been up the loft today no dead legs, but has been changed from open vented, most hot water pipe still in 22mm up and down and round the house. then the penny dropped..:lightbulb: ..although I had drained and refilled the system, tested for leaks and had the water running in the new bathroom, it is still not in proper use.
so opened the hot taps on full, seemed ok but then some periodic spluttering as air was getting forced out.
flow was still not very good, went back in loft and found a cheap iso valve on the 15mm up from the boiler, removed that then a lot easier to force the air through the pipe.
:frown2:..problem caused and cured.. "still a rookie"..:disappointed:
Now you know what causes the issue though Simon and what to look for to cure it 🙂 We are forever learning, that's what I like about this forum! Folk here more than willing to share their experiences! Glad to know you got to the bottom of the problem and all is now as it should be 🙂
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Reply to the thread, titled "opening cold tap has effect on boiler" which is posted in Boiler Advice Forum on Plumbers Forums.