Noisy Central Heating

The Grundfos pump on my Baxi Combi 80e boiler continued to be noisy despite opening the screw on the automatic air vent when refilling the system. I loosened the large silver bleed screw on the pump while the heating was running which released trapped air and reduced the vibration. The noise was completely deadened by jamming a piece of foam behind the cold water supply pipe.

There was also "kettleing" noise from the boiler's heat exchanger just before it cut out after refilling the system, despite adding Sentinel X100 corrosion inhibitor. The noise disappeared completely after a month presumably after dissolved air had been removed from the water.

I sometimes get some trapped air (that's in the C/H system you understand), what I do is to 'pulse' the system by turning the C/H pump on to the high speed for say 20 seconds and then shut it off for 20 seconds to allow the air to rise up to the header tank. I do this a couple of times and that's that. Obviously I check the rads for air too and bleed that out.

Chris.

I can't see any questions, so I guess this was a "tip".

The noise above is caused by a loose washer in the ball-valve.

The air noise can be cured with some Fairy Liquid in the header tank.

How much do you recommend? One bottle, or two? :-D

john

About an egg cup full.