Rad Valve Cap

[nordberg73]

Hi
Please see attached image. The builder left the radiator valve like this. I have a TRV to go on, but I expected the cap would just unscrew and I would screw the TRV on. When I loosened the cap, water spurts out from the system. Do I need to drain the whole system to fit the TRV??

 

[Madrab]

Fit the rad first and then fit the TRV head. That's the decorators cap on the valve and the valve will open if removed.

 

[nordberg73]

Fit the rad first and then fit the TRV head. That's the decorators cap on the valve and the valve will open if removed.

Thanks so much! Makes perfect sense!

 

[nordberg73]

Just to confirm as I can’t quite get my head around it... I fit the rad and connect the flow/return. I then remove the decorators cap and fit the TRV head. There will be no water escape when I remove the cap? Why?

 

[Madrab]

When you connect the radiator up at both ends, it make a water tight seal with the system, therefore no water should leak out when the cap is removed, all it should do is fill the radiator. You then need to bleed the radiator whilst topping up the system pressure.

May be an idea to ask the chap that took the rad off and added the decorator cap to refit the rad, bleed the system ad fit the TRV.

 

[nordberg73]

When you connect the radiator up at both ends, it make a water tight seal with the system, therefore no water should leak out when the cap is removed, all it should do is fill the radiator. You then need to bleed the radiator whilst topping up the system pressure.

May be an idea to ask the chap that took the rad off and added the decorator cap to refit the rad, bleed the system ad fit the TRV.

Gotcha! I understand. Thanks again!