Rads Not Getting Hot

[beefcake01uk]

Iv replaced the rad in the bathroom, but i had to change a bit of the pipe work so i drained the system down. Now when i turn the central heating on non of the rads get warm in the house. Any help please?

The system is a very old one, the boiler is really old two. Its NOT a one pipe system, i cant turn the central heating on without the hot water coming on as well. I have both CWSC and a F&E both with vent pipes.

On refilling i just turned the mains water back on, iam i right i thinking i need to bleed all the rads? If so is there any other tool for doing the job as iv not got a key for the rads, and the 1 i got with the new rad was a plastic one and its snapped!

Thanks for any replys

 

[bunny78]

in most cases you will need to bleed all the rads depends where you dropped the system out from, dont run the system till its all full as you may kill the pump running it dry!

 

[beefcake01uk]

Blead all rads. The ones downstairs were fine, but all downstairs dont get warm. Blead upstairs rads, 2 heat up 1 doesnt.
Iv had to cap the bathroom rad, as it was getting late so theres no rad in the bathroom yet.

 

[bunny78]

could you tell if the pipe work to the new rad is full of water? you may have a leg of air running up to the caps?
Downstairs rads must off been "drop feed" if they were full.
When you fit the new rad it should just need "balancing out".
Hopefully job done.

 

[beefcake01uk]

Cant really tell but id prob say no, theres no water in them. Ye downstairs are drop feed. Lets hope so ill try tomorrow. Thanks for your help Bunny78

 

[Bernie2]

Shut off all rads. Turn boiler off but keep pump on. Then progressively go around the house turning on rad, bleeding it, then turning it off. When you have got water to them all turn boiler back on and do the same but don't bleed the rads.

The idea is to start releasing any trapped air by forcing the water along the system rad by rad. The same for the heated water to each rad.

Watch out for any strange noises, as you may not have a by pass fitted and turning the rads off could cause venting over or the pump to burn out if its not getting any water to its inlet or can't get it pumped away. If so leave one rad open preferably the furthest away from the boiler.

Have you checked for sludge?

Some times even this doesn't work and what has happened is that you have an air lock down the system cold feed. But if your getting water out everywhere then its probably not that.

Its a case of doing it bit by bit and being patient

 

[Puddle]

One of the worst things you can do on a open vented system ,is to partly drain it and then refill,even if you know about heating systems they can still give you a right run around with air locks
Drain the system again draining all radiators as well,finish your work on bathroom radiator then after opening any motorised valves,refill,starting on the ground floor then upwards,do not vent to fast fill a radiator then wait for tank to stop filling then go to the next ect
when all full turn boiler thermostat down and run pump for 10-15 mins,then set boiler thermostat to normal,hopefully all will be ok
however If still a problem turn boiler stat down again and let pump run for a few hours

 

[REDSAW]

major tip of the week,
if you have 'a very old system' dont mess with it, call a plumber.
it has been running for so long, disturbing it or the pipe work only induces failure.
good-luck.