Thermal Actuator, Four-Wire

I replaced three faulty Wirsbo telestat style thermal valves with this Uphonor valve.This valve comes with the adapters to mount this valve to the various manifolds listed. As I was unsure what MANIFOLD style I had I called Uphonor customer service. The gentleman was extremely helpful and explained to me that if you have what is referred to as the "old style" Wirsbro manifold, it is identified as such by "Wirsbro" being CAST into the body of the manifold. To connect this valve to this style manifold, discard the three adapters included with the valve and utilize Uphonor VA33 spacer ring ONLY, available here at Supply House. In fairness, I should say that Supply House may have been able to advise me of this but I'm one to just call the manufacturer when able. Shipping time from Supply House was excellent. Valves have performed flawlessly since installation.

I have Wirsbo/Uponor radiant floor heat in my house, which originally had the MVA actuators (motorized, also called "Tele-stats") on a 3-zone manifold. They were wearing out after several years of use, so I ordered these new thermal ones for replacement. Like other reviewers here, I have found two major problems with them: 1) The plastic adapter collars are poorly made, so the actuator will easily come loose from the manifold. 2) They take about 6 minutes to open the valve after applying power, and about another 6 minutes to close the valve after removing power; which is causing major disruptions, especially with my garage heating loop. I spoke with a technical representative at Uponor headquarters in Minnesota in January 2018, and confirmed that all their motorized valve actuators are no longer made; and they plan to never manufacture them again. My recommendations: -- If you're lucky enough to be reading this before you buy Wirsbo/Uponor proprietary manifolds, DON'T DO IT! Buy/build a generic brass or copper manifold assembly, and plumb up separate Honeywell (or other motorized) zone valves such as the 4000 or V8043 series. (I have Honeywell motorized zone valves in other parts of my system, and have been very happy with them over many years.) -- If, like me, you already have a Wirsbo/Uponor proprietary manifold with the built-in valve plungers... plan to limp along with the new thermal actuators until you can dismantle the whole thing and re-plumb with a non-Uponor manifold and separate motorized zone valves as above, and buy the necessary fittings to match your existing PEX tubing. (You could also order one of the Honeywell MZV520-RP actuators, and see if it fits your Wirsbo/Uponor manifold -- I'm going to try that.)