Hot water solar panels

syboit

Hi,

Looking into getting solar panels. Just reading through some threads here and I see people mentioning "anti-scald valves" and "heat dump devices". Are these standard installs on all systems ?

Would you need to install anti-scald valves on each of the hot water taps in the house ?
Where would a heat dump usually go, is this just a standard radiator ?

quentingargan

Anti scald valves go on the outlet from the cylinder. They really should be there on all systems in case of a failure of some thermostat, or any other incident that caused water to get heated above 60 degrees. Generally with solar, it is considered best practice to use one.

If you have one, you can then heat the cylinder up to higher than 60 degrees and harvest extra energy on hot days. But don't do that if you have limescale in the water...

Heat dumps are there to take the heat from the solar panel after the cylinder is fully up to temperature. They are particularly advised for tube systems - there is a workaround for flatplates with some controllers by keeping the panel hot, but not boiling for a period of time to dissipate heat. Tubes are very well insulated, and if your cylinder is hot, and the pump is simply knocked off, the water in the system will boil and be sent to the expansion vessel. No harm in that, but it damages the antifreeze and puts a lot of pressure on fittings and pipe insulation close to the panel.

I prefer to see them used on all tube systems, but for cost reasons, they are usually left out, which is a shame.

shane0007

Anti-scald valves are a must on any domestic hot water solar installation. Any installer who installs a system without done is a disgrace. They are a basic safety system installed to ensure people are not scalded by extremely high water temperatures achieved by solar, and especially there to protect the young and the elderly who can be more affected by these high temperatures.
It will also increase the volume of available hot water within your cylinder, for example, a hot water tap drawing from a cylinder without one can draw say 5 litres per min. Say for 10 mins, that is 50 litres of hot water from the cylinder at the cylinder temperature. The same tap drawing from a cylinder with an anti-scald valve, will draw the same volume of water, 50 litres over 10 mins, however, depending on the cylinder temperature, a rate of 60/40 is generally applied so only 30 litres is drawn from the cylinder and is at the correct temperature to be used at.

rosepaddy

syboit wrote: »

Hi,

Looking into getting solar panels. Just reading through some threads here and I see people mentioning "anti-scald valves" and "heat dump devices". Are these standard installs on all systems ?

Would you need to install anti-scald valves on each of the hot water taps in the house ?
Where would a heat dump usually go, is this just a standard radiator ?

anti scald valve is to reduce very hot water leaving your cylinder indirectly increasing the capacity of your cylinder but also ensuring you dont get burnt from water at 60/70/80 degrees it is placed at the point of departure from the cylinder

tred

Was chatting to my plumbing supplier, they include the anti scald valves in all solar packages. Any lad that wouldnt be putting the scald valves, or even the dumps, id be wary of. Just make sure you include it in your spec.

rupio

I represent [snip]....

DOCARCH

@Rupio

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rupio

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