I have an open vented S plan heating system with a hot water cylinder. I drained the system added Fernox F3 cleaner to the expansion tank ( NOT the cold water storage tank) Then the system would not fill from the expansion tank so i back filled it from the rads.
All seemed fine
BUT now my HOT WATER is BLUE !!!!!?????
Any ideas what's gone wrong and what i can do to fix it???
Put some old copper pipe into some fernox F3 in boiling water and it turned the same clear Mediterranean blue!! Proving i think that the F/E is feeding the hot water cylinder. Is this normal ?
It could be that the coil in your cylinder has pinholed/blown which means a new one!
I think you need a plumber in - ask friends/family for a reccomendation not an emergency one off yell etc.
Back filling with mains cold water may have damaged the heating coil in the cylinder especially if it old and in a poor condition - this will cause the DHW and heating water to mix.
Thanks for your last post and yes did seek proffesional help - 3 different ones in fact. Two refused to touch the system as it's a legacy system and has been modified many times ( it's a large old house)
A central heating engineer and his electrician have been and replaced the motorised valves and acctuators in the system and supposedly all are working. This plumber too had to backfill the sytem as it just wouldn't feed from the f/e. However i now have a lot of air in the system and the upstairs rads will not circulate correctly. The plumber would not work any longer on this and has told me to sort it myself and ring him in a couple of days!!
This latest guy has suggested, as you did that the pipe through the cylinder may have burst - this was a custom made cylinder 5 years ago would that happen so quickly? However he can't understand that if this is the case why i am getting perfectly clean water out of the cylinder and not dirty rad water.
I still have a sneaky suspision that my cold water tank is feeding my central heating n my f/e is doing who knows what.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!