In the case the lockshield does not incorporate a drain off point, you should:
1. Put a bowl under one of the union nuts that hold the valves to the radiator
2. Then you should open the bleed valve at the top of the radiator and with a suitable spanner, loosen the union nut. Hold the valve steady not to let it rotate and wriggle the valve to break the seal. Do not loosen the nut too much, because it can lead to the uncontrolled water flow.
3. Let the water to drain into the bowl. Empty it some times as soon as it fills up. As soon as the necessity to tighten the union nut arises, empty the bowl. It is good to have a bucket for this purpose.
Disconnecting the Radiator
As soon as the water has drained from the radiator, you should connect the two union nuts with the valve. If you need to disconnect lockshield to the radiator, apply a suitable spanner to hold the valves steady not to give them to rotate. Wriggle each valve to break the seal. It is recommended to keep a bowl under the union nut. If you do not do it, some quantity of water will be released.
Removing the Radiator
Lift the radiator up and off of the mounting brackets and you will see some quantity of very dirty water on it. It is recommended to keep the radiator level while lifting it. Tip one end of the radiator into a bucket to get this water.
It is recommended to apply some form of capping for sealing off the thermostatic valve if fitted.
To avoid the entry of the ingress of dirt into the valves, you should cover them with plastic bags.
Refitting the Radiator
1. You should take away any capping that is fitted to a thermostatic valve and plastic bags that are fitted over the valves.
2. Then you are to lift the radiator back onto the mounting brackets. Its position should be horizontal to have the valves in contact with the radiator.
3. Then it is recommended to fit each valve in turn into the connection on the radiator and fit the union nuts. As soon as you tighten them by hand, you should fully tighten them with a suitable spanner. Hold each valve steady while tightening the union to avaid its rotating.
4. Be certain that you have turned off the central heating pump and you have closed the bleed valve.
Then observe the union nuts and other joints for the signs of leaks. If they are available, you should try to tighten up the joint.
5. Then you are to open the lockshield valve using by the same number of turns while closing it.
6. Then you should open the manual or thermostatic valve.
7. Then you should open the bleed valve at the top of the radiator to let the trapped air to go away, close the bleed valve as soon as water appears.
8. On closed loop central heating systems, you should check the system pressure and top up.
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