I have a Worcester Bosch Highflow 400 boiler. The hot water works fine, the problem is the central heating. The pressure gauge keeps rising. I have changed the fill pipe from the mains, no leakage from mains side. When changing pipe, I noticed air bubbles coming from the central heating side. Any ideas, I have plummber coming in Friday. Many thanks for any advice.
your water to water heat exchange is more than likely got a small hole in it
thus it lets mains water into your system try eazy parts or let your plumber do it lol
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