Radiator issue and valve change

[stender]

I have a rad, lowest in house and drain point. It works intermittently and today when heating was on it wasnt warm at all and neither pipe felt warm. I turned the valve to check and it sprung a leak. Tried to close it and leaks worse. Managed to open it again and slowed the leak with some fernox lx. Is there an easy way to switch valves without draining? Eg lots of towels amd be quick. I know i should replace thermostat as well but that means draining

 

[terryplumb]

Is your central heating system sealed / pressurised ,or fed from an F & E tank
in the loft ?
Yes ,it's possible to change a rad valve without draining the system.

 

[stender]

I have a water tank in loft and emersion heater.

 

[terryplumb]

Your system is open vented ,you would need to bung the f&e outlet and the expansion pipe ,if you intend to swap a radiator valve without draining the system. If this isn't done ,and the system can suck in air at any point on the system you may get quite wet !!

 

[stender]

So unscrewing the valve nuts, lots of towels and quick switch not a good idea?

 

[terryplumb]

I assumed your loft tank was an F&E feeding the heating. It would be the smaller of 2 loft tanks ,is that so ?
If you are confident to snatch the valve then go for it ,if not drain down.

 

[Elkato531]

Sometimes its worth paying a pro to do the job. A plumber who knows what they're doing should be able to swap the valve without draining and charge you for an hour plus materials. You could bung the F&E and try it yourself but if you get it wrong you run the risk of getting wet. If you try and snatch it, you will get wet. If you drain down, the job spins out to half a day or more with the possibility of airlocks etc when refilling.

 

[nicam49]

There's a really gr8 youtube guide on exactly what you're asking about! I'll post the link when I find it...
This guy is really good!