hot at top / cold at bottom / slow to heat rads

[snadge]

ive recently noticed that the dining room rad is slow to heat up and sometimes doesnt? - the living room one (next in line) is hot on top and warm/cold on bottom... when i drained system a few times when plumbing in wall mounted rad I noticed some of the water would have black/grey color to it... im reckoning this is sludge in the system and it needs cleaning and sorting...luckily ive found a draining valve on the hall rad next to back door

cany anyone offer advice on how to go about this and offer any advice?

thanks

 

[someonelse]

Most efficient way is a power flush. Ring a few plumbers for quotes, but not till the current busy period is over!

Or turn off the feed to the attic tank (NOT the cold tank!) to control feed into the system, drain the entire system down, poor in some inhibitor, refill system, and hope for the best.

 

[snadge]

Most efficient way is a power flush. Ring a few plumbers for quotes, but not till the current busy period is over!

Or turn off the feed to the attic tank (NOT the cold tank!) to control feed into the system, drain the entire system down, poor in some inhibitor, refill system, and hope for the best.

I have a closed pressurized system, i have no problems in doing this myself, ive practically re-built and re-plumbed the entire kitchen so am capable, Im thinking of draining the system, taking the rads and thermostat valve off and flushing them outside , then putting them back on and fill the system and drain it again as a sort of flush...then enter the inhibitor through the top of the wall mounted towel rail and then refilling the system...

just thought I would ask for some pointers

I have a few problems with this boiler anyway and a plumber is coming on Thursday to do the hob - im gunna ask for a price to fix a leak out of an outlet on one of the boilers pipes - this outlet is fitted onto a nut (of sorts) just screws onto this brass valve, the nut/outlet needs replacing... at moment its dripping slowly when CH is off so we just have a tea towel under it too soak it up and change it daily... how much do you think that would/should cost?

another problem is a slow loss of pressure over 1-2 weeks, could be a leak under ground floor, we will be ripping up the floor-boards in living and dining room next year - anyway im gunna ask him to check out these two...

thanks for quick reply