Honeywell Zone Valve Problem - I have a Honeywell zone valve (8043E). I have spent time trying to understand exactly how this valve works, and I am pretty close except for one thing: the motor. When the thermostat makes, that causes the slow-motion motor top turn which opens the valve. Eventually, when fully open, a tang presses the end switch to turn on the circulator pump and ignite the boiler (via red wire circuit). Though the thermostat is still closed (because we’re heating), something causes the motor to stop. What is this mechanism?
Honeywell Zone Valve Problem
I can’t imagine it is controlled in any way by the end switch as the only electrical connections to the motor are the 2 yellow leads that connect to the T-stat circuit. When the motor is isolated and 24VAC is applied, it will run until the cows come home. I have tested this. While running, I have grabbed the brass gear and applied resistance. It does not stop; it continues to run. So “resistance” is not the mechanism to make it stop. I don’t believe in magic. What actually causes the motor to stop at the of the valve open arc? Please help! Thanks! Thanks for the question and for visiting High Performance HVAC!! Zone valves are pretty straightforward on how they work. I can’t say about the valve you have right now but all the valves I have worked, along with valves powered by actuators come either Normally Open, Normally Closed, or Modulating. The power to the motors for these valves typically remains constant until the circuit is broken whatever method is used to control the valve. The Honeywell 8043 is Normally Closed. When it is powered up it opens. When the power is removed a spring return closes this valve.
Specifications Sheet - Honeywell Zone Valve Problem
I have read the specifications sheet for this valve along with other specification sheets. Quite frankly, this is not something I have ever thought of. Any zone valve I have worked on or installed, either worked or didn’t work. I can only surmise that there is a mechanism that will allow the valve to open. A mechanical stop built into the valve. The motor energizes and the valve rotates to the mechanical stop (in the open position). The motor remains energized until the thermostat (call for heat) opens and de-energizes the motor. The spring return moves the valve to the closed position. I can also only surmise this question is out of pure curiosity on how the valve works. Since the valve is simple and straightforward on the operation, troubleshooting is similarly straightforward. Installation is simple with both the hot water boiler piping loop and the wiring. It is important that the valve is installed according to the flow arrow. The head should be removed for sweat connections to prevent damage. Once the soldering is completed the head replaced on the valve. Wiring involves three separate connections: The transformer for 24-volt power, the thermostat to provide control, and the end switch to control the circulator pump.
Conclusion - Honeywell Zone Valve Problem
The bottom line answer to your question is the thermostat controls the opening of the valve. When the thermostat satisfies the motor is de-energized and the valve closes by a spring return.
Honeywell Zone Valve Problem
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