Waterfurnace Symphony Measurement Accuracy?

Discussion in 'General Discussions' started by IsItForMe, Nov 19, 2018.

  1. IsItForMe

    IsItForMe New Member

    Hello again,

    I’ve decided to move forward with a WaterFurnace 7-series + water-to-water for domestic hot water. In my obsessive research mode, I dug up this study:

    https://www.nyserda.ny.gov/-/media/...-Water-Furnace-Geothermal-Heat-Pump-Sites.pdf

    On page 60, it states:
    “5.1 On-Site Verification
    At two houses (covering three heat pump units) handheld instruments were used on-site to verify the Symphony readings. This preliminary comparison showed the following overall trends for the Symphony readings relative to our handheld instrument readings:
    • Loop flow rates were higher than expected by 10-15%.
    • Compressor power was lower than expected by approximately 10% for dual stage units and
    higher than expected by 9-15% for the inverter driven units.
    • Fan power readings were within ±10%.
    • Pump power readings were based on the pump current and were found to be correct for the one
    variable speed unit with a variable speed pump; however, they were incorrect where unexpected
    pumps were used with separate control relays that bypassed the Symphony system.
    • Auxiliary heat power was lower by 9%.
    • Loop temperature differences were very close to the handheld readings.”

    This study was published about a year ago, and the systems whose readings were compared to handheld metered consisted or an enormous sample of two.

    Any thoughts on this? Is anyone here aware of further investigation into these discrepancies?

    I know that many people rely upon Symphony reporting to understand their electricity usage.

    Thanks - Brad
     
  2. nc73

    nc73 Member

    People see the numbers and are wowed. I like old school, less stuff to break. If the bills are low, why worry about the details?
     
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Yep....we were very involved in the study. One of the intents was to verify the symphony system in the field, which was tougher than thought. Specially with the variable speed and the electronic expansion valve, the delta T, which is crucial for the measurement of the heat extraction, was +/- 40% within 10 seconds when measured inside with needle probes inside the pipes. The expansion valve was "hunting". It averaged itself out over time, thus confidence is high for the average values, but instantaneous numbers are unreliable. Similar with the flow, symphony flow meter showed one number, the $4000 ultrasonic external flow meter showed another number, and the pressure drop was measurement showed a 3rd number. They averaged themselves out, and were very close, on average, but certain fluctuations we still could not explain.
    I came to the conclusion that the symphony is within 3-5% accurate, which is as good as it gets.
     
  4. IsItForMe

    IsItForMe New Member

    Doc - Thanks for the helpful response. I appreciate it once again.
     

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