How does the Honeywell hydronic valve work?

Discussion in 'HVAC Heating & Cooling' started by jcaldwell, Jan 30, 2013.

  1. jcaldwell

    jcaldwell New Member

    Jan 28, 2013
    Albuquerque NM

    I posted a question about my Honeywell hydronic valve a few days ago and got no responses.

    It occurred to me that the valve (probably an old version of the 8043) might be working correctly, and I just don't realize it. So, I need to know exactly how it's supposed to work.

    As I understand it, the thermostat calls for heat by sending voltage to the valve motor. It drives the ball in the pipe to the open position, so there is water flow through the boiler. When the motor drives the valve to the full open position, the gear closes a switch to signal the boiler to fire.

    My valve does not appear to close fully when the lever is removed from the manual open detent--provided the lever position actually indicates the position of the ball valve in the pipe. The lever only goes about half way towards the "auto" position. If I manually move the lever from the (approximate) halfway position toward the manual open lock position, I could feel the resistance of the motor and springs. When I let it go, it returns to about the mid way position, with no resistance between that position and moving it all the way to the right (auto) position.

    I removed the motor, and can see that moving the lever to the manual open lock position results in the gear being about 1/4" shy of contacting the switch. That probably explains why moving the lever to the manual open position didn't get any heat to the basement zone.

    When the motor is working (which mine apparently wasn't due to burned wiring), will it drive the gear past the manual open position? If not, it will never reach the switch to turn on the boiler. If the motor doesn't drive the gear past the manual open position, is there a way to adjust the gear/lever so that normal motor drive will actually engage the switch?

    Is the only thing left for me to change the valve?

    As an aside, I don't find any identifying number on the valve at all. I presume it's an 8043 or equivalent (it is about 26 years old), and that a replacement motor would be one for an 8043. The motor doesn't seem to have any numbers that help me identify it, either.

    I'd appreciate any help on this.


  2. Failure2Comply

    Failure2Comply New Member

    Sep 3, 2012
    Commercial HVAC
    Virginia, USA
    If your Honeywell Zone valve is very old a replacement is a good idea. It should contact the end switch when moved to the "manual open" position.
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