Max temp in tank, solar circuit not pumping.

1100010110

Can somebody enlighten me please before I contact architect, contractor, plumber & tank suppliers.
I popped back to house at 1pm today, sun was shining, had a quick look at the solar controller, reading 81 degrees C at the panel, and 58 degrees C at top of solar coil in the tank, but was not pumping.

Details of components
Accumulator tank = 600L Cordivari Eco Combi 3
Solar array = 6m2 of Thermomax HP400.
Solar controller = SC400

The heating and integration of different systems to glean as much energy as possible from available sources was something I had stressed over and reluctantly handed over to my architect at the time as I had pressure from different angles at the time, now I am worried that a token system has been installed.
Does anybody here have thoughts/opinions/knowledge of details/issue above and is it a matter of adjusting the controller to keep pumping?

1100010110

OK, reading through the controller install docs and it says that the max storage tank temp can be set up to 95 degrees celsius with a factory setting of 60 degrees celsius, looks like the plumber didn't adjust the factory default on the controller.

quentingargan

But be careful with those settings... If you have a lot of limescale in your water and you ask the system to bring the cylinder over about 60 degrees, you will soon have a lime encrusted cylinder which is ineffective at heat transfer.

Any solar water heating system will, sometimes, produce more energy than you need. We have our cylinder set to 80C, but sometimes the cylinder is up to temperature and there is surplus energy. If you are to have sufficient supplies of hot water in spring and autumn, there is likely to be a surplus on those occasional hot days.

1100010110

Checked the controller, the max temp setting for the tank at the moment is 65 degrees celsius.
Water supply is soft water so no great threat from limescale build up, heat dump strategy taken care of also so will look at increasing the max tank temp setting and see how we get on.

quentingargan

I wouldn't set it above 80 or 85. You may have other relief valves that blow at 90. Be aware also that there is a risk that the thermostat on your immersion might trip permanently (i.e. requiring a reset) if you go to such high temperatures.

1100010110

The maximum temperature setting for the top of the tank is 95 degrees celsius, at which point the heat dump strategy occurs.
The maximum temperature of the heat pipes at which heat transfer occurs into the manifold and subsequently through the solar coil is 110 degrees celsius before the snap disk on the pipes should activate and stop transfer, so (forgive the language) with pumping and dumping, if more energy is gained than can be used within those rare times when we get a decent spell of solar radiation, most of the energy harvested by the solar array should be transferred to the tank, which should be able to deal with it under normal usage and energy draws from it.

ccsolar

1100010110 wrote: »

The maximum temperature setting for the top of the tank is 95 degrees celsius, at which point the heat dump strategy occurs.
The maximum temperature of the heat pipes at which heat transfer occurs into the manifold and subsequently through the solar coil is 110 degrees celsius before the snap disk on the pipes should activate and stop transfer, so (forgive the language) with pumping and dumping, if more energy is gained than can be used within those rare times when we get a decent spell of solar radiation, most of the energy harvested by the solar array should be transferred to the tank, which should be able to deal with it under normal usage and energy draws from it.

Hi
Just wondering what your heat dump strategy is?
Have you an anti scald valve fitted?
What is the operating temp of the anti scald valve? ( will it work at such a high temp)
Cc

1100010110

Underfloor heating throughout, heat dump are 2 X large towel rads pumped when the top tank temperature exceeds 95degrees celsius, they can also be timed with a clock for same.
The tank is a 600 litre thermal store/accumulator tank, 503 litres of which is the actual storage volume.
The DHW is from a corrugated coil which flows through the tank, 31 litre volume, 5.3m2 surface area.
Anti scald valve is fitted, I'm not the plumber so not 100% what temperature it was set at or it's operating parameters, will have a look at lunch time to get the model no.

ccsolar

1100010110 wrote: »

Underfloor heating throughout, heat dump are 2 X large towel rads pumped when the top tank temperature exceeds 95degrees celsius, they can also be timed with a clock for same.
The tank is a 600 litre thermal store/accumulator tank, 503 litres of which is the actual storage volume.
The DHW is from a corrugated coil which flows through the tank, 31 litre volume, 5.3m2 surface area.
Anti scald valve is fitted, I'm not the plumber so not 100% what temperature it was set at or it's operating parameters, will have a look at lunch time to get the model no.

It's a fantastic set up, we install these tanks regularly, if you are going to increase the max temp do not go past 75 degrees as you could end up melting the pumping station.....
Also if the water is too hot the anti scald valve might not release it from the tank as most anti scald valves have a max temp also
Have you considered lowering the heat dump temp, ?

Cc

1100010110

Cc, thanks for your advice but I won't be going tinkering at the values myself, I'll leave that to the professionals, just a bit of an anxious new home owner.
I forgot to check the anti-scald valve details at lunch, was running and racing for the bank.
I have conacted my architect with my concerns and he is getting in touch with the system suppliers (tank, controls), to check what considerations need to be made re any changes to be applied to the solar controller maximum temperatures.