no actual current "flow" no work can be accomplished by the apparent voltage and it is often called a phantom voltage.

Here is a paper that explains the phenomenon in depth. (pdf)

http://www.nema.org/stds/eng-bulletins/upload/Bulletin-88.pdf
 
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Old 12-04-10, 03:28 PM
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The more I look at that zone valve the more I think it is a "heat motor" activated valve. It is possible that the heat motor (really a big resistor that heats a wax pellet that expands and pushes against the spring) has burnt out or possibly the valve seat has something that is keeping the disc from closing. The zone valves that I am familiar with that used heat motors were normally open valves with the spring holding them closed.

You might try disconnecting the wires and then taking a resistance measurement across the motor terminals (the green thing on the left end with the orange and blue wires) and see what the resistance is. An open reading (infinite resistance) shows that the heat motor is dead.

You can also try to clean out the dust and dirt around the unit and then see if you can push down the center cap under the "bridge" between the motor and spring. You might be able to wedge a screwdriver under there and that should close the valve.

Looking at the first picture (top view) I think I see a screw on the left side, just right of the heat motor, that should have a corresponding screw on the back side. Removal of those screws should allow the "superstructure" to swing to the right (unless there are also screws on the right side I can't see) and lift off. Then the stem of the valve can be manually pushed down and see if that stops the heat.
 
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Old 12-04-10, 04:42 PM
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Thanks for the suggestions!

I am using a digital meter (an older bulky Fluke) I also tried disconnecting the wires that go to the zone valve to take voltage measurements thiking maybe the valve is messing them up but they were same (26v and 8v).

I was thinking I had the valve narrowed down to normally closed valve. You are thinking maybe it's normally open. Are you sure?
 
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Old 12-04-10, 05:16 PM
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I dont know but if that is your only zone you must be cold in IL. Just say'in.
 
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Old 12-06-10, 05:06 PM
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Maybe, since you feel its a valve issue, go buy a replacement and wire it to the stat with out doing any soldering work.
Turn the heat up, if the valve opens then turn the heat down, if the valves closes then your golden. change the vlave and you should be warm, and hopefully not wet.
If when you turn the heat up the valve is closed and when the heat is off the valve is open then go get a normally closed valve.
 
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Old 01-10-11, 11:59 AM
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Thanks all! Specially NJ Trooper!

I bit the bullet and changed the valve with Honeywell. The biggest challenge was to get the pipes to be completely dry (there were drops dripping with shutoff valve) but got it replaced and is working like a charm.

Thanks all, you have been a great help!
 
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Old 01-10-11, 05:05 PM
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Thanks Scarlet for letting us know, and you're welcome!
 
 

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