Draining a convy boiler to add another radiator help

[markymark2406]

I have a pressurised Valiant convo boiler and want to add another very small radiator in the toilet which is is on the 1st foor of a standard house now I sort of know what to do to drain and work on the system but just a confirmation I'm doing it correctly so to turn off the flow and return there are 2 valves under te boiler close them? Then drain the system by the tap down on one of the rads downstairs? When I have done the work open the 2 valves again on the boiler and fill with the 2 taps under the boiler bleed the rads out as I do?[/quote]

 

[denso13]

No need to close the valves at the boiler. Drain down, fit radiator and bleed all radiators. Put in new inhibitor as required.

 

[markymark2406]

Well it's upstairs so am I right in saying that the rads on that floor just need draining and when obviously below that level I can do that work? What about inhibetwr how do I get that into the system? Obviously easier years ago as you put it in the header tank in the loft

 

[denso13]

Yes, you just need to drain it until it is below the level you're working at. Put the inhibitor in the empty (new) radiator before you open the valves and bleed the radiator. It will soon circulate round the system.

 

[Agile]

Not all will agree, but is you close boiler valves first and keep it pressurised then you can still get some hot water while you are working on the rad.

Its better not to seriously over use the DHW in that condition though.

The thoughts are that the boiler dumps heat into the heating system after using hot water. The reality may be different.