Radiator valve drain off

[sirkuk]

I was looking to drain down my CH system this weekend to fit TRVs throughout the house as none were ever fitted downstairs and half of the upstairs valves are stuck open or closed but I seemingly have no drain off.

I do however have a T piece lockshield on all of the downstairs radiators with an 8mm spigot. Are these drain off points? If so, any recommendations to what I can use to attach to them? I’ve attached a photo.

Curiously, why would every downstairs radiator have one if it’s a drain off? My only thought is that the feed and return for each of the downstairs rads is coming from above?

Final question is if I’m just better off plugging the vent and feed in the loft tank and not draining? I have 10mm piping to each rad and something tells me it’ll be an ar*e to get the air locks out afterwards on refill.

Cheers

 

[terryplumb]

Put a hose on the spigot to drain. If you only had 1 rad with a drain cock ,the other rads on the same level would still be full of water ,so they all have one. I wouldn't advise a DIY er to work on a system still full of water and just bunged. Best to drain out , a lot less chance of flood !!

 

[sirkuk]

Thank you for the advice. Draining down was my gut feel so I could take my time but wasn’t sure if it was overkill for replacing a valve. Just need to find some 8mm ID pipe now.

 

[terryplumb]

If you are prepared to lift off a rad ,you could drain via the rad valves.

 

[sirkuk]

Amateur question but what fitting/hose would you use to drain from the rad valve? Or would you just catch in a tray under the rad valve and stop/start as it fills?

 

[terryplumb]

Turn off both valves on the rad. With tray / bucket / sponge / cloths handy ,undo the nut that connects ONE valve to rad ,catch water in tray below. Open air bleed at top of rad ,this rad will now drain out.undo the other valve from rad. You can now lift off and remove the rad. It depends on the valve thread ,as to what will connect to it ,but I use flexi hoses ,one with 1/2 inch or the other 3/4 inch bsp threads ,female at one end and 15 mm copper at the other connected to hose. But you can just run out via buckets.

 

[sirkuk]

Thank you. For the sake of convenience, I’ll grab a flexi like you suggested and drain off fitting to connect to a garden hose.

Thanks for your help. It’s clearer in my head now what I need to do.

 

[terryplumb]

OK , be aware that your valves look very old and their threads may or may not be 1/2 inch or 3/4 inch. So buckets would be plan B !!!