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Hydrostat 3250 plus Aquastat & Taco ZVC404 Zone Valve Control Wiring to indirect hot water heater

corban
corban Member Posts: 6
edited January 11 in Oil Heating

Regards to all .

First time on the forum .

 Changing the old system to a new one .I got few question please .By the way it’s a boiler system with two zone valves one circulator pump and indirect hot water tank .

On my indirect hot water tank the thermostat  has 4 wires as seen , two on right side from a transformer 24v, two on left go to the Honeywell R845A.

please refresh my memory how that gonna be wired once hooked to the cvz ?

If not mistaken there is a jump wire got to be made on indirect water tank thermostat ( switch) but can’t recall how .

On the other hand is the drawing in pic the right setup for my system?

IMG_1898.jpeg


IMG_1890.png

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 3,095

    I would say this is beyond you , hire one of know .. trust me….Many safety issues ..

    There was an error rendering this rich post.

  • Steamhead
    Steamhead Member Posts: 17,518
    edited January 11

    What does the R845A do? Is there a circulator wired to it?

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • corban
    corban Member Posts: 6
    edited January 11
    https://forum.heatinghelp.com/discussion/comment/1833774#Comment_1833774

    yes it’s wired to indirect hot water circulator .

    Replacing all old controllers To the Hydrostat 3250 plus Aquastat & Taco ZVC404 Zone Valve.

    Just wanna get rid of all the wiring mess to a neat zvc that is gonna run with one new circulator

  • corban
    corban Member Posts: 6
    edited January 11

    system now run off two circulators as the indirect hot water tank was an add on to boiler at a later time .

  • 109A_5
    109A_5 Member Posts: 1,997
    edited January 11

    Hello corban,

    I would think the relay contacts N.O. and COM (orange area) wound go to the Zone 4 (Indirect Temp Control) on the ZVC. The relay contacts to zone 4 act like a thermostat switch closing with the other zones.

    The 24 VAC to the indirect thermostat unit powers the stuff in the Red area. A jumper may be for a different application.

    image.png

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    corban
  • corban
    corban Member Posts: 6
    edited January 11

    109A_5 thank you for your input.

    I was hoping to get rid of the transformer and extra wires that powers the right side in red in a way since the ZVC supply’s a 24v .

    I did something similar years ago but i can’t remember, it was like placing a jumper between these terminals .

    The goal to minimize the wire mess .

  • 109A_5
    109A_5 Member Posts: 1,997
    edited January 11

    If the ZVC transformer has the extra capacity the indirect thermostat could run off it. Not running any power robbing thermostats on the other zones ?

    Personally, I would spread the load across the multiple transformers since they would run cooler.

    The jumper may have been for if the indirect's thermostat has to supply a switched 24 VAC to another device. In this case with the ZVC (zone 4) the indirect's thermostat just needs to supply the contact closure of the indirect's thermostat relay.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • corban
    corban Member Posts: 6
    edited January 11

    Will give it a try from N.O. and COM to Zvc
    thank you

  • pedmec
    pedmec Member Posts: 1,148

    The jumper is probably for the zone valve terminals on the ZVC which has a 4 wire terminal block which is not on this wiring diagram you have posted. if your using a circulator for the indirect. you jumper terminal 3 and 4 on zone 4. if you take out the electronic aquastat and install a residio 4006 aquastat you can just use the two wires on the left and land them on zone 4 of your taco 404 ZVC.

    the other two wires and the transformer can be removed as you don't need to power up the electronic aquastat mounted on the side of the tank. the 4006 is just a switch.

    you also will not need the R845 as you will have your circulator for the indirect wire to the n.o on the single pole double pole (n.o - com - n.c) relay located on the bottom left. this is the terminals that will create a priority on the circulators if you need priority

    corban
  • HVACNUT
    HVACNUT Member Posts: 6,504
    Screenshot_20250111_043211_Samsung Notes.jpg

    The diagram isn't a Taco panel, but same thing. Use ZR,ZC for the end switch on the indirect. Power the right side of the indirect temperature controller constant from the ZVC transformer.

    corban
  • corban
    corban Member Posts: 6

    thanks guys you’re awesome.

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