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Honeywell zone valve v8043e1012

Zone valve was turning when I called for heat. Wasn't engaging boiler to turn on. When I rotated dial, boiler would come on and produce heat. I was thinking zone valve end switch. I replace the whole powerhead. Worked for 2 or 3 weeks fine but it seems an intermittent problem that the valve doesn't fully engage to start the boiler. When I rotate new valve it starts boiler. Does the gold part where you sweat it into the zone go bad?


  • spoon22spoon22 Member Posts: 32
    It can go bad but unlikely the cause of the end switch not Making. Check all end switch connections could be a bad connection at other valves or tt on aquas tat connection if all checks out then probably just replace entire zone valve
  • hot_rodhot_rod Member Posts: 12,961
    Do you mean the manual open "lever" on the end?

    There could be something stuck inside the brass body that prevents the valve from opening far enough to make the end switch.

    Check the voltage to the valve, 24V transformers these days can read anywhere from 22- 30V.

    As spoon22 suggested un-do and remake all the wiring connection. A loose wire may read voltage, but not carry enough current to drive the motor.
    Wire nut connections are also suspect, over-tightening them can break the conductors up inside.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • gmamgmam Member Posts: 9
    Not the manual open lever. The unit little wheel sometimes doesn't go all the way to make the zone start the boiler. I check wire connections.
  • hot_rodhot_rod Member Posts: 12,961
    This valve? Where is the little wheel you are referring to?

    Under the cover it should have a Syncrous motor with a brass pinion gear, screwed to a plate, engages a sector gear, to move the Buna ball inside the brass body.

    Unless you have removed the cover from the end of the motor, and exposed the inner workings, I'm not seeing a wheel?

    Here is the valve and a pic of the parts under the hood.

    It didn't use to be you could "make" the end switch on HW valves without the motor running all the way to the end of it's rotation, maybe that has changed.

    If you move the manual lever at the end to open does it call the boiler or pump on? If so the end switch is okay and something in the wiring may be amiss.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Robert O'BrienRobert O'Brien Member Posts: 3,174
    The lever the ball is attached to binds, preventing the valve from opening enough to make the end switch.
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  • gmamgmam Member Posts: 9
    The wheel I am referring to is under the zone valve cap. I will check wiring. I will check manual lever to see if end switch gets engaged. If the ball binds which is what appears to be occurring as it doesn't happen all the time I take it the brass body must be changed or is there another possible solution?
  • hot_rodhot_rod Member Posts: 12,961
    You can replace the base, which includes a new ball, shaft and o-rings. The o-rings on the stems get hard or sticky after time. Then they either bind up, or leak. Four bolts remove the plate from the brass body.

    The other option is to replace the whole valve, but that requires soldering in a new body.

    Or a Caleffi retro fit that presses in.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • gmamgmam Member Posts: 9
    Thanks and great pics.
  • Mark EathertonMark Eatherton Member Posts: 5,843
    It sounds more like either a weak transformer not supplying high enough voltage (doubtful), or possibly a bad wiring connection (more probable) somewhere that is limiting the power, thereby causing it to fall short.

    One would also have to wonder what the water quality is like in the system. As Robert pointed out, it could be sticking.

    I am with HR, I don't think I've ever seen a wheel, other than the Syncron motors flywheel, which isn't supposed to be exposed. And I also agree that I have NEVER been able to make the end switch by propping it in the open position. You can make it close, but you have to FORCE the end switch real hard to the open position, and then it only makes the end switch for a second, before it rolls back and the switch opens. I think this is intentional on Honeywell's part. I don't think they wanted their end switches made during a manual opening. It's not intended to be used that way, and if inadvertently left in the manual on position, would cause over heating. Normal use is temporary, and relies on other functioning ZV motors to make the call for heat.

    If you do decide to replace the guts, be prepared to get wet, and be prepared to purge the air out of the connected circuit. If you're not comfortable getting in to the wet side, hire a pro.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
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