Drain Point on System

[nfollows1982]

Morning all,

Sure this will be a quick one for someone to answer........

I've searched high and low on the pipe work for a drain point and there is definitely not one on any of the downstairs radiators.

The only one I have found is this one which is located on the pipework at the side of the boiler (downstairs):

Untitled

• nfollows1982
• 30 Sep 2014
• 1

2 questions really - is this the drain point that I need to use and secondly will this drain the downstairs radiators considering that this valve is higher than the downstairs rads?

If it helps I have system with a header tank in the loft.

Thanks

 

[Newboy]

If you need to drain down the d/s rads then you will need to either find a drain point at the lowest point of the system or cut in a drain point if one can't be found.

The obvious question - why do you need to drain down the entire system?

 

[nfollows1982]

I thought that might be the case!

The lockshield valves are leaking on a few of the rads, one of them is completely gone so I've had to close it.

So I'm going to drain the system and fit new lockshield valves, possible new TRV's too as the ones we have now are not doing the job properly.

I've seen a lockshield with a drain point on it to fit when I'm carrying out the repairs but what's the easiest way to drain without a drain point?

I've read about using a self cutting washing machine tap, looks simple enough just worried about replacing a section of pipe when I'm done.

 

[Newboy]

Self cutting tap is probably the easiest way to go - just be patient - the flow rate through them is lousy!

Choose a decent location on a straight pipe run so that you have room to fit a tee and a draincock once the system is drained down.

 

[nfollows1982]

Sorry to sound thick, but is that straight vertically or straight horizontally or doesn't it matter?

There is some pipework that runs under a floorboard just inside the back door that is easily accessible so would I be able to fit the drain tap to that section?

Also, can the tee fitting be a compression fitting or will it require soldering?

I think I could manage to isolate one of the rads, probably the bathroom one, just want to be sure what I think is the right way to do that actually is!

So I turn off water supply to heating system, then turn off both the lockshield and the trv valve to this radiator?

Then drain this radiator by unscrewing the connection to one of the valves and then remove the rad once it's empty?

I then fit a hozelock fitting to one of the valves and turn it back on once the hose is connected to drain the system? Do I use the lockshield or the TRV end?

Then assume I can fit a lockshield with a drain valve to that rad?

 

[alan333]

I've searched high and low on the pipe work for a drain point and there is definitely not one on any of the downstairs radiators.

Have a good look elsewhere for the drain cock, it's common for them to be sticking out of an air brick or something outside, a bit like this...

http://mybuilder-uploads.s3.amazonaws.com/2_thumb/1737643_2d8c2fc9f0.jpg

If your drain valve is higher than the bottom of the rads then it won't drain them, it'll only drain the system down to the drain valve height.

You're correct about isolating a rad and draining from it's valve, I drained mine from both valves. You can get away with draining into a basin if you want to save fitting hoses etc, but you'll inevitably spill some somewhere, so choose one where you can mop the floor rather than stain a carpet. Beware you'll almost definitely get some water out of every rad/valve you remove, so be ready with a basin and cloths anyway. It'll drain quicker if you let some air in somewhere above you, so maybe open a bleed valve(s) on an upstairs rad.

Our house has concrete floors with the rads fed from above, and each downstairs rad has it's own lockshield drain valve. Maybe that would be your easy option for future draining, since you're replacing the valves anyway? This obviously won't drain the pipes below ground tho.

 

[kbdiy]

For now you will have to drain via the rad connections by the sound of it. Turn off the rad completely, lockshield and TRV or wheel valve. Slacken one end of the rad and drain into a suitable container. Use plenty of protection as there will be some spill. Let some air into the rad to speed up the process. Easier if there are 2 of you so one can empty the container as you go.

When the rad is empty I would remove it to give better access. The you can drain from the lockshield and TRV. As mentioned, let some air in from higher up the circuit to speed things along.

You will need to repeat this for each downstairs rad. When you have drained you can think about the best position for a drain valve. The lower the better obviously. I have teed into both flow and return pipes at the lowest point on my system and run direct to drain valves just through the wall above a convenient foul water gully, so draining down is now an easy task.

Give everything a good flush with a hose before refitting and add inhibitor when you finally refill.