Taco ZVC406-3 EXP possible relay burnout...

john p_2

First let me explain my system. It is a Utica ub90-150, with a Weil-McLain Gold Plus 40, 6 honeywell zonevalves, Taco 007-F5 and the Taco ZVC406 EXP. Last night came home to no domestic hot water. Go to the boiler and see all zones are calling for heat but boiler is not running. Turned power to the boiler off then back on and it fired up and shut down on temperature. The circulator is working but the zone valves are not opening on a call for heat. I opened all of them manually and everything works fine. I would think bad relays on the panel no?? And if so are they replaceable(snap in/snap out) or soldered in and need a new panel?

Steve Whitbeck

boiler

Is the indirect one of the zones ( has it's own zone valve )

If it is piped as a zone just like the heating zones is the priority switch on the Taco zoning panel turned on?

I think that Your problem is with the boiler - It locked out -

When You turned the power off to the boiler and back on You reset the lock out.

If the indirect has a seperate pump then it sounds to me like the system was working properly when You reset it. The heating zone valves were closed because the indirect had priority.

john p_2

Taco ZVC406-3 EXP possible relay burnout...

yes it does have priority feature but it wasn't on at the time of the problem.

john p_2

Taco ZVC406-3 EXP possible relay burnout...

also, yes it is one of the zones, no separate pump for the indirect.

kcopp

It has happened...

be fore on 2 jobs of mine. First time one of the zones flat-out would not work after being fine for a month or so. Another time it was a power surge that has taken out the zvc control more than once...but that is a power supply issue.