Heat loss via external drain cock?

[Super_Paulie]

Morning everyone, nice and warm today.

 

I'm looking to fit an external drain cock to completely drain the central heating when the need arises. So the lowest point is obviously under the floor and I was going to just tee into the closest rad flow and bring the pipe straight out the wall with the cock on the end, a run of maybe 40cm, pretty simple stuff. But my question is, am I just going to be haemorrhaging heat outside via the drain cock? As it's all under the floor level I can't really get an isolator that I can access on there. Water won't be flowing through the leg but the heat will transfer through the water/pipe. Or am I worrying about nothing here as it will be miniscule?

 

Cheers guys.

[Conor]

I wouldn't bother, just have a length of flexible piping the clamp on to a radiator drain valve. You just make sure the end of the house is below the lowest point in the system and it'll drain fine. You'll likely be flushing out anyways so not an issue 

[Super_Paulie]

It just seemed an easier way to get rid of a ton of old heating water as the cock would be directly over a gully.

[saveasteading]

Either way, it won't empty the pipework that is in the floor unless you can get a siphon outside. 

I don't know if that matters.

[Super_Paulie]

Nah that won't matter really, it's just to get rid of the majority at radiator level.

Im just unsure as to having the cock outside is essentially losing a shed load of heat at all times.

I could probably have it on an isolator but that would haveto be under floor level, so mightily inconvenient.

[saveasteading]

2 hours ago, Super_Paulie said:

essentially losing a shed load of heat at all times

it is easy to insulate with a standard tap cover, plus you can box it in and stuff the box with insulation if you want.

 

BUT i agree with @Conor  that a hose is simple, and how often would you do it?

[Super_Paulie]

That was my initial idea but the wife had other plans with some fancy valves, copper left on show etc...

 

Not planning on doing it a lot, it's just while the gaff is a building site now would be the time. I'm still in 2 minds about it...

[marshian]

I've got a drain on the flow and return CH pipes that comes from the lowest point under the suspended wood floor and go straight out thro the wall and drain points are accessible via a small hatch in my decking and drain onto the gravel under my decking. only thing that is outside is the drain valve - I really should check one day if either of them actually get warm???

 

Picture taken before the pipes were lagged and before I put the 75mm PIR insulation above them under the floor

 

Drains valves are to the right to (External to the house)

 

Upper 22mm is the end of the flow and return pipes

 

The pipes going to the left and up and to the left and the feed and return for the last rad on the system

 

The pipework for this rad was a real dogs breakfast as it had been moved from one wall to another and the extended pipework wasn't lagged at all!!!

 

I found similar around the rest of the house when I was under the floor