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Multizone Hydronic Heating Problem

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djmatz
djmatz Member Posts: 4
I have an odd problem that am not sure how to resolve. Two of my zones do not work when the thermostat calls for heat. The zones valves open but the boiler and pump do not come on to ciculate the water. If a third zone calls for heat the boiler and pump fire up and all three zones get heat. Any suggestion on how to troubleshoot this?

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  • hot_rod
    hot_rod Member Posts: 22,353
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    Do the zone valves wire into a relay box? Or do the get powered from a transformer somewhere 

    Sounds like bad end switch, easy to troubleshoot if you have a relay box

    Do you have a voltmeter?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Zman
    Zman Member Posts: 7,588
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    Are they Honeywell valves? Chances are the end switches are not closing and the powerheads need to be replaced.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • mattmia2
    mattmia2 Member Posts: 9,840
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    did this all happen at once or did one zone stop heating then another? all at once i'd be looking at wiring to the end switches, one then the other over a period of time i'd look at the end switches.
  • djmatz
    djmatz Member Posts: 4
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    Thanks for all the replies. I have a voltmeter, just don't knoe where to start. Where are the end switches located? As far as I can tell all the thermostats wiring (there a total of nine zones) come into the mechanical room, but nothing is labelled
    . I have attached a picture.
  • djmatz
    djmatz Member Posts: 4
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    Ok, I think I figured this out. These are Honeywell valves. Years ago I replaced one of them and I still had the old one. When the valve closes there is a metal tab which is supposed to push against a little black button to close the end switch. This not happening, the tab never reaches the button to close the switch - valve is open but water does not circulate. Is there any way to fix this without replacing the whole unit?
  • bburd
    bburd Member Posts: 926
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    You should be able to replace the powerhead without opening the water side of the valve.

    Bburd
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
    edited November 2022
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    djmatz said:

    Ok, I think I figured this out. These are Honeywell valves. Years ago I replaced one of them and I still had the old one. When the valve closes there is a metal tab which is supposed to push against a little black button to close the end switch. This not happening, the tab never reaches the button to close the switch - valve is open but water does not circulate. Is there any way to fix this without replacing the whole unit?

    @bburd is correct, the actuator (motor and switch assembly) can be replaced if the valve is not one of the original zone valves made before 1980s. The actuators are not connected to the brass plate on the newer zone valves. If you have the older valve, you will need to add the redesigned plate that holds the valve ball on the wet side and the actuator on the dry side.

    https://www.amazon.com/Honeywell-40003918-006-Valve-Power-Conversion/dp/B0067E5URQ/ref=pd_bxgy_img_sccl_2/139-8456933-8346828?pd_rd_w=TpVgb&content-id=amzn1.sym.7757a8b5-874e-4a67-9d85-54ed32f01737&pf_rd_p=7757a8b5-874e-4a67-9d85-54ed32f01737&pf_rd_r=TQ3RCSWS70WVFANY4H0E&pd_rd_wg=Spkba&pd_rd_r=7b8f6a91-66d8-4524-b77b-71d35edae489&pd_rd_i=B0067E5URQ&psc=1

    If you already have the newer valve design, you can just replace the actuator only. There are 2 screws that hold the actuator in place on the valve body.https://www.supplyhouse.com/Honeywell-Home-40003916-026-Replacement-Head-for-V8043E-Zone-Valves?_br_psugg_q=40003916-026 with 4 wires,

    or the https://www.supplyhouse.com/Honeywell-Home-40003916-012-Replacement-Actuator-for-V8043G with the 5 screw terminal connector in lieu of wires. Both actuators are identical insofar as the operation and function.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • clammy
    clammy Member Posts: 3,113
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    Trouble shooting a birds nest of wiring can be difficult being there’s usually not much rhyme or rhythm to it . . It may be easier to just turn up each t stat one by one and check each zone individually . You may also be able to just manually slide the manual handle over all the way and some times it will kick the combination aqua stat circ relay on for a second . I will usually recommend install a taco expandable multi zone valve relay . It neatens up every thing and makes any trouble shoot extremely easy and time saving ,especially when deal w multi zone valve using multi transformers you cross one wiring by accident and your replacing the transformer and wasting time re doing yet another birds nest . When under taking a zone valve re wire I usually use collared cable ties after tracing all wiring and respective piping I will color code both and continue that schemes right back to the zone panel ,it makes being sure your wiring is correct and easy to figure what’s working and not ,just about anybody can figure it out and most home owners appreciate it being they can usually figure out if there’s issue before call for service . A expandable relay will give you the opportunity to easily tie 1 or 2 panels together and a exp panel has some dip switch setting to help customize thing like zone valve exercise pump exercise depending on how your system is wired . I hope this help you out
    Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • mattmia2
    mattmia2 Member Posts: 9,840
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    You could also get that tape that has rolls numbered 0-9 and number the wires as you trace them.
  • djmatz
    djmatz Member Posts: 4
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    EdTheHeaterMan said:

    "If you already have the newer valve design, you can just replace the actuator only. There are 2 screws that hold the actuator in place on the valve body.https://www.supplyhouse.com/Honeywell-Home-40003916-026-Replacement-Head-for-V8043E-Zone-Valves?_br_psugg_q=40003916-026 with 4 wires"

    This is the valve I have. I replaced one of these years ago. For now I have swapped one of the defective actuators with a working one from another zone that I rarely use (that room get warm enough just from leaving the door open).

    When I started to unscrew one of the other ones, water started leaking from the valve body, but stopped as soon as I tightened the screw again. This is a much bigger problem which will require replacing the valve body as well, which means I would need to drain the system, I guess.