Lets assume then that:
1. You've tested it with open flow and return pipes.
2. The return pipe has adequate water going through it.
3. Therefore, the blockage, if any, must be in the flow pipe.
4. If you flush with mains pressure water from the open end of the flow pipe after removing the pipe from the offending radiator there is a risk that you will flush the blockage to some other place in the system.
5. If you find the other end of the flow pipe, which will either be at the zone valve for the heating, or at another, working, radiator, then:
5a. Disconnect it at that other end;
5b Flush through to the open pipe end located by the offending radiator. Doing so will tend to flush any blockage out of the open end, and no doubt into a bucket, rather than back into the system.
1. You've tested it with open flow and return pipes.
2. The return pipe has adequate water going through it.
3. Therefore, the blockage, if any, must be in the flow pipe.
4. If you flush with mains pressure water from the open end of the flow pipe after removing the pipe from the offending radiator there is a risk that you will flush the blockage to some other place in the system.
5. If you find the other end of the flow pipe, which will either be at the zone valve for the heating, or at another, working, radiator, then:
5a. Disconnect it at that other end;
5b Flush through to the open pipe end located by the offending radiator. Doing so will tend to flush any blockage out of the open end, and no doubt into a bucket, rather than back into the system.