We had a Worcester-Bosch Greenstar 30CDi boiler installed about six
months ago. It is working generally fine but I've noticed that about
every couple of weeks the last radiator in the system makes slight
gurgling noises and needs to be 'bled' to let out some air. As a
consequence of doing this ( I presume), the boiler's water pressure
drops slightly because I then have to readjust it back to its normal one
Bar level.

Is a pressure drop with time something to be expected of a system such
as ours or is the air that gets into the radiator an indication that
there may be a leak in the system somewhere? Should I be concerned and,
if so, what is the best course of action for me to take?

Before the boiler was commissioned the installer filled the entire
heating system with a chemical which was left overnight and then flushed
out the next day until the water coming out was completely clean.

The central heating pipework in this house is at least 40 years old so
I'm wondering if this treatment could have caused pinholes to develop in
one or more of the joints. Since the leak, if there is one, is so slight
(at the moment), I'm inclined to do nothing at the moment except to keep
an eye on the system, but I'd really appreciate hearing any comments
from the experts in this NG.

Many thanks, and a Happy New Year to all.

TIA - Dave.

--
David C.Chapman - )
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