I had this boiler fitted 5yrs ago and ran it at 75c for the first 3 yrs and it seemed ok. I then upped it to its max temp. 2 yrs ago and then noticed what I thought was cavitation which started at 70c and disappeared when it reached 82c and modulating. I have the programmer set on hot water only for the first hour 6am-7am, and then the rest of the day it runs heating only. The boiler has the same fault on both seperate circuits. I have had the system power flushed but to no avail. The installer has serviced this boiler annually, but the problem has got him baffled and he is now clutching at straws and wants to fit a new pcb but without a logical reason. I have checked boiler flow and return temps and there is a 20c drop until the temp. gets close to 82c. it then drops to about 10c diff. I was a heating fitter until I retired 20yrs ago. Any suggestions would be appreciated.
Glow-worm 12hxi problem.
- Thread starter john320d
- Start date
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Boilers don't cavitate, but pumps can. I would think your noise is heat exchanger related. Probably not doing any harm.
It is causing the nearest rad to need venting.
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Open vented or sealed system? If it's open there may be several reasons for air in rad?
Vented system.
Problem is, the system is quiet when running at top temp. on modulated flame.
Before getting up to target temp it will be running flat out so that's when you are most likely to hear kettling and associated noises. The heat exchanger may be becoming partially blocked so use of a system cleaner such as Fernox DS40 might help.
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