Virginia WF Series 5 - How can I stop water flowing when the unit is in Lockout

I've got a WF Series 5 running open loop, it's been working great for years. Recently, I've gotten a few high-pressure lockouts recently due to an issue we have with the incoming water flow being a bit low at times - we're doing pump-and-dump from a spring fed reservoir, and I think there's a clog in the foot valve where water enters the system in the spring box. I'm working on resolving that this weekend but was wondering if there was a way to prevent water flowing when the WF system was in lockout.

The thermostat is wired through the loop valve, so that when the thermostat calls for heat/cool, the loop valve opens, and once completely open, then thermostat call passes on to the WF. When the WF is in lockout, the thermostat doesn't know this, so it keeps calling for heat/cool, the WF never kicks on, and the water flows forever until someone notices the system isn't working and manually turns the thermostat to off.

I see there's a "L" terminal where the thermostat gets wired - I'm assuming this goes high when there's a lockout event, but the manual didn't really detail this, and I didn't get a chance to measure the "L" terminal during an actual lockout event. I was thinking it might be a good thing to run this into a relay to kill the thermostat call feeding the water pump during a lockout, or is there a better way to do this?

I do controls automation as part of my job, so adding in some sort of 'excessive run time' sensor externally would be a fairly easy external way to deal with this but leveraging existing signals would be ideal.

Thanks,

AndrewY

 

You can search the 5 series installation manual. There is a LO (lockout) terminal on the ABC board. Manual says LO is turned ON during a lockout fault. Behavior is determined by SW2-7. I think you'd want to choose continuous to connect to a relay.

1. SW2-7 Lockout and Alarm Outputs (P2) – selection of a continuous or pulsed output for both the LO and ALM Outputs. On = Continuous; Off = Pulsed

 

Using the “L” lockout signal to break a thermostat call will cause an endless cycle of attempted restarts with control board time delays if lockout conditions still exist. Breaking the thermostat call to the control board will reset the lockout and open the valve.

Your best solution depends on what type of loop valve you have. It is better to have the unit control board provide the signal to operate the loop valve. The thermostat doesn’t know what the HP unit is doing. I believe the thermostat calls should wired to the control board not the loop valve.

A fast opening valve can be wired to the Acc Relay on the ABC board with dip switches set to “Run with Compressor”.
Do not set dip switches to “Slow Opening valve”. For some reason at this setting, the Acc Relay remains on during a lockout.

A slow opening valve can be powered by the “CC” terminal with the slow opening valve end switch then powering the compressor contactor. I caution you here that the mechanical end switch on some valves can fail closed. Also some Waterfurnace units may have Advanced controls with “Compressor Monitoring” that may lockout if the compressor start is delayed too long

What valve are you using?

 

I'm using Taco Geo-Sentry valves. If I recall correctly, the thermostat Zone 1 call goes into the terminal on the valve electronics, through the valve end switch, then into the geothermal unit. Same for the zone 2 valve.

So based on the first comment here, I could wire the LO output into a DPDT relay, then use the relay's NC terminals to break the thermostat stage 1 and 2 calls prior to them hitting the valves.