Zone stuck on

seaverill

My system 2000 with the Digital Manager (4 zones plus hot water) is stuck with zone 3 always on.
Tried power cycling but when it reboots the zone3 light instantly illuminates but the T3 (left side) light is not illuminated. The other zones work fine but the Zone 3 is always on and the furnace continually runs pumping heat to that zone.
Tried disconnecting the wires to that zone (both the T3 and the Z3) but the zone light still illuminates and sends heat to that zone.
Upon connecting a different thermostat and zone to the zone3 connectors the constant heating was shifted to the new thermostat zone so it seems as though it is not a valve being stuck open
Ive already replaced the thermostat (old style rotary dial) to no avail
Does this mean the Digital Manager is bad ? If so, can it be serviced or only replaced?
Thanks for any ideas

EBEBRATT-Ed

Don't know if I am understanding this correctly but if you wired a different zone valve and a different thermostat to the one 3 connections and the problem did not show up on zone 3 then you have a bad thermostat or zone valve.

mjstraw

Energy Kinetics has a downloadable diagnostics tool that you may find helpful.

HVACNUT

I would say there's a short in the thermostat wiring for that zone. 
Somewhere between the Manager and the thermostat, the wires are touching. 

szwedj

While it's possible for a triac in the zone outputs to burnout and stay on (or off), it's not very common and it would not cause the boiler to stay hot and constantly heat that zone. But if the output is stuck on, it will allow that zone to heat while any of the other heating or hot water zones call.

The first thing to try is to shut the power off at the system power switch and pull the right side connecter (outputs) off and cycle the power back on. If the zone output light stays off after powering up, most likely there is a short in the zone outputs somewhere.

If the output light still stays on, shut the power back off, mark the thermostat wires and disconnect them. Next power the system back up, if the light stays off, then there is most likely a short in the thermostat wiring. If the light still stays on after checking both output and input side, the problem is probably internal to the control and will need to be replaced.

If the problem points to a short in the wiring, your heating professional can locate it and correct the issue.

If it turns out that the manager needs to be replaced, depending on the age of the system your heating professional can order a warranty replacement or a remanufactured control with a core credit available for the old one. https://energykinetics.com/system2000-parts-trade-list-price/

Jamie Hall

Not sure I'm really clear on this. If you connect the thermostat wires which come from the Zone 3 thermostat to some other zone (zone 2, for discussion), and connect that zone's thermostat to Zone 3, Zone 3 behaves but the zone which now has the Zone 3 thermostat (for instance, Zone 2) now is the one which stays on?

And the zone 3 thermostat is new (the old round one was probably just fine, but leave that be)?

If you disconnect the wires from the Zone 3 thermostat completely at the controller, what happens?