Draining down when a radiator bleed valve is broken

[itsfreezinghere]

Hi.
This is probably a stupid question but I'm told my combi boiler needs draining for a repair but the boiler isolation valves cannot be shut so the system will have to be drained. Unfortunately the radiator in my bedroom can't be bled so I don't want it to be drained if it means air getting in when refilling - it was always the only rad that used to need regular bleeding but is OK at the moment. If the valves in and out of the rad [the one that adjusts the flow/temp - not thermostatic - and the similar one on the opposite side - as if you didn't know!] are closed before draining and only opened again after refilling and running the boiler and bleeding the other rads [?], what are the chances of [much] air getting into that radiator? If it's unavoidable I'll put the job off for a while. Yes, I'll need a new rad, and boiler, but in the mean time...?
Thank you.

 

[Knappers]

May well be ok as you suggested, better still the longer you can keep rad isolated after work (atleast a few hours if pos).
I assume its an older round top rad with grub screw?
More sense financially to replace rad at same time if system is going to be fully drained, or have a good go at getting the screw out and possibly avoid new rad?

 

[Knappers]

I would just replace rad but you could try carving a slot in the stub with a terminal screwdriver and unscrewing or tapping one edge of the stub to try and spin it anti clockwise or drill a tiny shallow hole in the middle then tap in an appropriate tiny torx bit and unscrew???

 

[Ben-gee]

If it’s a standard panel rad, replace the bleed valve when you have the system drained?
Point out the problem rad to your plumber (before they arrive to do the other job!) and they’ll advise you - either change the valve or the whole rad - either would be an easy job whilst system drained.

 

[itsfreezinghere]

Hi.
This is probably a stupid question but I'm told my combi boiler needs draining for a repair but the boiler isolation valves cannot be shut so the system will have to be drained. Unfortunately the radiator in my bedroom can't be bled so I don't want it to be drained if it means air getting in when refilling - it was always the only rad that used to need regular bleeding but is OK at the moment. If the valves in and out of the rad [the one that adjusts the flow/temp - not thermostatic - and the similar one on the opposite side - as if you didn't know!] are closed before draining and only opened again after refilling and running the boiler and bleeding the other rads [?], what are the chances of [much] air getting into that radiator? If it's unavoidable I'll put the job off for a while. Yes, I'll need a new rad, and boiler, but in the mean time...?
Thank you.

I would just replace rad but you could try carving a slot in the stub with a terminal screwdriver and unscrewing or tapping one edge of the stub to try and spin it anti clockwise or drill a tiny shallow hole in the middle then tap in an appropriate tiny torx bit and unscrew???

Thanks. Sadly, I tried most of that when the bleed valve broke but with no success and now there's nothing left to work with.