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taco zvz404 to circulator?

The Taco has been working flawlessly since Nov. on a three zone system we put in as a temporary fix for 3 sunken boilers in my apartment building. Was messing with the boiler his weekend to rig a male plug into the boiler wiring so I could run it off a generator or battery. Works fine either way.

Only thing I noticed: The circulator continues to run after the thermostats has been satisfied and all zones valves are closed. I checked the wiring diagram and it appears that the zone valve control should be wired directly to the circulator via the pump end switch. I swear it wasn't runing like this at the time of install and that I read in the manual that we didn't need to hook up the circulator when the electrician and I were trying to figure out the wiring. But we were both pretty tired post Sandy so who knows?

Time for adult supervision or should I just switch the circulator wires from the New Yorker's control board to the Taco? Looks pretty straightforward, but I'm not sure what that's going to do to the Honeywell relay it is plugged into.

Thanks in advance.


  • ZmanZman Member Posts: 3,517
    Post Purge?

    Many boilers have a pump relay with a time delay. This is referred to as "Post Purging" the pump. It helps dissipate some of the  boiler's heat and avoids the high limit tripping on error. Some will run 1 minute, some longer. Does the pump turn off eventually?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • LittlelandlordLittlelandlord Member Posts: 8

    Thanks that makes sense. The docs on the New Yorkers don't say anything about post purging, but yah, gotta assume that's what's going on except the water has to get down to 100 or so before the circulator shuts off. The way I set it up probably would have burned out the pump eventually, no?

    Turns out my problem was that I had the wrong docs for the Taco zone controller. Mine were dated 2006 and downloaded from the Internet. Great thing about the Internet, you can almost always find convincing incorrect information on any subject within seconds. Taco apparently reconfigured the board slightly in 2010 and relocated a couple of connections. Those docs were on the inside of the housing. My method sorta worked, I had the aquastat relay wires connected to where the pump end switch should have gone, but no control on the circulator. Now everything seems to be working correctly with the circulator and aquastat relay wired to the Taco board per specification. and shutting down simultaneously.

    Nice thing about this is that we're all set for a pretty simple install of a Fuelmizer outdoor reset.
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