Solar PV and heating water

garbeth

Having solar PV installed with a divertor to heat the water in the immersion.

Should I get a timer for the immersion as it’s currently operated by a (sink\bath) on off switch or will the solar heat that water regardless of whether the immersion is on or not

irishchris

garbeth wrote: »

Having solar PV installed with a divertor to heat the water in the immersion.

Should I get a timer for the immersion as it’s currently operated by a (sink\bath) on off switch or will the solar heat that water regardless of whether the immersion is on or not

Depending on the diverter but shouldn't need a timer. The eddi unit for example sends excess pv power that you wouldn't be using to the immersion every time it detects spare power so will turn itself on and off through the eddi. No need for a timer to be fitted and the immersion switch you have should be left on once the diverter is fitted as the switching will be done within the diverter automatically

Charlie-Bravo

The Eddi is the only thing to add there but you need a good bit of excess for it to kick in.

What's your Central heating system at the moment and do you have a zone for it i.e. is it plumbed through a calorifier coil?

Heating hot water via the immersion when you have no excess PV power coming in will be more expensive than using say, a gas condensing boiler through the calorifier coil (I'm ignoring the CO2 negatives here!).

garbeth

Never use the immersion except when I need hot water in the summer to bath the dogs and then it’s on for 15 minutes and off again. If the Switch is left on does it mean that the immersion is always on or is it like my heating in that it’s always on but controlled via the nest

Only have 1 zone for central heating so don’t have separate control of hot water. Burner is probably the next thing to be upgraded.

Charlie-Bravo

Never leave the immersion on, especially on bath!! Joking aside, using the immersion is not the most economical way of heating hot water, try use the boiler in all cases, even during summer (make sure the radiators are isolated).

If you only have one zone, do you have a summer valve at the hot press (could have a gate valve beside the cylinder to manually turn off the rads)?

graememk

Depending on how your house is wired the hot water diverter will most likely replace your current immersion switch.

For example when you have Solar excess, it will heat the sink immersion, and when that reaches it's temp it will move to the bath element.

And if you need to give a boost you do it through the diverter.

Rzeznik

If you have the diverter installed, then yes, you leave the immersion on all the time.
It will only turn on when there is excess of pv power. It will not switch on when there is no excess PV power available.

If it is Eddie diverter then you have a switch under the box to bypass this and there is also an option to turn your immersion on using grid power via app/on Eddie itself.