help 2 cold radiators :(

[ALGORYTHM]

hello all, my first post and what a great resource this site is. hope somebody can provide some answers for me.

first of all i have 2 cold radiators on the first floor, i don't think its a pump problem as the 2nd floor radiators are fine. we recently had a new hot water cylinder fitted and all the radiators worked fine. hot water was messed up so the plumber came back and drained the system down (turned off all the radiators) and cleaned out the sludge in the system.

when we tried the system before he left we only tested the ground floor radiators which worked. a week later and i've just realised the problem with the first floor pair. i've tried turning them on and off and bleeding them but no luck.

here's the valve i use to turn it on and off:

http://algorythm.co.uk/pics/3ALB0006.jpg

and there's this one at the other end:

http://algorythm.co.uk/pics/3ALB0004.jpg
http://algorythm.co.uk/pics/3ALB0005.jpg

i don't know what it does but i have a feeling the plumber did something with a wrench any ideas please as you've probably guessed i've no technical knowledge for this sort of thing, prefer computers.

thanks in advance!

 

[masona]

What happen when you bleed the radiator? water,air or nothing?

Do this with the pump off.

 

[ALGORYTHM]

water with both the pump on and off.

 

[sifu]

Try this:
turn on 'heating only' at the timer (if possible);
shut all other rads bar just one of the faulty ones;
make sure both rad valves on the faulty rad are fully open;
turn the pump to max speed if not already;
close the bypass if you have one and you know what it is;
do the same with the other rad.

If this doesn't work, then crack open the joint on the rad valve where it goes into the rad and open up the valve into a bucket/tray to check for air/blockages, try this at both ends of the rad. If no air/water comes out of the pipe then you probably have sludge.

 

[ALGORYTHM]

thanks for the reply, here's what i tried:

1. cant turn heating only on, water and heating.

2. turned off the ones that worked.

3. both rad valves? i can only turn one, opened it fully though

4. pump is always max

5. dont know what a bypass is, description might help me.

this hasn't worked so far. i'm not about to open a valve, as i'm guessing i'll have to turn off all the water, heating etc then when i restore it i'm pretty sure i'll have an airlock.

when the new hot water cylinder was fitted it didn't work due to the sludge, the rads worked fine though now it's the other way round, after the sludge was cleaned out is sludge the most likely option considering we just had the system flushed? if so i'll get the plumber back here and tell him he didn't flush it well enough

 

[oilman]

He may not have flushed it properly, but tread carefully. When you flush a system it loosens a lot of rubbish, and this may come out while flushing, it may not move till later. It makes a big difference if the system is drained, so you flush till it looks clean, then drain. This can be surprising with the amount of debris that comes out.

The thing is, a problem with an old system when it's flushed, is that it's still an old system that wasn't looked after over the years. So whilst you're putting your point of view..............

It can take weeks for air to move round a system so it can be bled, and it can take ages for debris to move as well. A dedicated, patient approach is needed.