How do I isolate my Vokera syntesi 35 central heating

[ottosump]

Hi group, I'm replacing a heated towel rail with a new radiator in the bathroom, I'm fitting new TRV & lockshield. My question is, how do I isolate the water supply to the central heating system so I can cut the pipes to suite, hope the picture included is adequate, Take care all!
Otto, from a sunny West Cumbria

 

[Hot&Cold]

Dont turn the boiler flow/return valves,they could leak water

Drain down the system.

 

[ottosump]

Thank you for the prompt reply O&B, how do I turn the water off at the boiler though, won't it just keep filling up?

 

[Hot&Cold]

won't it just keep filling up?

As long as the filling loop is turned off (shut) no water will enter the heating system. It should be already turned to shut.

 

[vulcancontinental]

When you've drained the system and completed the work open the round tap centre of your picture and move the lever on the other end of the braided hose so 'filling loop' is written the right way up. With both these taps open the system will refill. Bleed the radiators as it fills and don't let the pressure rise to high, aim for around 1.2 to 1.5 bar. Perhaps enable some help to turn off the tap if it fills too quickly while you're bleeding the rads.