System 2000 issue--one zone always open

stlblufan

Hi, I have a system 2000 that has just started having an issue with one zone (on t3) wherein the thermostat is set at 50 but the zone remains open/heating continuously (and the thermostat is reading 75). What can I do to figure out what is causing this? I took the thermostat off the wall and nothing changed. I removed the wire to T3 and the output light remained on, heating continued. Any ideas/suggestions welcome! Thank you.

hot_rod

Try removing the wires at the zone valve itself. If it is a spring return type valve, you should hear is wind close.
Honeywell, Erie, Caleffi are examples of spring return valves.

A pic of the valve could help troubleshoot

109A_5

Hello @stlblufan,
Which manager do you have ? There may be some diagnostics for it.

https://energykinetics.com/control-diagnostics/

Roger

Perfect diagnostic suggestions, @hot_rod and @109A_5 . @stlblufan , let us know what you find. 

If the zone valve is bypassing without the wires connected, then the zone valve will likely need to be replaced.
If the T3 output is damaged and you have an open fourth zone, you can move the zone 3 thermostat and zone valve wires from T3 and Z3 to their respective connections on T4 and Z4. 
Roger

stlblufan

Thank you all. I have the Digital Energy Manager. Pictures of the manager and the zone valve attached. FWIW I tried disconnecting both T3 and Z3 and that resulted in just the Power light being on when I turned the system back on. I think that's what is supposed to happen but I don't know what that means in terms of what's at fault.

109A_5

Hello @stlblufan,

stlblufan

This is with T3 removed. The problem here is that T2 is calling but not showing up. 

EDIT: actually T2 went into Eco mode when I turned off the system so it wasn’t calling. 

EDIT2: just to be clear, the thermostat for this zone is set at 40F. I've also tried taking the thermostat off the wall, but the T3 call still lives on and the zone remains open. The wires do not appear to be shorted on either end, but I guess I can't rule out something in between.

stlblufan

109A_5

Hello @stlblufan,
Is you system wires like the diagram below ? I don't see anything stuck on in your last picture.
Anyways, I would swap the T3 (the original zone 3 problem) with T1 (a correctly working zone) and also Z3 and Z1 wires at the Energy Manager terminals. See if the problem follows the Energy Manager or the external wires.

HVACNUT

It looks like you removed the wire from T3, the light went out, and the zone valve closed.

So it's either a faulty thermostat, a short in the thermostat wiring, or T2 and T3 are switched. 

Intplm.

Might not be a wiring control problem.
@stlblufan
Do you have a flow-control valve on that zone? It sounds like that is the problem.

Roger

@stlblufan , the only way the thermostat light can come on is by completing the circuit, which happens through the thermostat and wiring. @HVACNUT , thank you for your post, you nailed the diagnostic! Faulty thermostat, short in thermostat wiring, or T2 and T3 are switched...
Roger

stlblufan

Thanks guys. I don't think it can be a faulty stat because removing the tsat from the wall doesn't result in any change to the system. I also do not think it could be a switch of T2 and T3 because this issue just started spontaneously a couple of days ago. So it sounds like a short, which will be super fun to track down. Thanks again for everyone's help.

HVACNUT

stlblufan said:

Thanks guys. I don't think it can be a faulty stat because removing the tsat from the wall doesn't result in any change to the system. I also do not think it could be a switch of T2 and T3 because this issue just started spontaneously a couple of days ago. So it sounds like a short, which will be super fun to track down. Thanks again for everyone's help.

Is there only 2 wires? Hopefully there's other wires you can use.
Anyone hang a picture or shelf or something recently? Got vermin?

stlblufan

Vermin could be it sadly. Rural VT.

stlblufan

Also @109A_5 I did switch wiring as per your suggestion and the problem followed the wiring / switched to Z1. 

109A_5

Hello @stlblufan,

OK as long as you moved T3 and Z3 as a set and the problem followed the wiring the Energy Manager is probably not at fault.

The "Buffer End Switch" has me curious. Is there other equipment in-between the thermostat and the Energy Manager ?



If not inspect the wiring closely between the thermostat and the Energy Manager. It maybe chafed or crushed somewhere, like under a staple that has pierced the insulation of both wires going to the thermostat. A multi-meter with an audible continuity test function may help too.