zone control valve

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wyreman

wyreman

Senior Member
Location
SF CA USA
Occupation
electrical contractor
hydroponics control where the two trades meet, at least on the job =)

hey, do zone valves, the actual brass valves - do those valves ever stop functioning?
do they even let water thru when they are supposed to be closed?

I have one valve in the "hand" OFF position [closed] and the pipe [97^] and the room [74^]still get to full temperature,

history
I have 3 zone taco control ZVC403
original reported trouble was that zone1 would be hot esp when zone2 called.

probably a photo album is worth a thousand words
https://photos.app.goo.gl/sK8yZVb58mAiPTWj9


Any experience with the Erie Valves and Actuators would be appreciated
 
G

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
190124-1341 EST

wyreman:

I am not in the business and have no experience. But with your troubleshooting experience you should be able to attack the problem.

All of the following I think you know. But I am outlining a possible procedure. Of the following experiments what have you run, and what were the results?


Some assumptions:

A zone consists of radiators of some sort, pipes, and a valve. The pipes and radiators might be in some parallel connection, but unlikely, I would expect a serial connection. There should be one and only one valve per zone, and no cross connection between zones.

When valve is open, energized or stuck open, the pipe temperature just before and just after the valve should be very close to the same value.

When the valve is closed or mostly closed, there will be a difference in pipe temperature near the boiler, and after the valve.

A valve may or may not completely turn off. There are ways to find out.

You are allowed to do whatever you want on the electrical side.

You have a digital IR thermometer.



A possible procedure:

Pick a zone that has a problem. Measure pipe temperature near the boiler for a reference. Measure a pipe temperature in the problem zone, not right at the valve. Measure pipe temperature on output side (zone side) of zone valve.

Repetitively open and close one wire to the zone valve. You should hear it change state. Obviously power to the valve has to be present to do this. Might need to raise thermostat for this zone.

If the valve appears to work mechanically by clicking, then monitor the pipe temperature on the output side of the valve. If the valve is closing when de-energized, then the pipe temperature on the output side of the valve should drop some or a lot with the valve apparently closed. So should the room cool. If there is an off fluid bypass in the valve, then when off the temperature on the output pipe won't drop as much as if the valve was fully closed. There is probably a substantial time constant to this temperature change.

If these tests show the valve to be functioning, and the systems has been piped correctly, meaning that by manually removing power to the valve that the room cools, then it would seem that the problem is electrical.

Then monitor the electrical signal to the valve at the valve. Does this signal do what it is supposed to do?

.
 
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