Upstairs radiators won't fill with water

[pickersm79]

Hi There,
Hope someone can help with this problem as my house is getting pretty cold!

I've changed a radiator on Saturday and once the new one was connected I can't get the CH system to work.

I changed the radiator by closing the valves at the bottom, draining and then installing the new one. But when putting the CH back on the boiler just cuts out.
I've had this problem a lot in the past and it's been due to airlocks in the system which are extremely difficult to get out. Both times I've had work done it's taken the plumber half a day to get the system going again.

I bleed all the radiators from the bottom of the house then up to the top and bleed the valve next to the CH tank but my boiler still wouldn't start.
The only option that's worked for the plumbers in the past is to drain the system and then refill. I tried this but now I can't get any water in to the radiators upstairs.
The downstairs ones filled up but very very slowly but 24 hours later and there's still no water in the radiators upstairs just air when I bleed them.

I don't know whether this is due to an airlock again or whether I've got a blocked cold feed which I've seen on this site can be the cause of this problem.
Problem is being no expert I'm not sure how to determine what the cause might be.

Any help is greatly appreciated!!
Thanks.

 

[combispecialist]

if u bleed the rad and no air or water comes out then its more likely blocked cold feed,quick check 2 confirm this would be to attach hose as if ure going to drain system,open draincock up then jump in loft 2 see if the small header tank is filling,if it isnt its a definate blocked cold feed

 

[pickersm79]

Thanks for that. I'll check that this evening.
It seems however overnight that the radiators have all filled up with water.
Bleed them all and bleed the pipe by the cistern but the boiler still refuses to come on properly. It comes on for about 10 seconds then switches off and has been doing that all day.

Would a blocked cold feed cause that or am I back to having an airlock?
Thanks!

 

[nogoodatfaultfinding]

if u bleed the rad and no air or water comes out then its more likely blocked cold feed,quick check 2 confirm this would be to attach hose as if ure going to drain system,open draincock up then jump in loft 2 see if the small header tank is filling,if it isnt its a definate blocked cold feed

Check what the man above says but i would go for.......................
A blocked cold feed to your system rather than the tank.
Get a good Magnet and place it on the copper in your cylinder cupboard, if it sticks anywhere then there is your problem(as magnets dont stick to copper) and the reason why you could not manually bleed the rads.
Other solution could be a blockage on your gate valve and this is simples.
1. Get a Hammer
2. Find ALL Gate valves
3. Hit with Hammer
4. Wait for woooooooosh noise

 

[pickersm79]

Thanks for your help. In the end it was just an airlock. I bleed the pump today and after that it all seems to be working fine!