Could incorrect settings on solar controller cause constant pressure loss

[cathyr456]

Good afternoon,

I have solar panels installed on the roof, and noticed that the collector temp has been set to 124 degrees! The max recommended setting is 75 degrees. The minimum return temp has been set to -9. Could this be anything to do with why I have no pressure on the solar gauge. It has been topped up numerous times, but the engineers can find no leaks?

Could having this set so high have any other unwanted effects, or have an impact on efficiency.


Any comments would be appreciated!

[Kenneth199]

Is the expansion tank working correctly?

[Brian_UK]

If you keep topping up then it has a leak but also check the pressure relief catch tank to see if it has been overpressured.

[cathyr456]

Hi Brian and Ken,

I did do some research before I posted and came to the same conclusions as you both ie its either a leak, or the expansion vessel.

The engineers cannot find a leak. So how would I check if the expansion vessel is working correctly? (it is a 12 litre vessel, pre charged to 2.5 bar) and connected to a daikin altherma LT system

Thanks

Is this the same as the 'pressure relief catch tank'?

[Kenneth199]

2.5 bar sounds like precharged from factory.
I'm not 100% sure how to calculate the pressure.
I Cant find the formula at the moment. I think it is something with lifting height + 0.1 bar.

Example expansion vessel is installed before the pump in the basement, and there is 6m to the top of pipes. 1 bar = 10m so 6m = 0.6 bar + 0.1.
So the air pressure charge should be 0.7 bars.

Can someone please correct me if im wrong?


Does the pressure dissapear when the system temperature drops?
Where is the expansion vessel mounted?
What's the pressure before and after the pump?
Have you tried to start the system with cold water and see if the pressure raises with the temperature?

[nike123]

Constant pressure loss is due to evaporation of water at high temperatures through automatic air vents. You should install (if not already installed) special air vents for solar systems with ball valve before air vent. That valve should be closed in normal operation and open only when you venting air for some reason (like change of solar fluid and topping up after fixing leaks).

http://www.caleffi.com/usa/en-us/cat...r-vent-250041a
http://www.caleffi.com/usa/en-us/cat...r-vent-na29284

[nike123]

Can someone please correct me if im wrong?

http://www.reflex-pro.de/solaranlage.aspx