Thermal Actuator for Mr. PEX Manifolds (4 Wire)

The valve comes partially open, so if you want to test it expect it to be open until it is powered on and then allowed to cool. The first time it is powered on it will make some snap and crackle noises til it's fully open. Then once cooled it works like one would expect (normally closed when the wax is not hot) . Takes about 30seconds to a minute to be fully open. Will be partially open and some flow in 15-30 seconds after receiving power.

Disappointed that originals only lasted about 10 years. I'm not holding my breath that replacement model will last any longer. But as another reviewer said, it's easier to replace failed actuators than replace the entire manifold with a different system. When the original actuators started failing I contacted Mr PEX company office and was able to talk with the owner and person who seemed to have designed the system. He was helpful, but admitted that the brass valves that are controlled by these actuators fail and start leaking water. The water can then get into the actuator and that seems to have caused the failures of the actuators. This is more likely when the manifolds are set up so that the actuators are below the valves instead of above the valves. I would recommend anyone planning a new system to have the actuators above the valves. I'd also suggest Mr PEX should not be saying the actuators can be positioned in any orientation. A "work-around" to this problem would be to pre-emptively replace the brass valves before they start failing and leaking into the actuators. The valves are a lot cheaper than the actuators. Another problem I had with the original model actuators was that the adaptor rings which came with them may not have been the correct ones because the actuators would occasionally pop off of them. So far, the new adaptor rings (VA-10 for brass manifold) for the replacement actuator seem to be working with no popping off. Note that the stainless steel pin in the brass valve that gets pushed by the actuator to open the valve is actually adjustable for how far in or out it is in the resting (non-actuated) state. There was no mention of this in instructions, and it might be helpful to adjust it for proper operation so that valve closes fully when actuator off, but there is 0.5mm of the actuator cylinder showing beyond its casing.