Bad Zone Valve or ?

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  #1  
Old 12-04-07, 12:11 PM
J
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Bad Zone Valve or ?

Hi, JR here (a newbie). I have a three-zone radiant heat system, controlled by three RiteTemp programmable thermostats. Two of the zones work fine, but the third zone this year doesn't. I tried resetting the thermostat, replacing the batteries, swapping out one of the other working thermostats temporarily ... all to no avail. The other zomes all heat up, but the front zone just stays at ambient temperature, no matter what I set it to. No heat from the floor, nada.

My zone valves are Honeywell V8043E models - motorized valves 24v 50/60 Hz 32amp. When one of the other valves is actuated by the thermostat, you can feel the heat in the pipes, but not with the bad one. Any ideas? Thanks.
 
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  #2  
Old 12-04-07, 02:49 PM
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V8043 Valves

These valves are very easy to test to determine if they are open or not. At the base of the cover is a lever. When the thermostat is calling for heat the lever should move easily from one side to the other. If it does not, the valve is not opening. You can also (with some resitance) move the lever to the manual open position & latch it in the notch. With the lever latched open, hot water should flow thru the valve.
 
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Old 12-05-07, 08:40 PM
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Grady gets to the point but I like to give the entire lesson, especially to a nubie. (hehehehe)

Class: "Zone valves 101": (hehehe)

1)Go turn off all the thermostats. Go 'feel' the little lever on all three zone valves. They should ALL feel tight. This is OFF.

2)Now go turn on one thermostat (to maximum)that you know works. 'Feel' the lever on the zone valve. It should feel loose. This is ON. You should also be able to feel the hummmmmmmmmm of the circulator if you put your hand on it.

3)Turn it off again. The circulator should also be off. Good so far?

4)Turn on the second thermostat that you are sure works (to maximum). Again check the lever on the zone valve to make sure it is on, it should feel loose like the first one. The circulator should be a hummmmmmmmmmmming. Everything ok? Good!

5)Turn it off again The circulator should also be off. Good so far? 2 done, one to go.

6)Turn on the THIRD thermostat that you say is NOT WORKING (to maximum). Again check the lever on the zone valve to make sure it is on, it should feel loose like the first and second ones. The circulator should be a hummmmmmmmmmmming. Everything ok?

DIAGNOSIS:
IF the lever is NOT LOOSE like the other ones then take off the thermostat (#3) and short the two wires together, usually red and white and re-check. If it works now, the lever gets loose and the circulator is hummmmmmmming, change the thermostat!
IF you still have a 'tight lever' and it has not opened then you need to see if you are getting 24VAC on the yellow wires to the zone valve. If you are not then you need to trace back to see why not, (may have a loose connection, have a separate 24VAC transformer than the other 2 zones, may have a loose wire nut under the cover of the zone valve)
If you are getting 24VAC on the yellow wires and the zone valve is not moving, even when you try to help it a bit by moving the lever, then guess what- change the zone valve!
( You can do it yourself by just changing the actuating mechanism, not the whole valve. Take off the clock motor assy. by removing the small screws. You'll figure out the rest)

Now, there is a small chance that the lever will move and that the zone valve will open, and it will feel loose, but you may not feel the hummmmmmmmming of the circulator. Well, now comes -you got it-
CLASS---------"Zone valves 102"---hehehehe
IF the lever loosens up, the valve opens, you got 24VAC on the yellows, but no circulator, then the microswitch is not being actuated. Either the microswitch is bad, or the clock motor got weak and it is not letting the rack gear travel far enough to hit the button, or the gear is stripped on a particular spot, or something is preventing the 2 RED wires from getting continuity to energize the circulator. Now you need to do a little detective work!

