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work that proved unnecessary
Thursday, September 2 2021
The power outage was still ongoing when I awoke, but I was planning to go into the office today, so no problem.
By about 9:30am, I realized I would be the only one in the Red Hook office today. Around that time, Gretchen told me the power had come on back at home. It was a cool, sunny day (at least by the standards of early September), and I wanted to see how the solar controller was working with its new zone valves. So a little before noon, I decided to drive home and work the rest of my day there.
Unfortunately, the one zone valve actuator I'd installed was not being energized by the solar controller, and it was difficult to figure out why. Perhaps the old Grundfos valve hadn't failed at all; perhaps the problem was the relay that controls it! Actual testing showed that the old Grundfos zone valve was indeed still good, but I was happy to have replaced it all the same; now next time the actuator fails, I'll be able to get a replacement at a big box store (instead of trying to find an increasingly-old part on eBay).
And then I realized something interesting: the actuator motor & gearbox used by the Grundfos zone valve is actually the same as the one used in the commodity Honeywell zone valve. But the actual valve and linkage mechanisms are completely different. The Grundfos behaves like a globe valve, where the mechanism presses a rubber disk over a hole to stop the flow, whereas the Honeywell valve has a rubber ball on an arm that the mechanism swings into place over a hole to block the flow. This means I actually can replace the parts most likely to fail on a Grundfos zone valve without buying a whole new (and hard to find) actuator. But the process of taking a Grundfos zone valve apart and putting it back together is messy and difficult; I'd much rather rebuild a Honeywell actuator given a choice.
After my workday was done, I could concentrate completely on what the problem was with the new Honeywell Zone valve. I soon determined that the problem was not the relay that controls it. There was a 30v AC signal that relay should've been receiving that wasn't present, and without that, it couldn't energize the valve. Further tests (using a multimeter) revealed the problem was due to the signals around the hot water tank's built-in thermostat, can be both disconnected and bypassed by various things I've added to the system over the years. The bypass is handled by a relay that fires in situations where I trust the solar controller to superheat the water (that is, make it hotter than the thermostat normally allows). There's also a switch to disconnect the hot water heater for some purpose I've subsequently forgotten about. At some point in recent weeks, the thermostat became completely disconnected, meaning that the hot water tank could no longer "call for heat," and that was the source of the missing signal on the relay. I could've fixed that with seconds of effort, but instead I'd gone and spent hours of unpleasant effort to swap out zone valve mechanisms. Still, it was work I would probably have to do eventually anyway, so it's good to have it done.
I'd eaten a wad of schwaggy old cannabis (it was mostly leafy shake from the bottom of one of my cannabis jars), and it started kicking in while I was still working on figuring out the wiring in the basement. The effects ramped up a little beyond where I typically want them to go, and it put me in the mood to watch teevee with Gretchen again. We'd watched all of The White Lotus, so we watched the first two episodes of a comedy series entitled The Other Two. It was pretty good, especially the scenes involving an eleven year old makeup artist who is so good at what she does that she is easily mistaken for an adult woman.
[REDACTED]
The two kinds of zone valves. On the left is a typical Honeywell valve, with its aluminum mechanism cover removed and its ball-on-an-arm mechanism shown below it. On the right is a Grundfos-style MZV valve (confusingly labeled "Honeywell" because this one was actually made by Honeywell) with its rubber disk-on-a-plunger mechanism shown below it.
For linking purposes this article's URL is:
http://asecular.com/blog.php?210902 feedback
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