Possible Freezing of a Tap

[self builder 123]

Hi

I have a garden tap recessed into a concrete wall.

I have a stop valve fitted below ground between the water supply and the garden tap. The plastic pipe runs up the wall to the tap from the stop valve.

In the winter we planned to close the stop valve and open the tap allowing the water to drain.

By leaving the tap open I figured that the water remaining in the pipe work rising up to the tap if it were to freeze would have room to expand and thus prevent the pipe work from possiblly bursting.

Is this correct ?

The garden tap currently has a building in double check valve. Would this stop the water from being able to expand as it would close when the stop valve was closed as there would be no pressure behind it ?

 

[Softus]

In the winter we planned to close the stop valve and open the tap allowing the water to drain.

I don't understand how you can "plan" for the water to drain vertically upwards.

By leaving the tap open I figured that the water remaining in the pipe work rising up to the tap if it were to freeze would have room to expand and thus prevent the pipe work from possiblly bursting.

Is this correct ?

No. Water doesn't expand until its solid, and ice doesn't flow uphill.

The garden tap currently has a building in double check valve. Would this stop the water from being able to expand as it would close when the stop valve was closed as there would be no pressure behind it ?

No. Most DCVs are destroyed when subjected to expanding ice.

The only cheap option available to you is to suck the water out with a wet vac, but even that isn't guaranteed to get all the water out.

 

[Shytalkz]

Why not just put some insulation around the pipe to stop it freezing in the first place?

 

[Softus]

Why not just put some insulation around the pipe to stop it freezing in the first place?

That won't stop it freezing.

Insulation slows down heat loss, it doesn't stop it. There is still a risk that the temperature would be low enough for long enough.

 

[Shytalkz]

True. More insulation then

 

[Shytalkz]

Why not just put some insulation around the pipe to stop it freezing in the first place?

That won't stop it freezing.

Insulation slows down heat loss, it doesn't stop it. There is still a risk that the temperature would be low enough for long enough.

Ok, semantically adjusted to read "Why not use sufficient insulation of a type and quantity capable of resisting the transformation of the liquid within the pipe to a solid state, for a sufficient length of time suitable to allow a return to warmer ambient temperature, where said state of transisition is no longer deemed a risk?"

 

[Aqua]

In our business we 'drain down' watering systems in autumn and i would say that by turning off the stop valve and opening the wall mounted tap you should get a little water running out of the tap, just by the pressure in the pipe. Then if the water in the pipe did freeze it would have somewhere to expand to, with the tap left open of course.

In truth we don't get the long hard freeze ups in winter these days, however, a couple of hard frosts would be enough to split the pipe so a good deal of pipe lagging would certainly help to prevent freeze up.

A better way to solve your problem, however, would be to loosen the connection above your stop valve (valve closed) to allow water to drain out of the pipe from the tap end, with the tap open of course. Therefore the pipe would be empty and could not freeze.

You don't say if you can get to the stop valve or not with tools, but that is what i would do.

Again though, if the stop valve is exposed to the elements (and the pipe beneath it) then that could also freeze up, damaging the valve.

 

[Aqua]

Hi

The garden tap currently has a building in double check valve. Would this stop the water from being able to expand as it would close when the stop valve was closed as there would be no pressure behind it ?

Didn't read your post properly the check valve would indeed stop water without any pressure behind it.

Therefore any water in the pipe would be trapped between the 2 valves (stop valve & check valve) and in the event of freeze up would eventually burst the pipe. I have seen frost burst a galvanized steel pipe with ease.

Still, i think my earlier suggestion of draining the entire pipe down (or most of it) would be your best solution.

Post a photo on here if you are in any doubt.

 

[self builder 123]

Hi Aqua

I am grateful for your comments regarding my concern of the pipe freezing in the wall.

You mentioned uploading a photo. Would you mind if I were to e-mail the photo direct to you to see what you think ?

Cheers

 

[Aqua]

self builder 123 please check your in box.

Or,

As i understand it you can post a photo here by using photobucket quite easily.

 

[Softus]

You don't even need Photobucket - the site offers a natty image uploading/storing/using feature.

See here:
//www.diynot.com/forums/viewtopic.php?t=129539
and here:
//www.diynot.com/network/user_album.php

 

[Aqua]

You don't even need Photobucket - the site offers a natty image uploading/storing/using feature.

See here:
//www.diynot.com/forums/viewtopic.php?t=129539
and here:
//www.diynot.com/network/user_album.php

Nice touch by the site owner/mods, so self builder 123 lets see your photo

 

[Aqua]

Come on self builder 123, have you disappeared or frozen up