blocked system?

[joe plumber]

hi all,
Got called to a job a few days ago to ballance some rads. i can get upstairs nice and hot however im struggling to get any warmth downstairs, which are all on drops from upstairs, the flow to therads is roasting hot however it is not returning. one icouldnt get any heat in at all not even the pipework! This led me to believe thesystem must be blocked? the system is ancient however the boiler has been recently updated along with trvs only. i drained the system and dosedwith de sludger left for a few days to circulate. On my return today i drained and fluished the system through however the problem still remains. would it be worth powerflushing? i have heard mixed opinions about them doing more damage than good. and i also have llimited experiance using them! any help and advice would be greatly apprecited.

thanks joe.

 

[macplumb]

What type of system is it? Have you tried turning the pump up a notch to see if that's ok it might be getting lazy. Or could be water running around hot water circuit to fast. Maybe airlocked.

 

[WHPES]

If the boile has been updated recently the system should already have been flushed.

Sounds most likely to be an airlock. Shut off the supply to the water cylinder and close all rad valves other than one of the cold ones, whack the pump on setting 3 and see if it sorts itself out (you will hear air gurgling round). Repeat for all the other cold rads then put everything back as it was.

 

[dontknowitall]

Is the pump working? Classic sympton of a failed circulating pump as hot water rises (therefore warming upstairs radiators).

 

[moogwai]

i had a job the other day which sounds the same.....i cut out the neutral point where the cold feed from the f & e tank meets up with the system and this was 90% blocked up....just enough water was trickling through to heat upstairs but downstairs there was nothing.....cleaned out blockage,replaced pipework and wehey there was heat all round the house!!! it was quite a big system too with 14 rads on.

 

[Billy Bob Bob]

Is the pump working? Classic sympton of a failed circulating pump as hot water rises (therefore warming upstairs radiators).

totally agree sounds like a knackerd pump

 

[JSPM]

Hi there.
Had a similar problem last month myself. Despite a recent "aparent flush" by British Gas home care scheme there was still an awful lot of sludge in the downstairs rads and pipe work, not to mention a blocked boiler feed pipe!!
I ended up replacing the feed pipe and feed/expansion tank.
To solve the cold rad issues I took off each cold rad, flushed with a hose or cold water, ran heating water through the rad valves into a bucket and replace and refilled the rad. I did this with each rad in turn and now works a treat.
A huge amount of black sludge and air came out.
Hope that helps. Good luck.

 

[Winston]

I had this yesterday put a new towel rad in to replace old rad, thought was a air lock Muck in the system took me ages to find the blockage just glad I put some cleaner in. God I hate microbore

 

[GavinSmith77]

try turning all the rads off except one downstairs you should get heat if both valves are open then open another and shut that one it should push the air through

 

[payney1974]

Is the pump working? Classic sympton of a failed circulating pump as hot water rises (therefore warming upstairs radiators).

i had a job the other day which sounds the same.....i cut out the neutral point where the cold feed from the f & e tank meets up with the system and this was 90% blocked up....just enough water was trickling through to heat upstairs but downstairs there was nothing.....cleaned out blockage,replaced pipework and wehey there was heat all round the house!!! it was quite a big system too with 14 rads on.

One of the above^^^^^^^^^^