Have removed one rad but now no heat

[alpinejim]

Help! I have removed one rad downstairs and connected the pipes in a U bend, thinking the flow would just continue on with no rad there.
Obviously there are no valves now so some of the system was drained down. Now i have no heat. The pump works as does the boiler, and i have hot water.
There is loud banging when i turn the heating on so i also tried bleeding other rads. Nothing much coming out there so i'm wondering if there's either a huge air block somewhere or no water in the system at all.
I checked a valve coming off the heating reservoir in the loft which seems to supply the pump and the boiler, it just spins, doesn't seem to open or close!
Is there a way of draining down completely and filling up from scratch?

Many thanks for any replies.

 

[minofso]

You didn't need to continue the pipe where you removed your radiator unless you have an old one pipe system. If this is the case then this will be where you have air locked.
If you have a flow and return system then just close the radiator valves each end and your system will continue to work. If it is the one pipe system, you should have put an air vent at the highest point in the pipe you connected.

 

[alpinejim]

Thanks for the response.
I guess i have a flow and return system as the pipes don't logically go from one rad to another.
The rad i removed was downstairs and as one of the pipes rises, it's highest point leads into what looks like an electrically operated switch/valve and then onto the pump. The second pipe rises up and branches off to other rads upstairs and also to a control valve that sits at the bottom of the immersion tank.
Should i install an air vent here somewhere or just open the pipe to release air?

Many thanks.

 

[alpinejim]

Sorry Minofso, just read your reply again.
As i have a flow and return system maybe i should break the U bend i made and terminate the pipes like the rad valves were still there?

 

[bobbilda]

The better alternative would be to remove both dead legs of pipework to where they tee into the system pipework.

As you have already connected both pipes via a 'u' and assuming this is the reason for airlocking you will not accomplish your goal simply by capping individually now. Any air would have had a better chance to escape whilst both connected.

By simply turning off both rad valves initially and capping these your system would have continued to work as per normal with possibly a little tweaking of the lockshield valve. Unfortunately you have made more work for yourself and unbalanced the system.

If you do decide to cap instead, consider installing doc's if there aren't any on these low points of the system. This will serve two fold a) you will be able to bleed each pipe individually thus return the system similar to its original condition and b) it will probably also serve as valuable drain points on future occasions.

You will also need to make sure that the valve that you described "that spins" is removed or at least has the inners removed. Assuming that this valve is on the system cold water feed from the expansion tank, this cold feed is also the system expansion pipe and should in no way be restricted.