Solar panel/shower pump

[Fatboise]

I have recently moved into my new house and need to install a shower

pump on my gravity fed system. I also have a solar panel attached t the roof which will be plumbed through the HW cylinder to provide ho water (not operational yet).

The problem that I think I may have is that the temperature of th water in the cylinder cannot be regulated when the solar panel i operating and it may rise over 65 celcius on a hot day. The only thin that I can think of doing is adding a thermostat that would shut of the water supply/power to protect the pump but then nobody can have shower until the water temp goes dowm!!! Does anybody have an suggestions how I could runthe pump if the above sutuation occours??

Thanking you in advance............

-- Fatboise

[John Rumm]

Fairy snuff...

I am a bit confused about which pump you are talking about since you will probably two independent and unconnected ones.

The shower pump will be a twin impeller high pressure jobbie that will feed the shower from the cylinder and a suitable cold water supply, but have nothing to do with the solar panel.

The solar panel will need a circulation pump plus some form of differential thermostat. This pump will pump the solar heating system water round the/a heat exchanger in the cylinder and have no direct connection to the water that is being heated in the cylinder.

The solar pump would be controlled from a differential stat such that it only run when (a) the water in the tank colder than the set point temp, and b) when the water available from the solar panel is hotter than the tank water. (A) takes care of the water in the cylinder not getting too hot, and (B) stops all the heat accumulated in the tank from being pumped back outside again as soon as the sun goes in!

You may also need a anti convection valve in there as well to stop any gravity circulation.

[Alan]

You should get a tempering valve - it adds cold water to the hot water feed so that it is never scalding hot.

Alan.

[meow2222]

Hang on. I'll take a guess the panel was there when you mvoed in. If so...

First the solar panel will put out lukewarm water unless you pump it very slowly. These are not fast devices. Also most are not freeze proof, and require a separate antifreeze circuit. Many home made ones are direct heat and need draining down in winter. A few are freeze proof and can be run direct with no extra issues.

How to plumb it depends on the type of panel, and to some extent the type of HW setup. But I would not simply assume that pumping tank HW through it is necessarily the right thing. We'd need more info, eg what size is it, is this a small commercial panel or a big home made job, etc

If its a big panel, yes. Not going to happen with commercial panels. Even if it does, its not much of a problem.

that doesnt seem to make sense.

it wont. Not unless someone's gone solar crazy and installed 10m2 of high efficiency home made panels. It has been known, but is rare.

NT