Drain on Central Heating System

[ChrisPaws]

I have almost finished fitting my new central heating system and have a question about a good location for a drain valve. I am proposing to put an extra long copper tail on the return side of a rad which happens to sit on a downstairs suspended floor with a deep void below. This will natually create a low point in the system, I can clip the pipe to the underside of the suspended floor (saving work) and it has great access, including outside to a foul water drain. I propose to create the long tail and solder a tee to the end with one side soldering on the drain and the other just joining back in to the main return. Is there any glaring reason why this shouldn't be done? it makes great sense to me.

 

[Alpha man]

Run it under the floor to the outside with a drain tap outside, but keep up from the ground (outside) about 12" so it dosent get covered in snow and can freeze, Dont forget to lag it well out side and under the floor,

Best practice would be just to put a drain point near the front and back door rads, and dont worry to much whats under the floor, cos when the pressure is off its manageable.