Rounded off Heating Drain Valve

Jonnyhahn

Hi all
I'm trying to drain down my central heating system due to a leaking radiator in the living room. 
I have located the drain valve but it is correded in place and completely rounded. I have tried all I can to get it to budge but I am having no luck and it is rounded smaller than the key (it is currently at about 3/16 socket size.
Is there any other way of draining the system, and if not does anyone have any tips for getting the grub screw to move?
Many thanks! 

Hasbeen

Jonnyhahn said:

Hi all
I'm trying to drain down my central heating system due to a leaking radiator in the living room. 
I have located the drain valve but it is correded in place and completely rounded. I have tried all I can to get it to budge but I am having no luck and it is rounded smaller than the key (it is currently at about 3/16 socket size.
Is there any other way of draining the system, and if not does anyone have any tips for getting the grub screw to move?
Many thanks! 

Why drain the system to repair / replace radiator?

What is leaking. The radiator or any of the valves?

Is the system drain valve outside?


EDIt: grub screw? Are you talking about the bleed valve at the top of the radiator?

Grenage

You could file the sides flat and use an adjustable wrench/pipe grip, or possibly saw a slit so you can get a flat tool into the head.

Jonnyhahn

Hi
It is the copper pipe behind the radiator coming out of the wall that is leaking, on an old copper elbow. I assume the solder has failed? The drain valve is on the radiator closest the front door, and is the only one in the house. When I mean the grub screw, I mean the drain valve screw above the hose connector.
Ubfortuntaly it inside a collar, so I can't get anything in to be able to file the sides of the screw.

nofoollikeold

To drain system without a drain !!!!!!:
1. System off, feed to F&E tank off.
2. Remove and clean F&E tank without letting its water (and assorted muck) flow through the system.  Replace F&E tank.
3. Select a radiator near an external doorway.  Turn off both valves (noting number of 1/8 turns on lockshield valve to restore when work completed).
4. Slacken radiator bleed screw.
5. Slacken then remove nuts holding valves to radiator, catching water from radiator in trays / buckets / old cloths.  
6. Remove radiator, watching out for spillages of black water.  (Re-tighten bleed screw and carry radiator upside down).
7. VERY slightly slacken nut holding valve nearest door to pipes, swivel 90 degrees so open end facing you, then re-tighten.
8. Bind open end of hose pipe to open end of valve using lots of electrical insulating tape.  Other end of hose to drain.
9. Open valve, drain system.  Open each radiator's bleed valve starting at highest radiator and working down.  If water comes out of any radiator, re-tighten bleed screw and wait a bit for water to drain down from higher radiators.
10. To speed up, repeat 7, 8, 9 for other valve.
11. Carry out work as required. (in this case also replacing drain valve.  If soldering in, remove rubber washer first, then replace).
12. Make sure all radiator bleed screws shut tight.
13. Remove hoses and reconnect radiator used for draining.
14. Refill system.

Ganga

What I would do is is give the drain valve spindle a tap with a hammer and punch ,this should release it ,after you have drained the system replace the whole valve assembly for next time.
Do you have to drain the whole system ,can you not turn off the two rad valves and fix the radiator?