Need some advice on wiring boiler zone valves

Steve6662

I have a boiler system I'm trying to wire that hasn't been wired correctly for quite some time. I'm a DIY'er but have some experience with HVAC. I have a system with 3 thermostats and 3 zone valves. 2 zones having 8043E1012 4 wire valves, and 1 Taco 3 terminal valve. I'm using a wiring diagram i found on the net that i thought was most similar to what i was trying to accomplish. The boiler has a Honeywell R8285D5001 50VA transformer control center on it. I spent the day wiring this thing only to burn up the transformer when i was finished. I can not figure out how to incorporate the Taco valve in the wiring. All the information i can find talks about running the wires to the TT terminals but my setup doesnt have TT terminals that i can see. So ive ordered another control center and will try again in a few day. Any help on how to wire the Taco valve into this setup would be much appreciated. Thank you!

hot_rod

Maybe consider a zone control relay box to simplify the wiring, especially with some 3 and some 4 wire zone valves.
The Caleffi ZCR relays have auto resetting thermal links protecting the transformers. No need to worry about frying the transformer.
Most all boilers have a TT or call for heat connection. What brand and model? Should find a wiring schematic inside the boiler. Or online.

Steve6662

T
This is the diagram inside the door of the boiler. Not much information on controls.

hot_rod

See where the 24V thermostat (by others) connects. That is the heat call connection. With a relay box it would be the ZC ZR dry contact.
With zone valves, the end switch connects there.
The 3 wire zone valve complicates it, check the Taco website, they have a good wiring guide that probably shows the blend of 2 and 3 wire zone valves.

Steve6662

Yes i see that. I was going to hook my end wires there on Green and Red. But i think the way i wired the 3 wire valve is where is crossed something up and ruined the transformer. I suppose i'll leave it out of the loop for now and get running without the3 wire valve and just open it manually till i figure something out. Thanks for the help!

Steve6662

I forgot to mention i don't have an external transformer and everything is being run from the transformer on the control center.

EdTheHeaterMan

Try this


You can also add a 5 amp fuse to the R terminal then connect all the R terminal wires to the other end of the fuse with a wire nut.

Two spade connectors and an automotive fuse will do nicely.

HVACNUT

@Steve6662, your drawing is 100% correct, but like you said, you dont have TT. Connect the end switches to R and G on the Honeywell control center. 
Since your using the boilers transformer, break it into 2 steps. Power and end switches. 
Using a zone panel like @hot_rod mentioned would be the pro way to go. No sloppy wire bundles.
@EdTheHeaterMan, you have Common from the transformer to the thermostat R's. Will it work as drawn? Yes, but a little confusing for someone who might not know. 

Zman

The problem you are encountering is that the taco 3 wire is applying power to it's end switch on it's own.
You will have much less brain damage and will be assured that you do not overload the boiler transformer if you install one of these and wire it as instructed in the manual. You would tie it in to your boiler control where the boiler manual shows "24 volt t-stat by others".
Your system will be very simple to troubleshoot and look much more professional.
https://www.supplyhouse.com/Taco-ZVC403-4-3-Zone-Valve-Control-Module-with-Priority

EdTheHeaterMan

HVACNUT said:

@Steve6662, your drawing is 100% correct, but like you said, you dont have TT. Connect the end switches to R and G on the Honeywell control center. 
Since your using the boilers transformer, break it into 2 steps. Power and end switches. 
Using a zone panel like @hot_rod mentioned would be the pro way to go. No sloppy wire bundles.
@EdTheHeaterMan, you have Common from the transformer to the thermostat R's. Will it work as drawn? Yes, but a little confusing for someone who might not know. 

I did not select the boiler wiring design. I would usually do it your way but transformer R is in the wrong place to put it on thermostat R. Since transformer R needs to be used on both the end switch and the motor circuits on the zone valve Dah! Terminal 2!

I also don't recommend spending someone else's money on luxury parts. If it were my customer, I would give a choice of $$$ for labor only to wire this


or $$$ for a zone control panel for easy service in the future. Then let the consumer decide.


For cripe's sake, the guy just fried his control center and needed to purchase a new one. The wiring diagram will work and the fuse is less expensive than the ZVC panel. I believe that is all the OP wanted is the wiring design that will work. Has anyone else offered that?

Electric is color blind. ...and Sharpie makes a marker with a fine point to draw the letter R on the C terminal and the letter C on the R terminal.

Steve6662

Thanks everyone for the help. I appreciate you all taking the time to get me on track.

Steve6662

If i go with the zone valve control module with priority what size wire do you recommend? Is this all wired with just Thermostat wire? Thank you!

EdTheHeaterMan

The Romex or BX wire to supply 120v. to the line-voltage transformers should be at least 14 gauge, but that depends on the circuit breaker feeding the heating circuit. If the breaker is a 20 amp then all the wiring should be 12 gauge.

The low voltage wires should be 18 gauge minimum. Sometimes installers use 20 gauge and smaller. Not a good idea, especially when there are larger (40VA and up) transformers involved. I like to use 18-5 conductor wire on zone valves. You never know when you might need an extra conductor in the future.

clammy

As other have stated save time and headaches and get a taco zone valve controller and your done . Any future service that will be required will be much easier for all concerned . There’s nothing worse then going to a service call and having to deal w some birds nest of wires no body wants to start in messing w that mess when usually u end up straighten it all out because of a bad wire nut or usually ends up being some thing stupid . Do yourself a favor and make life easy . I ve seen people waste hours screwing w zone valve wiring messes and still leaving a mess and shorting controls and transformers out . Take the advice or hire a pro peace and good luck clammy