Rad valve swap - drain down?

[JayJay1978]

When plumbers swap rad valves on vented systems they do the trick with the two caps to create vacuum etc, but is there a similar way on a combi system eg; downstairs rad?

Or is it complete drain down for downstairs?

 

[clf-gas]

Yep, Issolate boiler, crack open said valve tale system releases pressure and vacume will form.

In brief

 

[JayJay1978]

Thanks for that, just out of interest is it wise to mess with boiler isolaters, do some leak afterwards making you wish you'd drained down?

 

[BingoBongo]

Thanks for that, just out of interest is it wise to mess with boiler isolaters, do some leak afterwards making you wish you'd drained down?

ohhhh yesssssshhh

what kind of boiler is it.

do you know where the drain valve is? Should be a lot simpler

 

[gaspro1981]

Thanks for that, just out of interest is it wise to mess with boiler isolaters, do some leak afterwards making you wish you'd drained down?

oh yes be warned worcester, potterton and vokera are the worse culprits

 

[clf-gas]

Thanks for that, just out of interest is it wise to mess with boiler isolaters, do some leak afterwards making you wish you'd drained down?

In all honesty Jay yes some do, Its more down to judgement on the day. A full drain down will be more time new inhibitor and more money

 

[JayJay1978]

I have a vented system myself but I've always wondered if this could be done on sealed system.

Just so I can get my head round it, is closing the automatic air vent in the combi the same as shutting iso's off? Is this a less risky method?

 

[namsag]

On a sealed system if you dont want to touch isolating valves or there is none . just screw the auto airvent caps down to stop any ingress of air and that will do trick.

 

[kirkgas]

i've done loads of live swaps on rad valves on combis, i always check the rad is full of water (by airing it) before i swap valve, as i think any air in the rad will allow water to spill out when you disconnect the valve, but if full of water it cant get out