Retrofit of solar collection to new unvented boiler

[dornfield]

So, given today's new of a 35% hike in gas prices.....
Perhaps the horse has bolted, but can anyone advise me if it is possible to retrofit a solar collection (either water or electric) to supplement the heating of water in our brand new unvented gas boiler system? It is not an on demand system, but rather a 40KW Bosch Worcester. The tank is 300l. I figure that be the end of next year it will cost more to heat the water in the tank once than I earn in a month. We have a large south facing roof just begging for some form of solar trap.

Any constructive advice?

Cheers,

Brian (Dornfield)

 

[cider]

So, given today's new of a 35% hike in gas prices.....
Perhaps the horse has bolted, but can anyone advise me if it is possible to retrofit a solar collection (either water or electric) to supplement the heating of water in our brand new unvented gas boiler system? It is not an on demand system, but rather a 40KW Bosch Worcester. The tank is 300l. I figure that be the end of next year it will cost more to heat the water in the tank once than I earn in a month. We have a large south facing roof just begging for some form of solar trap.

Any constructive advice?

Cheers,

Brian (Dornfield)

Firstly you get paid very little or you gut your sums wrong.
shame you didnt have a twin coil cylinder fitted it would have only been about £100 150 more. Retro fitting can be done but not easy or as efficient. I dont think you can have drain back systems on unvented.
I wasnt very constructive was i

 

[Paul Barker]

Only thing you can do now is buy another unvented cylinder and put that one on ebay.

 

[BigBurner]

Only thing you can do now is buy another unvented cylinder and put that one on ebay.

if the immersion is at the bottom, he can have a coil fitted that is heated via solar panels.

 

[dornfield]

I wondered about that. There are two ports for immersion heaters, one at the bottom and one mid-tank. So the idea of using electric power to "take the chill off the water" and then gas to then heat it to temperature (using less gas) would be attractive. Would this be a specialist firm that would do this sort of installation? I don't tend to touch electrics since my brother-in-law, who is an electronic engineer, refused to help me reqire my house because he doesn't do 240V...."that stuff will kill you....", I clearly remember hiom saying!

Thanks for help thusfar.

Brian

 

[Paul Barker]

Nice idea however the immersions on unvented cylinder are not the standard 2 1/4 thread of the vented copper cylinder. If a coil is available all well and good.

If you have space buy a second single coil cylinder for the solar set the stat on the existing cylinder to alttle under 43 degrees put a tmv on the solar cylinder set a littleover 43 degrees and pass the output of the solar to the input of the existing. Then whenever solar is above 43 you only use solar (except for losses). When it is under you are only toping it up with hydrocarbons when it is very high you are not endangering the second cylinder to the level which would bring the tpr valve into play by use of the tmv.

With me?

 

[Norcon]

Paul Barker wrote

set the stat on the existing cylinder to alttle under 43

Sorry to butt in but isn't 43 a little low ?.
Legionella, getting the un eaten valuable food of the dinner plates etc.
Always keep mine set at 60.

 

[BigBurner]

Nice idea however the immersions on unvented cylinder are not the standard 2 1/4 thread of the vented copper cylinder. If a coil is available all well and good.

If you have space buy a second single coil cylinder for the solar set the stat on the existing cylinder to alttle under 43 degrees put a tmv on the solar cylinder set a littleover 43 degrees and pass the output of the solar to the input of the existing. Then whenever solar is above 43 you only use solar (except for losses). When it is under you are only toping it up with hydrocarbons when it is very high you are not endangering the second cylinder to the level which would bring the tpr valve into play by use of the tmv.

With me?

If the temp inside the solar cylinder is above say 55C then that is used as it is free. Best have no TMV on the solar preheat and one on the main cylinder set to say 50-55C, as if the temp inside is over 55C it doesn't matter. TMVs will be standard soon, so the trade press keep saying.

 

[Paul Barker]

you guys are right about legionella 50 degree is sufficient.

But only to meet the scaremonger nanny state requirements.

The reality of legionella is different to the scare.