Help with hot water please

Just moved into a new house built 2008 and it has a solar water heater on the roof plus a cylinder in the house which looks like any other I've seen.

There is no instructions on the solar one.

Can anyone please explain how they work, do they feed the cylinder?

Picture of cylinder below.


Thanks in advance.

It's certainly possible to combine a solar heater with a cylinder but it's difficult to divine what you've got from a picture of the cylinder.

The two taps below are a curiosity though and it may be that they are there as some sort of manual switchover from one to the other.

I arranged something similar in my previous property in France which had an oil boiler for heating and hot water but the HW side was very small which meant firing up the boiler twice a day to ensure there was HW (well warm anyway) throughout the day.

I fitted a 200lt cylinder then through a tap tee'd the hot from it into the supply to the house and fitted another similar tap in the hot feed from tbe boiler.

By closing that and opening the tap on the cylinder the HW was supplied from that while the opposite way meant that it was from the boiler although in fact I never used it that way again because the arrangement not only halved my annual oil consumption saving me about €750 per annum but also reduced wear and tear on the boiler which then only needed to be fired up for the central heating in Winter.

Electricity was cheap and it was costing me just around €10/mth for what was in effect virtually unlimited HW.

Substitute solar for boiler in that scenario and it might be what you have.

A.N.Other wrote:It's certainly possible to combine a solar heater with a cylinder but it's difficult to divine what you've got from a picture of the cylinder.

The two taps below are a curiosity though and it may be that they are there as some sort of manual switchover from one to the other.

I arranged something similar in my previous property in France which had an oil boiler for heating and hot water but the HW side was very small which meant firing up the boiler twice a day to ensure there was HW (well warm anyway) throughout the day.

I fitted a 200lt cylinder then through a tap tee'd the hot from it into the supply to the house and fitted another similar tap in the hot feed from tbe boiler.

By closing that and opening the tap on the cylinder the HW was supplied from that while the opposite way meant that it was from the boiler although in fact I never used it that way again because the arrangement not only halved my annual oil consumption saving me about €750 per annum but also reduced wear and tear on the boiler which then only needed to be fired up for the central heating in Winter.

Electricity was cheap and it was costing me just around €10/mth for what was in effect virtually unlimited HW.


Substitute solar for boiler in that scenario and it might be what you have.

Do you think the solar heater has been done away with as it seems to have a cold feed? a hot coming out? and a clear drain for emptying?

Normally the solar panels would provide an electric supply to the immersion heater element. They heat the water in the tank until it reaches the thermostat setting. Simples.

Sage wrote:Normally the solar panels would provide an electric supply to the immersion heater element. They heat the water in the tank until it reaches the thermostat setting. Simples.

That's what I assumed but one tank on roof with panel and one electric tank inside. Perhaps one takes over if not enough sun but no sign of a way to say which to use.

Is the panel on the roof a glass pipe array that heats the water in the pipes and feeds the cylinder attached

jpeg wrote:Is the panel on the roof a glass pipe array that heats the water in the pipes and feeds the cylinder attached

not sure, can't really see, photo below

What you appear to have is a Thermosyphon System. The rooftop tank and solar panel is connected to the water supply. So the cold water pressure feeds the rooftop tank. The solar panel heats the water on the roof. When you turn on the hot tap in the kitchen or bathroom, gravity feeds the hot water from the roof to the tap. Hope that description helps.

If you want to check if it's working.....switch off the immersion heater completely. Wait until we have a very sunny day, turn on a hot tap, if it's hot the heat is being supplied by the rooftop solar system.

Sage wrote:What you appear to have is a Thermosyphon System. The rooftop tank and solar panel is connected to the water supply. So the cold water pressure feeds the rooftop tank. The solar panel heats the water on the roof. When you turn on the hot tap in the kitchen or bathroom, gravity feeds the hot water from the roof to the tap. Hope that description helps.


If you want to check if it's working.....switch off the immersion heater completely. Wait until we have a very sunny day, turn on a hot tap, if it's hot the heat is being supplied by the rooftop solar system.

perfect, will do

I could maybe come and have a look for you and see if we could sort it out. I have a similar system. No charge.