PV Immersion Heater over-ride


I'm working on a PV diversion system for my immersion heater. But what I ideally would like to do is have a switch that would allow me to either have the PV diverter controlling the immersion heater, or to have it switched on manually (for those cloudy days when I may need to switch it on). I can't seem to find a double pole, double throw switch that is suitable to fit in a standard switch base.

Can anyone suggest how I could achieve this ?



Robert Wall's picture

Re: PV Immersion Heater over-ride

Why do you need a DPDT switch? All you need to do, if you only want to override it on, is have a SPST switch to short out the triac.

Alternatively, you can use a switch rated at 5 V, and a few mA, and use that into a spare DI in the diverter and modify the sketch so that the triac is driven permanently on when the switch is on.

Which you go for depends as much on where you want the switch to be physically as anything else.

calypso_rae's picture

Re: PV Immersion Heater over-ride

I agree with all those comments from Robert. 

If your diverter is situated close to the CU, and it intercepts the radial circuit for the immersion at source, then it's difficult to see how you could retain the ability to over-ride the system from the remote end near the heater.  The existing isolator at the remote end needs to be permanently switched on otherwise no power will flow. 

Running a lightweight pair to a SPST switch at the remote end would allow you to instruct the processor to apply/remove power on demand.  You could also add a push-button to the box which would bring the output stage 'on' for a set period of time.


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.