24V Normally Closed PopTop Actuator w/ Terminal Block & End Switch

Had 1 bad actuator in a system serving 3 heating zones. Uh-oh, call the HVAC guy and grab my checkbook. Last zone valve service call I had cost me $300. I knew the either the actuator or the zone valve itself was bad because you could call for heat from the thermostat and the boiler and circulating pump would switch on but cut right off 5 seconds later. Guessed it was the actuator and not the valve because in 25 years many had already been replaced. Well the valve cost me $50 from supplyhouse. It was ridiculously easy to replace. Just press the black lever on the back of the old one and it slides off. Place the new one on the old valve stem and slide it into place. It worked perfectly and solved the problem-for $250 less.☺️ This is not brain surgery and shouldn't cost $300 for a 45 minute service call. But then that's capitalism, you just have to make a 500% profit on a job or it's just not worth doing. Wrong! DIY.

I have used these valves on my radiant heating system for over 10 years. I have had a persistant problem with the valve failing due to stripping of the plastic gear segment. The only valve that fails is the one on my indirect hot water heater. It is exposed to 170 degrees F from the boiler, while the zone valves for the floor heat only see 110-120 degrees because the water is tempered before it goes to the floor system. The pinion gear on the valve is barely engaged with the last tooth on segment, in my view a questionalbe design. Also the motor is in stall mode whenever the valve is open and this adds to the heat load the valve sees so I think that the combination of these factors puts it too close to the 200 degree rating of this valve. I've had four failures so far. I think the segment needs to be a higher temp material and better engagement with the pinion.