two cold rads (help please)

[mw]

It all started just before the summer when a small rad downstairs didn't heat up, I never got round to doing anything about it!. Turned on the central heating two weeks ago and again not heat to this rad nor a small rad up stairs? also another rad upstairs only gets warm at the top. I only have seven rads in my 2 bed semi, the ones that do work are very hot, which generally keeps the house warm.
the system is on 10mm micro bore pipes (Grey plastic).

I called a engineer to do a service to my boiler which he did, he also put a carton of X400 sludge remove in the feed tank in the loft (didn't drain the system) and said for me to wait to see if this frees up the rads as it maybe a sludge problem.

I get a funny feeling it wont work or is this just me??? does something else need to be done? Im no DIY expert but Im willing to try my hand with the aim of reducing the overall bill.

what about cleaning the rads individually?
draining the system?
power flush?

or just wait and see with this X400, it says it can take up to 4 weeks.

 

[corgiman]

Maybe sludge may not be

Firstly flush that 400 out after its been in 4 weeks any way

then try turning the rad vales on the radiators that are working as there may be a slight airlock in the 10mm pipe preventing the others heating up

BTW the system dont sound that old if its using 10mm grey (polyplumb, hep20 or similar) So doubt if it is sludge really

 

[mw]

would you recomend taking off the rads that are not heating up and flushing them out???

Also a rad upstairs is now only getting warn at the top and staying cold at the bottom?? should I flush this also.

when the plumber put the X400 in the tank he didnt take any water out the system, therefore will the X400 just stay in the water tank?????
Do I need to drain a rad to pull water from the tank in to my system???? to get the X400 to start working round my rads?

 

[corgiman]

I do recommend that you isolate the rads and whack a hose pipe on them, in the garden mind as doing in the house tends to upset the missus

and again if the muppet did not remove any water from the system then that luvvery sentinel is just sitting in the f and e tank

drain off some water to get the stuff into the system let it doe its thing for a month the flush it out

 

[mw]

cheers corgiman for all your help mate, I'll do my best to get the rads off, im the worst DIY man in the world???