Chaffoteaux & Maury Boiler Problems

[dgr302]

Hi all,
I have an old Chaffoteaux & Maury combi boiler with which im having 2 problems with. I would appreciate any help with either of them.

1. When I turn on my hot water, the boiler fires up ok but the water doesnt get hot unless i reduce the flow through the tap to a trickle. Once the water is hot I can then gradually start to increase the flow and the water remains hot, but if I increase it too much too quickly it goes cold again. Any Ideas?
I dont get this problem If my CH is running when I ask for HW, I get it piping hot water no matter what the flow is through the tap.

2. If I have my CH on then ask for HW I get an awful screeching noise coming from the boiler until I turn off the tap. I dont get this noise at any other time i.e. if my CH is on only or if the HW is on only. Any Ideas?

Hope someone can help

cheers.

 

[kevplumb]

model ????????

 

[dgr302]

its a celtic rsc 2.20

Hope that helps!

 

[kevplumb]

prob the diaphram in the diverter valve streched

 

[dgr302]

would that be the cause of both problems?

 

[kevplumb]

wouldnt suprise me

btw c&m call it a change over valve

if your handy you can get a service kit and strip the full valve

 

[dgr302]

Thanks for the advice

where would I be able to get a service kit from? I assume it would come with full instructions of what I need to do?

 

[kevplumb]

http://www.partscenter.co.uk/hrpc/default.html

 

[dgr302]

just read another post somewhere else on the forum and someone was having the identical problem to me(having to run taps at a trickle to get the water hot).
The reply was that this could be caused by sludge in the heat exchanger, could this also be the case for me? If so, how do you go about desludging a heat exchanger?