A number of years ago I installed an Apricus Solar Hot Water system. I did not install a booster but kept the Off Peak system attached. If I am likely to run out of hot water I simply go out to the switch board and turn on the Off Peak power and in the morning I have hot water. Been doing this a lot this year.
The Apricus HWS has a control box attached to it that has a temperature sensor attached to the tank and another to the solar unit. It doesn’t really care what the water temperature is in the tank, it simply compares the temperature from the roof to the inlet valve. If the temperature differential is appropriate it pumps water through the system increasing the water temperature. The control unit also uses the system to make sure that the roof system does not freeze. I have been advised that I should not leave the Off Peak system switched on all the time as it will hide any fault in the solar system.
So, how to automate the turning on/off Off Peak heating when the HWS has not gained enough heat through the solar system during the day.
The circuit breaker for the Off Peak HWS is 20 amps. The HWS 3600 watts. I think the system is operated by the receipt of a turn on/off signal from the electrical company. I am assuming that if I was to put a multimeter on the circuit breaker it would show NO power unit the meter received the turn on signal. This obviously may vary and is not something I have control over.
I know that if the temperature at the inlet valve is about 41 Deg Celcius that the water is hot. My Apricus HWS shows this temperature after having the Off Peak working all night.
This tells me I need a switch to turn the power on/off and a thermometer to measure the temperature at the inlet valve. As I assumed earlier, to put a switch of some sort in line will mean that it has no power to it until the electricity company turns on the system via the meter. Therefore a wifi/zigbee based system will have to reconnect each time the power is turned on and then run an automation based on the temperature at the inlet valve - turn power on/off to minimize electricity usage.
So what hardware do I source for my electrician to install for me? Any other advice?
Thanks
Laurie