Problem with Honeywell hydronic zone valve--replacement the only option?

Discussion in 'HVAC Heating & Cooling' started by jcaldwell, Jan 28, 2013.

  1. jcaldwell

    jcaldwell New Member

    Jan 28, 2013
    Albuquerque NM
    Hi, everyone,

    I am having problems getting hydronic heat to the basement. I checked the thermostat and transformer, which are both good. I put the lever into the Manual Open position for a couple days and got heat to the basement, but with no thermostat control. So, I looked into the Honeywell zone valve. I moved the Manual- Auto lever to the manual open position, and it returns to a center position when released. It never returns to the Auto position, and has no tension between the Auto position and about the center of its travel. The wiring for the motor looks like it's burned, so I'm pretty sure it needs to be replaced.

    The real problem, though, is the lever and the valve opening gear. After I removed the motor, I can see the gear/lever and the boiler activation switch. When I move the lever to the Manual Open position, it is nowhere near engaging the switch to start the boiler. And, as mentioned, when it's not in the Manual Open position, it does not return to the Auto position. It stops about mid way.

    Since the gear/lever will not move far enough to activate the switch, I doubt that replacing the motor will solve all the problems. I can't identify the valve, other than saying it's a Honeywell. No marking on the outside. Only a paper on the inside saying "motorized valve" and showing a simple schematic and switch rating numbers. It's a 24vac unit, with 2 yellow wires to the motor and 2 red wires to the switch, so it's probably an 8043 (or, more likely, an earlier version, since the install was in 1985-6). I don't know if the system has to be drained to replace the valve, or not, and I'm certainly not going to try taking it apart until the weather is warm and I can afford to drain the system if required.

    Is there a way to adjust the gear/lever? Or am I doomed to replacing the whole valve?

    Thanks for the help,

    Last edited: Jan 28, 2013
  2. cjpcjp40

    cjpcjp40 New Member

    Mar 7, 2013
    Not sure if you are still looking for a reply, but I've just encountered the exact same problem with my Honeywell zone valve. It's the 8043 model and it is brand new, replaced because the previous valve was sticking.

    Our repair techs couldn't track down the problem so I ended up having to learn the whole system myself to diagnose this. Yes, the gear will move and open the valve, but will not touch the actuator switch with enough force to depress it. Very annoying problem. I currently have a washer taped to the lever to bring it closer, but even that is an intermittent solution. According to the videos I've seen online, replacement is recommended. Good info from the video below: (if they will let me link here, not sure) It is on YouTube under "Port valve diagnosis and repair".

    I am likely going to replace the switch, but first I'm going to try WD40 on the gear box to see if it's just slightly sticky. I've already given Honeywell a blast over this one. They were terrible with their tech support for me when I was looking for the problem. My gear lever will touch the actuator, so it looks completely functional, so it was quite tricky to figure out. Our valve doesn't require purging the system, so replacement is not going to be too bad. One plumber said if the the unit has a 'nipple' on the case, ( a small protruding, rounded button sticking out of the flat metal surface) it means that it can be swapped out dry. Not sure if that's the case or not. There are good videos online about doing the repair, though.

    Good luck.
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  4. Tom Sawyer

    Tom Sawyer In the Trades

    Nov 29, 2010
    In the manual position the valve will only open and allow flow. It will NOT start the burner and if it did, what would shut the burner off? Dooohh Taqco's and everyone elses valves work the same. manual only allows flow. to run the burner you have to swap wires around on the aquastat. IE, the thermostat needs to call the burner relay instead of the end switch on the zone valve.
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