I have a Worcester system boiler about 6 years old and I can hear a gurgling coming from it. This has not always happened. It is a condensing boiler, but not a combi. Pressure is about 1.75 bar and doesn't drop. None of the radiators have air in them including a towel rail in the bathroom directly above the boiler which was installed as a bypass. It is a modulating boiler and I have the boiler control On 3 out of 5, the noise seems to stop if I turn the boiler up to 5 or Max. It hasn't had a service for 2years. Apart from the noise it is working fine. Is this noise something to worry about?
Thanks in advance.
Thanks in advance.