Kettling noise boiler help+ air in cylinder

[ih]

Hi For the past week 20 year old work horse boiler has started kettling noise ( medium pitch) boiler has had bi annual service and x100 topped up over 6 years ago when 3 port valve was replaced
1.Boiler potterton profile 100e 2.F&E tank 3.10 Radiators 4.HW storage cylinder with thermostat 5.fitted Water Softner 6.Twintech magnaclean (due to space constraint was fitted near the pump in loft cleaned annually) 7 boiler statis normally set 1.5 summer & between 3&4 in winter thanking in advance
Kindly note couple of days ago had air in hot water taps i had to drain the cylinder to get rid of the air
I had the same problems 6months ago!
Help/advise on kettling & air in hot water will be much appreciated
Ih

 

[Mike2007]

Boiler heat exchanger may be furred up due to age.

 

[JohnD]

air in hot water taps i had to drain the cylinder to get rid of the air
I had the same problems 6months ago!

That's odd.

Have you got a shower pump?

Is the cylinder fed from a cold water tank in the loft? Which has the greater capacity?

 

[ih]

Hi many thanks Mike &JohnD
Yes! Shower pump without any flanges could be the culprit few years ago when plumber replaced the shower pump
He said flange was not necessary! Fyi cws tank is 50 gallons and the cylinder is 140 ltr capacity since my initial post
I have drained the system added X200 & X100 ! (did this 5 days ago) the boiler is much Quiter so are couple of pipes
To the radiator which were little noisy when the heating came up! On refilling the ststem i managed to get air lock & with help
Of this website cleared it from the pump & radiators!
Ps cylinder is fed from the tank in the loft apart from boiler all in loft

 

[Mottie]

Had the exact same problem a few months ago with our Potterton profile 60e boiler. It’s a sealed system with an unvented hot water cylinder. As it was 25 years old and with winter coming up, I bit the bullet and had it changed for a modern boiler. All good so far!