Primary Heat exchanger Scaled Up? Vaillant vcw 242 EH

[trelo]

Hi
My radiators are noticeably not as hot as they were.
I observed the boiler for about 5 or 10 minutes whilst holding the flow and return pipes.
The burner fires up and the flow pipe would get hot as expected and then the burner would cut out completely after maybe a minute or 2...(not modulating down) the water pump would continue running for a further few minutes and you can feel the pipes equalize in temperature. The burner would cut back in and this process would repeat but never getting so hot where you would take your hand away as you would expect.

I also can hear a sound building up during the 'heating up' stage described above. Not sure if this is just normal or a sign of kettling? The heat exchanger (primary) was replaced when I moved in to the house 18 years ago because it was furred up then. But the sound it made then was horrendous. It was heating up and started banging like a fire cracker! (well, not quite that bad...but similar crackling sound)

Do you reckon its scale build up now?

Could it be the water pump failing?

Many thanks

 

[John506]

The heat exchanger was replaced 18 years ago? How old is the boiler?

 

[Agile]

How many times has the boiler been serviced?

How long ago was the last time?

Tony

 

[trelo]

Sorry. Havn't been back to see answers because my email client not posting replys!

I have been offered a new boiler and was wondering if it would be a suitable replacement for this one. Its a Remeha combi 39c here is the spec on it: http://www.remehaheating.co.uk/installer/products/combi-boilers/technical-specifications/

The price is £1000

Should I have the system power flushed also?

My 242 was serviced about 18 months ago and the age is about 25 years. but I'm now thinking of replacing it. I've had a good run with it and it would be sad to see it go but new boilers seem so much more efficient now and I believe the parts on the 242 are becoming scarcer now.

Thanks