zoning circulator and zone valve for radiant wiring into taco zvc

CPHNed

Customer had installed recently a new radiant heat zone off of burnham cast iron boiler that was all high temp for baseboard. He used a Taco 007-zf5-9 zoning pump after mixing valve for radiant. he also installed a honeywell V8043E1012 on return to boiler.
I met him and I replaced a honeywell sparco and powertracks zone valves due to corrosion and bad functionality. I put in a Taco ZVC404-EXP-4 and honeywell Zone valves. I am having a hard time with the wiring of the zoning circulator and zone valve with the ZVC.
Can i tee t-stat to zoning circulator and ZVC, and tee end switches from zoning circ. and zonevalve and take that into ZVC and zone valve motor into ZVC? Then end switch to boiler TT? My concern is sending voltage from zoning circ to ZVC (or vise versa) in t stat line. thx all, CPH

CPHNed

I have installed numerous condensing boilers with two temps. using two pumps for each off of primary loop. I have not come across this , where two temps are coming off cast iron boiler . my goal is to use what is there now and have the zone valve and zoning circulator for radiant only working when radiant calls for heat. I left the zone valve open and have t stat for radiant taken to zoning circ. The End switch for zoning circ. i have taken to TT on boiler. i left wiring for radiant zone valve disconnected. So now whenever boiler fires for baseboard zones it is being pumped through radiant. and when only radiant is calling for heat boiler pump is also on.

Dave H_2

I would just put a jumper wire across the R & W terminal of the Zoning Circ and then wire that circ to the ZVC controller.





Dave H.

CPHNed

Thx Dave, could you help me understand your remedy. When you say wire the zoning circ. to ZVC what do you mean exactly? thx, CPH

CPHNed

also, wouldnt the zoning cir. be running continuously if i jumpered the r and w?

Dave H_2

On the wrirng diagram above, the "system Pump" is your pump that you already have. The ZVC controller has a pump relay built in but it is a dry contact, you need to run line voltage to as shown with the circ.
Put the jumper on the circ and the relay in the ZVC control will tell the circ to turn on and off.

Dave H.

CPHNed

I have the original pump, wired inside boiler to boilers relay. Then the zoning circ. that is pigtailed to outlet. Are you saying to wire original pump and zoning circ.(with jumper) to ZVC? Thx for info btw

EdTheHeaterMan

@CPHNed
Try this diagram.
Now, by using the end switch from the radiant zone valve, the zone circulator will only operate when the zone valve is open for the radiant zone and the zone ZVC is operational.
Otherwise, the Zone Pump will operate whenever any zone (the high-temperature zone) calls.

The boiler circulator will operate on any zone calling (Both the Hi-Temp and the radiant) if you leave the boiler circulator connected to the boiler control the way it came from the factory.

Also, remember that the Honeywell zone valve may reduce the amount of flow thru a 3/4" pipe from around 4GPM to around 3GPM. This may be a factor if the 3/4" high-temperature loop has a need of more than 40,000 BTU

CPHNed

Thank you Edtheheaterman, this is exactly what i have been looking for.