Quote:
Originally Posted by Ormston
Also a mechanical thermostat could be mounted on the condenser input line and evaporator water outlet and wired inline with the compressor relay coil to shutdown the compressor in the event of over temp/pressure or freezing ground loop water.
Safety circuits should never rely on software.
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I went back to find this post, because it had mostly passed without comment.
I think Steve is absolutely right in saying that "Safety circuits should never rely on software".
I completely agree because every computer device, no matter how small, even the humble 4-function calculator, has a tiny paperclip sized hole for performing a reset, in case their little brain locks up. In the case of a calculator, it's no big deal, but if you're away from home and something in you heat pump system goes crazy (maybe even because of a locked-up cpu), you'll want the security of a non-software provision to prevent damage to the system. I mean I got lucky when I got the brazed plate HX of my dreams for about $90, but if it was in mid-winter, and I needed a replacement for that same HX, it could easily cost me $700... saying nothing about down-time and re-installation hassles, etc.
Best,
-AC