OOOOOPS! My coffee is getting cold! Let me know if you are ready for "Zone Valves 103"--- professor. (HEHEHE)

Good Luck! Charlie
 
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Old 12-08-07, 03:14 PM
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zone valve problem 102

Originally Posted by boilersrus View Post
Now, there is a small chance that the lever will move and that the zone valve will open, and it will feel loose, but you may not feel the hummmmmmmmming of the circulator. Well, now comes -you got it-
CLASS---------"Zone valves 102"---hehehehe
IF the lever loosens up, the valve opens, you got 24VAC on the yellows, but no circulator, then the microswitch is not being actuated. Either the microswitch is bad, or the clock motor got weak and it is not letting the rack gear travel far enough to hit the button, or the gear is stripped on a particular spot, or something is preventing the 2 RED wires from getting continuity to energize the circulator. Now you need to do a little detective work!
Hey, this is what I am currently dealing with! I have the honeywell V8043 style with the four wires. I've already done the detective work and determined that the switch is good cause when I move the "rack gear" out of the way to the open position with my screwdriver, the microswitch pops out like it is supposed to and the boiler starts up. But when that zone's thermostat wants heat, only the zone valve opens and this "rack gear" doesn't travel far enough on it's own (no boiler start-up). So it sounds like my motor might be weak based on your options( I don't see any stripped gears). that is good cause then I will only have to replace the motor and not the whole upper, right? I'm afraid though, that if I try to replace the 24v motor, springs and levers will go flying and I won't install it properly. Assuming that I will only have to replace the motor, how do I make sure I install in right? I'm thinking it might be a safer bet to just replace the whole upper.
 
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Old 12-08-07, 03:33 PM
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Majormajor

It is highly unlikely the problem is with the motor unless you can hear some unusual noises from it when it's opening. The swithes in those valves have a habit of wearing out. If you do a search within this forum for "microswitch" you should find a thread in which someone posted a link to a supplier of replacement switches.

If you hear any grinding or clicking from the valve when the motor is operating, the motor is the likely culprit.
 
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Old 12-08-07, 07:45 PM
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I think the switch is good

It will be awhile before I can work on this again but I think the switch is doing what it is supposed to do. I'll wait and see what Boilersrus has to say (awaiting zone valve class 103), but if I want to test your theory that it is in fact the switch, I'll just swap the switch from the zone that is working with the one that isn't and then I'll see if the problem then moves to the other zone. I just hate working with those tiny screws.
but first, I'll see if the zone valve motor is making noise like you mentioned. I've been working by myself and walking back and forth to the thermostats to make the zone valves open and close. Therefor I haven't actually been standing next to the valves when they operate. So I'll either have someone in the other room operate the thermostat so I can listen for "unusual noises" or figure out how to short the valve locally and safely so I can test it right there and listen. can hardly wait to report back what I find.
 
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Old 12-09-07, 03:00 PM
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zone valve is very slow to operate

so I had someone operate the thermostat while I was standing next to the zone valve. compared to the good one, the bad one opens very slowly. it sounds weak and doesn't travel far enough to rotate the rack gear to the point of activating the microswitch and start the boiler. Maybe I should swap the zone valve 24V motors between my two zones and then I'll know for sure if the problem is a bad motor?
 
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Old 12-09-07, 03:32 PM
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Swap motors

Motors are a lot easier to change than end switches. One screw & a hook 180º from the screw hold them in place. You don't have to worry about springs flying out.
 
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Old 12-09-07, 04:41 PM
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Voltage Issue on the Valve

If someone could help I would much appreciate it. Already done a lot of the troubleshooting but not complete yet. Honeywell valves (8043e). 3 zone system. One valve not working. Not the thermostat, one transformer (not that), valve not sticking (can open manually). Here's the twist for me which may mean something to someone of the board. The valve not working is the only of the 3 with external terminals ( i assume that is because it is the end switch). Power coming into the valve (on one side of the terminal) is about 26-27 volts (so that seems fine) but voltage from the terminal side going to the thermostat is only about 22 volts. I assume this is part of the reason the valve does not respond when the thermostat initiates a call for heat. I am a novice with heating systems so my assumption may be way off. Any help is appreciated.
 
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Old 12-10-07, 04:36 AM
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the motor is bad.... that's exactly what happens.. motor is too weak to pull the lever over to energize the end switch. the motor will be real hot to the touch also

22 volts is just normal voltage drop, so dont worry if the thermostat only sees that voltage it will still work
 
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