Confusing back boiler removal - hidden equipment or broken water tank?

[zhuffzilla4]

Is the cistern filling via the ball cock?

Yes - ball cock in the top section of the water cylinder

Turning off a drain cock can not possibly stop flow somewhere else

If that is the case is it even possible to blank off the boiler (fireplace/radiator) circuit if the tank is prismatic?

 

[FiremanT]

Bit confusing this, mainly because a "plumber" has been involved, so your misunderstanding is even more perplexing.

I am guessing that the tank stopped filling when you turned off the draincock, simply because the system was full. The water level rises, pushing up the ball and and actuating the valve (closed).

What are you actually trying to achieve? How do you propose to heat the radiators, after removing the boiler?

 

[ianmcd]

As I read it @Fireman T he only has one radiatot teed from the gravity water flow and return so will be a heat dump probably

 

[FiremanT]

As I read it @Fireman T he only has one radiatot teed from the gravity water flow and return so will be a heat dump probably

Yea. You are right. I forgot that.

OP: If you are trying to just use the cylinder for HW via immersion: Isolate CW. Drain as you were. remember to open bleed on the (one ) radiator. System will empty. Cut F&R. Cap of F&R at THE CYLINDER SIDE. Do not cap pipes leaving boiler. If possible, physically remove boiler. If, for some reason, not possible to remove boiler, drill holes into boiler casting, and remove F&R pipes as close as poos to boiler. to repeat: DO NOT CAP OFF PIPES FROM BOILER.

Reinstate cold supply, the cylinder can now be used for HW only.

If there is a drain cock built into the cylinder, it may be worth checking to see if ot functions. Now will be a good time to replace it, if it will come out. THERE WILL BE LOTS OF WATER BETWEEN THE DC AND THE RETURN PIPE OUTLET