AdrianP

I was unsure how accurate the digital counter would be for the ASHP so (at great personal distress due to lack or internet access over 2 hours 😞) I opened all of the fuses except for the ASHP and photographed the silly clamp on joke, the digital meter and the consumer meter outside over around two hours. Bearing in mind that the digital meter is only changing one digit every 26 minutes it was not massively accurate at this low power usage but the digital and consumer unit were similar and the clamp on device was away with the fairies. An extra (unphotographed) measurement made the digital and consumer results match. The recorded usage was 31 vs 31 vs 235W for the consumer unit, the digital meter and the clamp on device. The digital meter is therefore accurate when measured over a reasonable time. This was over a reasonably warm mid day period, and is lower than my results yesterday (mid-day to late evening), so it may be that the unit is trying to minimise power through some form of monitoring. Overall, the power usage is much less than I originally thought from the joke monitor.

I found this website after the antique NPower supplied clamp on power meter showed that we had about 240W usage, with hot water and heating off, even with all of the breakers switched except for the ASHP. We have a PUZ-HWM140VHA i.e. 14kW R32 single phase. According to the meter (originally installed with the unit and looking very similar to the picture on a previous page) it went from xxx87.57 kWh at 1025hrs to xxx88.09 kWh at 2028hrs. That is 0.52kWh over 10 hours or 52W. I also found a document online, called Ecodan ATW data book V5.3 (72 Mb so cannot upload) which gives all of the tech data for current machines and it lists a hermetic scroll compressor for the 11.2 and 14kW units, but hermetic twin rotary for the 5.0 and 8.5 kW units, which may explain the differences between unit types. I may, if I can persuade my wife to go out for a few hours due to lack of internet, repeat this for three hours tomorrow and check the meter reading outside.