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Omnistat2 technical documentation

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    Omnistat2 technical documentation

    So I put down my money and bought a RC-2000 in black. When I pulled it out of the box I knew I made the right choice. Beautiful looking unit.

    Then I tried to hook it up to my traditional single stage gas furnace. The unit would power up for 1 second, power back down, and repeat. The 24VAC power supply of my furnace could not supply enough current. I confirmed this theory with a volt meter.

    So I contacted HAI technical support email. They responded with good info in a couple hours. It seems this stat draws anywhere from 15mA to 60mA depending on illumination intensity and color. I will need to get a new 24VAC supply.

    I also asked about protocol information on the RC-2000. They provided the enclosed pdf document. The thermostat can not initiate communication, that was a disappointment. But it appears almost all of the graph data and other energy information can be pulled out of the ~250 accessible registers. Baud rate up to 9600 should work fine.

    Attached Files

    Mr Spock,

    I have been using 3 of the Ominstat2s for a few weeks and they are very good. Previously I used some programmable (non-communicating) stats that the HVAC installers wired for single stage heat, despite my furnaces being 2-stage units (Trane XV90). When installing the Omnistat2s, I discovered that the installers didn't properly jumper W1/W2 at the furnace to allow the furnace itself to control 2nd stage firing (based on built-in 10 minute timer logic). Thus, my furnaces were never using stage 2, no matter how distant the heat set-points from ambient temperatures.

    Anyway, I wired the new Omnistat2s (with 6 wires versus 5) to control both heat stages, and it works well. Temperatures are much more consistent in my house than before. The Ominstat2s are very configurable. For my Trane systems, the proper setting is "Conventional, auto-changeover, no call for fan with heat" since the furnaces control their variable speed fans.

    I have verified PC - Omnistat2 communications with a terminal program too, but not yet tried the HAI thermostat plug-in with HS. My understanding is that the plug-in works with these stats to control any functions that also exist in the older HAI stats, but you won't have access to the advanced features of the Omnistat2 such as run-time logging. I don't think these are too critical for me. As long as the plug-in runs reliably, I'll be happy.

    A note about HAI documentation: I think they make it available to anyone who registers on their site, so I'm not sure if it's good practice to post it here?

    Happy New Year all!



      Hi Don

      Glad you had good luck with it. I know ben also loves his. It's a really great stat.

      Hope HAI does not mind I posted that doc. I did not register. Just emailed support and asked for it.

      Eventually someone (maybe me if I work on my VB skills) will write a detailed plug in for this stat to get the full use out of it.