Rusting solar expansion vessel

Kev the gas · Oct 28, 2013

Hi all,

I popped into see a job today with a problematic solar system.

12 evacuated tubes

Twin coil cylinder in the loft, along with pump station and expansion vessel.

System not circulating but pump running, I checked the expansion vessel and saw it was badly corroded and leaking Goooo!!

Pressure gauge reading 2 bar but I think it is stuck, the sight glass for flow rate was mucky.

Obviously the leak has caused air in the system which is only 3 years old, the expansion vessel has already been replaced because it was leaking.

I presume the system was not cleaned out before final commissioning and the flux is now corroding the system ??

from my course @ Worcester 2 years ago I'm sure they said a there is a minimum head for Evacuated Tubes??

Can anyone confirm?? or dismiss my theory:2guns:

The customer is 85 years old and a little fed up after spending £7000 3 years ago.

The system was installed by So Solar of Southampton

Kev

Nostrum · Oct 28, 2013

Soldered joints are a no no so system shouldn't need flushing?

Heat at damage maybe? Or has the wrong type of expansion vessel been fitted or in the wrong orientation?

tamz · Oct 28, 2013

Probably could do with a protection vessel (another one filled with glycol) fitted before the expansion vessel.
Have a read of this
http://www.swithenbanks.co.uk/product_uploads/12325824131.pdf

Kev the gas · Oct 28, 2013

Thank you for replying Nostrum,

Exactly why I mentioned the soldered joints, I have only fitted 3 systems and have used the flexible coils and compression where I had to.

The expansion vessel is fitted at an angle to the roof joists using straps !!

The expansion vessel is correct for use in Solar installations. ( it says so on the sticker!)

Kev the gas · Oct 28, 2013

Thx Tamz,

you just woke up my sleepy brain !

Above is a pic of my last install, East/West split with Cooling vessels, from the roof down to the garage not a single joint using the coils, then using compression only at the pump stations.

I think I got a bit too involved with their bad luck story to think properly, I have just had a message from them nd they want it all removed and a new boiler installed.

Kev.