Heating switching on and off, cold radiators, magnaclean?

[jamescycling1]

British Gas replaced the heat exchanger as it was leaking. I have a glowworm swiftboiler.
Now my heating is back working but not 100%. When I put the heating on I can see the flame (through the window in the boiler) go on for about ten seconds then switch off, go on then off etc. Some of the radiators are very slow to heat up, and are not hot all over, and other radiators get hot straight away and stay hot. British Gas has recommended a course of Magnaclean for £256 - will this make a difference, and is there anything else I can do?

 

[twgas]

sounds like either a temp sensor or circulation problem, if circulation could be pump, or blockage - magnaclean may help

 

[simond]

If it has got to the point of a partial blockage then Magnaclean is just a filter, it won't make a significant difference.

You need a water test analysis and probably that will lead to a Powerflush.

By all means fit a Magnaclean once you have done that!

 

[gas4you]

I am of the opinion that whenever a new HE is fitted to any boiler the system should be flushed immediately, otherwise you could be invalidating any warranty on the new HE.

After all what is the difference in fitting a new boiler and flushing out and fitting a new HE?

The flush on either is to protect the new HE.

£256 for a Magnaclean to be fitted Is that the solid gold version

Agree with Simon, a magnaclean is not designed to solve this problem, but just to help keep a system clean after a proper flush and cleanse has been carried out.