Solar Thermal settings

[dpmiller]

well 70 is already scalding temperature so you should be able to confirm a tempering valve on your hot tank? If so then yes, it's safe.

[Chriswills]

Ok thanks so I could turn it up to 80?

There is also a setting of OSYC on page 31 which is system cooling any idea what that is?

[Kai casswell]

Hi did you get this sorted? In my experience once it’s reached stagnation eg collector temp has risen so high the fluid has boiled, you need to wait till nighttime until it cools down again. If this is happening repeatedly everyday you may have a problem in the system. Each time the fluid boils and condenses it breaks down a little and will eventually sludge up the system. 
if you have a 300 litre cylinder and 3-5sqm of panels that is a good size for a family of 4-5 people but if you use less hot water it will overheat more often. 
the collector cooling and recooling functions can help but be very careful of letting the cylinder get to 95C especially as this is measured at the bottom of the cylinder  -  And so it will be even hotter at the top. 
Happy to help if you want to message me.  I’ve been working on solar thermal since 2007. Kai