HVAC Questions? Ask an HVAC Expert for Answers ASAP
Hello, I'm unclear about the use of detergent in the system - are you sure it was detergent? And for how long was the chemical in the system?Also, is your magnetic filter installed on the flow from the boiler, or on the return?
S.53 indicates a blockage, not always, but the non-ventable rads support this theory.IMHO using F3 (or similar) for only a day, on a system that already has a suspected blockage, won't achieve anything.Is your system open-vented or sealed?
That depends on the position and nature of the blockage. I'm curious about the age and history of your system, but putting that aside for now I would aim straight for the most common problem area, which is the connection of the cold feed (from the F&E cistern) into the primary circuit. This involves draining, pipe cutting, probably some mess, and some mechanical clearing.Other problem areas are the ports of the circulating pump, and any motorised valve.There will be a delay of about an hour before I can reply again. Hopefully this is food for thought for now. If you want chapter and verse my experiences of problems like this, it would be best done on the phone. I could do that either late tonight or early tomorrow. Otherwise I will keep replying in here when I can. If you're not confident in doing this yourself, then I would ditch your plumber and find a decent heating engineer.