Radiators cold a bottom + use of sentinel x800

[taz8520]

Hi all ,my mum had a new ideal boiler fitted about 6 years ago, she had quite a few problems with it since installed, one of which was a new heat exchange fitted, any way they supposedly flushed the system when installing it :/ but now most of the rads are warm at top and cold at bottom which I am guess will be down to a build up of sludge over the years?, as she hasn't got the funds for a powerflush which BG recommend, I was thinking of taking all the rads off ( 8 of them ) and flush them though with a hose or even jet washer when the weather gets a bit warmer, would that likely fix the problem ? Also can I put some sentinel x800 in the system and leave it for a week or however long would be best prior to cleaning the rads?

Many thanks Steve

 

[plumber0808]

Add a good cleaner in it and leave it for a week yes.
it is also a good idea to take them off and manually flush them out.

if its that bad, it can line the pipework reducing its diameter.

 

[plumber0808]

Just re read the post. Not many people have got the funds to afford to pay for a BG powerflush.
get a local recommended plumber to give you a realistic price for a powerflush

 

[bewsh]

I wouldn't leave X800 in for very long mind or it'll just eat away at your radiators. I'd go with X400 as it's not as aggressive. But ye, getting a hose pipe and forcing mains water through will sort the problem out.

 

[taz8520]

I did have a look at some prices some plumbers are offering and they even seem a bit to pricey at the mo :/, it wont hurt the try my diy effort first will it ? then if still has problems I will look a powerflush.

Is a week about the max time to leave sentinel x400 cleaner in the system ?

 

[bewsh]

Ye you can leave X400 in the system for a few weeks, so it'll be ok for what you need.

 

[taz8520]

That's great I will do that thanks , oh and also the combi boiler when the heat setting is turned up from about 3 to 4/5 it starts to knock, would this mostly likely be down to sludge build up or the water getting to hot inside the boiler ?