In message .com,
writes
Hope someone can pinpoint this problem and suggest some solution/
advice. Our Central Heating system is making a loud whooshing sound at
start up. We think the gas boiler (8 yrs old) is drawing in air into
the hot water tank and this is the source of the noise.Is our diagnosis
right? How can we pinpoint the fault in the system? Thanks for all your
time. denise )

Is this something which has recently started, have you recently moved
in, etc ...

a clue as to what boiler it is might help

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geoff