Is an external drain-off sensible?

[brewmook]

Hi,

My house has a drain-off for the central heating poking out of the wall.

No plumber has ever commented on this being a problem, but isn't it a risk in cold weather like this?

I've been down in the crawl space and it's lagged for a couple of metres in fairly old school wool-like insulation.

I'm about to do some re-piping and wondered if a drain-off on the return side of a radiator near the door would be less risky. It'd be higher than the current one though, as pipes are below the floor.

Any opinions out there?

Cheers,
Dave

 

[Gasmk1]

A lot of old school plumbers used to do this have seen loads over the years, never heard of any problems with them but there could always be a first time. If it freezes the Ice will expand back along pipe so shouldn’t rupture.

 

[Ben-gee]

Leave it, obviously a drain off at the lowest point is a good idea.
Could build a box around it and fill with celotex if you’re worried.

 

[BN9Pete]

If I have to drain down a heating system and find an outside drain off I think it’s my lucky day 😃

 

[IND_Nick]

When I first started, almost 20 years ago, the lads I worked for would do it on every new install, if the pipework was below the floor. It made life so easy when flushing or returning to do work. As long as it's sleeved and inhibitor in system I've never seen one fail/freeze.

 

[BN9Pete]

I had to fit an outside drain off recently on a system, i had 2 dark colour rads to fit that the customer had supplied, they had also bought matching valves and short pipes the same colour, pipes designed to go from the valves to the floor.
Soldering a tee and drain off into the spray painted pipe would have looked bad, the other ground floor rads on the system had pipes coming out of the wall and straight into the valves.
Easy drain down when I change their upstairs rads next year.

 

[Ben-gee]

Yeah it’s great, no risk of nasty black water on carpets - and in winter no need to have the door open with a hose going out.

 

[brewmook]

Cheers for the replies. Sounds unanimous!

It's not quite at the lowest point (some interesting plumbing under there!) but below all rads at least. If I get the hose on before opening up the rads it'll maybe syphon off the worst of it I hope. Or is that wishful thinking?

The drain is on the return side of a 2 pipe system. Will the flow side really drain, or should there be a route from flow to drain too?

I'm over thinking it, aren't I?

Cheers,
Dave.