Draining a radiator

-chris-

Hi,

I need to replace one of the radiator bleed nipples downstairs but before I do that, I need to drain the upstairs radiators before draining the radiator downstairs. 

I’ve never drained a radiator before but I’m assuming I need to do something with the pointy bit at the top in the pic below so the water drains out of the bit pointing towards the floor. 

Any help, advice or pointing me in the right direction would be appreciated.

Thanks

grumbler

Very odd. It's definitely the part in the middle, not the left one, but I'd expect to see something like this -

- with a screw at the top.

ETA: you don't need to do this upstairs first. you can do this only downstairs - at the lowest point.

neilmcl

Do you have any drain valves on you downstairs radiators that look like the one here: https://www.screwfix.com/p/chrome-angled-radiator-valve-with-drain-off-15mm-x/70408

FreeBear

grumbler said: you don't need to do this upstairs first. you can do this only downstairs - at the lowest point.

If the radiator that is needing a new bleed screw has the same drain point, there is no need to drain the whole system. Close off the valves at either end of the radiator (counting the number of turns). Pop a bowl under the drain spigot, and let a bit of water out. Remove the bleed screw, pop a new one in, and open up the valves.

[Deleted User]

Hi.

no need to drain radiators, I've fitted auto vent/auto bleed valves to my radiators without doing so.

Turn off water at both ends  of radiator, note number of turns for lockshield valve, remove faulty valve and replace with new valve, open lockshield valve same number of turns.

Be prepared, with cloth or container to catch drips of small amount of water escaping when removing valve.

Would recommend fitting auto bleed valves, you're having to do the job anyway, and saves having to go round bleeding every now and again.

Google auto bleed valve for more info.

neilmcl

As above, if all you're doing is changing a bleed valve then there's really no need to drain anything. Simply isolate the radiator, bleed off any excess and remove the valve, taking care to catch the small amount of water that will come out and fit the new valve. Get an Autovent valve

nofoollikeold

1. As stated above, you don't need to drain the system, or even the radiator you are working on, to change the bleed valve.
2. You will however need to turn off the valves at both ends of the radiator.
3. To turn off the valve in your picture, use a spanner or key (NOT pliers if you can possibly avoid it) to turn the squared off bit at the top.  Turn it clockwise looking down on it, and count the number of 1/8ths of a turn required to fully close it.
4. The valve at the other end my be a TRV or similar to the one in your picture.  If TRV just turn it to zero, not to any "frost" mark.  If not a TRV, treat as 3. above, unless it has a handle / knob, in which case use that.
5. Then as frugalmacdugal says.
6. I personally wouldn't fit auto bleed valves.  If you get a lot of air in the radiators it will be because of a problem, and one you won't notice with automatic valves.  

Homer_home

What everybody seems to have forgotten to tell you is you might need to add more water to your rad to repressurise it to the correct bar and whether you fit auto bleed or not 

Depends on your system though do you have an open vent or sealed central heating system?

nofoollikeold

If you are just changing the bleed valve, you won't lose any water from the radiator, at least not more than a few millilitres, so shouldn't have to add more water.

-chris-

neilmcl said:

Do you have any drain valves on you downstairs radiators that look like the one here: https://www.screwfix.com/p/chrome-angled-radiator-valve-with-drain-off-15mm-x/70408

No, they’re all the same in the op

-chris-

Homer_home said:

What everybody seems to have forgotten to tell you is you might need to add more water to your rad to repressurise it to the correct bar and whether you fit auto bleed or not 

Depends on your system though do you have an open vent or sealed central heating system?

It’s a sealed central heating system