HIU issue and possible leak

[eagleeye]

Hi guys hopefully you can help me here. I went to a property yesterday for a problem with no heating. Found that they had a HIU for hot water and heating and narrowed the problem down to the motorized valve. My question is though does anyone know what would cause all the foaming and crud around the joints and pipework ? I understand it could be a leak from the seals but never seen this happen before

 

[ShaunCorbs]

I would say the joints have been leaking and are you in a hard water area?

 

[oz-plumber]

As above or someone has dosed the system with the wrong chemicals or put leak sealer in the system

 

[Chuck]

It looks like several joints have been leaking independently with the hotest ones affected worst. I suspect that if you dismantle all the joints that have been leaking they will have the same type of brass olive. My guess, incompatible additive or something acidic (flux or cleaner) not properly flushed out of the system. Could be manufacturing fault but much less likely in my opinion.