I have a Saunier Duval 80ff.When the system fires up knocking noise starts for about 2 minutes then recedes.When it turns off same thing happens.Was told it was the fan replaced the fan no change.the boiler is 3 years old.But the pipe work is about 25 years old.Have drained down several times and bled the system.the noise is getting louder now.Any advice appreciated.the engineer put a metal bar from the fan to his ear and stated it was the fan.
Knocking Boiler
- Thread starter Baz77
- Start date
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pump ? 
yes its normal try a screwdriver on the pump and see if you can hear the noise
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check the pipework isnt touching anywhere could well be the problem
Kevplumb.
Thanks my friend for your assistance.The boiler as been fine for over 2 years.the pipework as not been touched at all.When you place a screwdriver on the heat exchanger you hear a faint tapping,but when you place it on the fan assemlby it is very loud as this is a new fan and the old one did the same i cannot see that being at fault.It sounds like something is expanding when it fires up then retracts as it switches off.many thanks once again.
Thanks my friend for your assistance.The boiler as been fine for over 2 years.the pipework as not been touched at all.When you place a screwdriver on the heat exchanger you hear a faint tapping,but when you place it on the fan assemlby it is very loud as this is a new fan and the old one did the same i cannot see that being at fault.It sounds like something is expanding when it fires up then retracts as it switches off.many thanks once again.
still says pipework to me
kevplumb.
I have been reading the installation notes and assembly instructions for the boiler.And between the heat exchanger and the fan unit there is a gasket.would you say that the gasket would reduce the tapping from the boiler to the fan unit.But this is the opposite the noise from the fan is much louder.I would think that the gasket would act as a baffle between boiler and fan unit.Your information is certainly appreciated.Any ideas if the pipework is o.k.
I have been reading the installation notes and assembly instructions for the boiler.And between the heat exchanger and the fan unit there is a gasket.would you say that the gasket would reduce the tapping from the boiler to the fan unit.But this is the opposite the noise from the fan is much louder.I would think that the gasket would act as a baffle between boiler and fan unit.Your information is certainly appreciated.Any ideas if the pipework is o.k.
could try changing the gasket
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