Our EMMA unit was fitted in December 2015 and we reported that it appeared to be faulty in January 2016.
Back in January I noticed on our smartmeter that our grid usage was spiking overnight instead of being low and relatively steady.
I then started to track the EMMA unit as this was the only ‘change’ in the house. At 23:00 each evening the EMMA unit resets its counter that tracks how much energy has been sent to the immersion heater.
And here is a reading just before 23:00
The reason I reported the unit to the Thames Valley Vision Initiative back in January was the amount of energy sent to the immersion heater overnight. This could only have been from the grid as there would have been no solar energy overnight.
The above image was at 07:00.
Engineers duly came in January and tested the unit and said it was working OK, but they did take copies of the above images, promising to to double check if the unit was indeed working OK.
In March, while we were away I decided to track more closely electricity usage and used the website of our electricity supplier (British Gas) where I should have been able to see daily usage, but unfortunately several of the days were not available. However, given that most of the electrical appliances were switched off our usage patterns did seem wrong on the days that I could get readings.
I did some research on the EMMA 4G and its manufacturer, Cool Power Products and this time I decided to have the EMMA unit removed as if it indeed was working ‘correctly’ then it wasn’t working as promised.
The SSE engineer, via Thames Valley Vision, came and requested that before taking out the unit that he check to see if it was correctly installed. He discovered that the monitoring feeds were not correctly connected to the controlling unit and this was the reason why the unit was sending power to the immersion heater even when there was no solar power available.
The engineer corrected the problem and then demonstrated to me that if I switched off the solar energy then the EMMA unit stopped sending energy to the immersion heater.
As we are starting more sunny days and as the unit appears to be working correctly, we’ve altered the timing of the gas boiler warming the water to rely on the EMMA unit only warming the water in the day. Here’s to a sunny Summer and lower gas bills !