Quote:
Originally Posted by jeff5may
...you're on the right track with using IC 8 to assume command of the outdoor unit. Applying voltage (from IC1 pin 20) to pins 1 to 6 will activate the brawny components on the output side of IC 8 reliably.
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Sounds great. Is it OK to connect directly, or should I use some kind of resistor? I can see that this would be the perfect way to deal with the 4-way, since I have no plan at this time to use the unit for cooling.
Quote:
Originally Posted by jeff5may
You can do this directly or indirectly, which begs another question: Where will the arduino controller live? Will it be a replacement for the microcontroller in the ashp only, or will you want it to do more?
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I really like randen's suggestion to put a programmable thermostat on the output (actually I plan to use an output tank, so that will be where I would attach the thermo).
I have so many projects in the air already, that I need to limit complexity as much as possible.
Quote:
Originally Posted by jeff5may
Like Xringer said, you may be able to get away with faking the test mode button to indirectly assume control of IC1 and all of its built-in ability. IMHO, this would be the way to go if it works. If the unit faults out after 5 minutes, just feed it another keypress train after 4:45 if you want it to keep operating. If not, let it shut down on its own. Then again, it might just run and run until you tell it to stop. It just might be the ticket: less is more. Can't hurt to try.
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Yeah, this sounds great. One problem with that approach that I'm wrestling with is, assuming that the TEST KEY is a toggle (ON & OFF), then how will the system know what state the heat pump is in? I mean, if the process skips a beat, then the unit will go OFF when heat is required, and go ON when too much heat has been reached.
Quote:
Originally Posted by jeff5may
If you decide to directly switch IC8 to control components, you will lose all of the marvellousness built into IC1. All the "what if's" will have to be accounted for and built into your control sketch. You could do this remotely with a 1-wire addressable switch chip or directly with an arduino board.
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If I did a hardware solution, and used a temperature sensitive snap-disk switch as a run-away heat limiter, and a refrigerant pressure limiting switch, I think I'd be covered.
I don't know which one would be the least hassle in the long run.
Quote:
Originally Posted by jeff5may
...The sky's the limit...
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Not for me, the sky is already filled with too many flying projects!
I think I am becoming the Samouri EcoRenovator, chop, chop...
Best,
-AC