Need To Reinstall Load Shed On New 2-Stage Heat Pump

  1. I recently replaced my heat pump with a new American Standard 2 stage heat pump (4A6H6) and variable speed air handler (TEM6) and an AS 824 thermostat. My old system was connected from the outdoor unit to my Generac transfer switch which has an equipped 24v load shed module. My old system was a communicating system and when my generator was installed they ran a 2 conductor thermostat wire from the outdoor unit to this module. I now assume they load shed the 24v power to the ODU.

    When installing the new system, I was told that since this was a 2 stage unit they could only load shed stage 1 or stage 2. I didn’t think this would shed much load and didn’t sound right so I told them not to hook it up. I have since done some research and found that it is possible to interrupt the 24V red wire at the ODU as was apparently done before. I still have a few questions and concerns about this.

    If the unit is running when the load is shed will this indeed shut it down or is the control board also getting power from the call for heat or cooling wires from the thermostat? Is this safe for the electronics on the ODU control board? I know electronics get power interruptions all the time but it can be hard on them. Would I be better off calling my generator provider to install a Generac Load Management Module installed at the service panel and load shed the 240 volt for the ODU? I think I’m correct that if I shed the 240v that the 24V to the control board would still be powered by the air handler’s transformer thus no hit to the control board. It would just close the 240v relay but no power. Maybe I’m over thinking this.

    If the 24v solution is OK my HVAC guy is coming back to install a hard start kit so I could get him to connect it up to the existing wires to my generator panel.

    No need to suggest that I load shed the air handler or heat strips. That is a different discussion.

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