I have a small system with four A3020522 Uphonor zone valves. Out of curiosity, if you have any experience with the things, how long do they last? The first set all ended up cracking their housings after a few years and were replaced. Over the years, I've replaced a couple more for various reasons, and just found one whose end switch is intermittent so I've ordered some new ones which should give me a few spares to have on hand. I expected them to need replacement on occasion, but they only seem to last 3-4 years or maybe a little longer.

What has been your experience?