Massachusetts Gradual increase in electrical consumption

Discussion in 'Maintenance and Troubleshooting' started by Mort, May 9, 2024.

  1. Mort

    Mort New Member


    We've had a WaterFurnace Series 5 w/ Aurora monitoring since 2015. Ours is a 5-ton water to air system with a ground loop. Over the past two years, I've noticed a change in the unit's average power consumption.

    During Stage 1 heating cycle with fan at 5 (which is what our system typically runs at), power consumption has historically been between 4000 t0 4200 watts for the whole system. Recently, however, power consumption has increased to the 4500-4700 watt range. It is the compressor that is drawing the additional wattage, according to the Symphony monitoring (see attached). I'm making this comparison at similar times of year (entering water temp. is similar and runtimes are similar) - basically, comparing times when I'd expect the system to be performing similarly.

    I was wondering if there are any likely explanations for a change in compressor electricity consumption - is this what happens to older compressors? Might this be a symptom of a problem with our system? Any advice would be welcome.

    We don't have our system serviced regularly - our installer went out of business back in 2016, but since everything has performed as expected, we've just kept our fingers crossed.



    PS. On the attached screen shots, the return air temperature is 0°F because we use Sensi t-stats and they don't pass that info into the system.

    Attached Files:

  2. SShaw

    SShaw Active Member Forum Leader

    I don't have a definitive answer, but it doesn't necessarily look like a problem to me. Your compressor numbers only changed by about 15%. The ~4 kW for the compressor looks to be close the the operating specs in the WF Submittal Data document for your unit at your incoming water temp.

    Based on the screen shots, it also looks like the version of Symphony changed (earlier shot lists "fan motor" and later lists "indoor blower.") This is just speculation, but it's possible something changed in the Symphony power calculations.

    Your pumping power looks very high at 472 W on Low speed. Looks like you must be running two inefficient pumps. Your unit has the controls for a variable speed pump, so you could save a a lot on pumping power if you could run your system using a single UPMXL 25-124 variable speed pump. The 25-124 would only use 177 W on High, and less on Low. Whether or not you can use it depends on your loop design and pressure drop of your loop, but the 25-124 should normally be able to support a 6 ton unit.
  3. Mort

    Mort New Member

    This is a belated thanks for your reply. (I had some log-in issues on the site.) I appreciate the tip on the variable speed pump. Jay
    SShaw likes this.

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