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Power transient freezes Lochinvar Knight controller
Some small fraction of the time when my backup generator shuts down, there's some sort of power transient that freezes the controller on my Knight KB80 boiler. This is not repeatable, so I can't perform any kind of testing. In addition, the transient is minor enough that nothing else in the house notices it, including $10 clock radios that will reset if you look at them cross-eyed. All the clocks on the appliances are fine too. When I say the controller freezes, I mean it won't respond to anything, including the buttons on the front panel. The only way to reset the controller is to power cycle the boiler. Has anyone else observed this problem,, which strikes me as indicating that the controller power supply doesn't have adequate filtering (which really isn't much for a low current 5V power supply). I've reported this to Lochinvar but gotten no response.
(In case you might be wondering why I've seen this enough to notice, I have off-grid solar and the backup generator automatically starts when the batteries get low, which can be as much as once or twice a week when the weather gets crappy and the sun is low in the sky.)
The best I've come up with for now is to check the boiler when the generator stops. If I'm going to be away for a couple of days, I plug the boiler into a timer which power cycles the boiler once a day to make sure it's never out for too long. I've got a circuit sketched out to detect the condition and power cycle the boiler, just haven't gotten around to wiring it up.