On Dec 23, 8:43*am, harry wrote:
On Dec 22, 4:06*pm, MM wrote:



On Dec 21, 7:30*pm, " wrote:

On Dec 21, 7:26*pm, David J wrote:

On Tue, 21 Dec 2010 12:40:26 +0000, The Natural Philosopher

wrote:
wrote:
I'm about to go away for a few days, and usually I would switch the
central heating thermostat down to the frost setting.

That of course will be sufficient to ensure that the pipework inside
the house won't freeze, but my feed & expansion tank is in the loft -
and with the exceptionally cold weather, I could imagine that might
freeze.

My system is a thermal store (i.e. large volume of water), so hot/cold
cycling actually results in a fair bit of movement of the water level
in the f&e tank. I'm guessing that because it's never off for more
than 8 hours on the current timer settings, that any ice "skin" in the
tank gets broken up by the movements in water level.

So I think I'm going to play safe as temperatures are remaining below
freezing for days - and leave the system on its normal settings.

But I'd like to hear - are f&e tanks freezing a real problem?

Yes.

Are burst pipes elsewhere in the system (due to inadvertently creating
a "sealed system") a possible outcome?

Yes

Some years ago a neighbour drained their tank in the loft because they
were off to Spain for a couple of months to miss the worst of the
English winter. On their return, in chilly February, they turned on
their main water stopcock and got their c/h running.

After a while there was a horrible rushing noise from upstairs, and
water was seen pouring through the lounge ceiling.

The ballcock in the tank had stuck in the down position....

David J

One would hope the overflow could cope with that.

NB: The overflow ~can~ freeze up, thus no longer behaving as an
overflow! That's yet another job to take on for next year: What to do
to prevent that from happening. Although I have the water alarm
mentioned above, I don't hear it very well from 50 miles away!

Maybe that's the next level of technical wizardry: a water alarm-cum-
wireless thermometer that "phones home" when there's a problem.

MM- Hide quoted text -

- Show quoted text -

Best thing is to get a mains pressurised system and do away with all
plumbing in the loft.

Well, my system is a bit weird, although the house is only 6 years
old. There ~is~ a large cold water tank, but it doesn't feed the cold
taps! It ~only~ feeds the hot water cylinder in the airing cupboard. I
know this because if I turn on any cold tap in the house the water
level in the cold tank doesn't change, even after 5 minutes, and thus
the ball valve never opens. Also, the cold taps all have really high
pressure, just like the kitchen cold tap, which traditionally was the
one connected directly to the water main. I have high pressure
doubries in the toilet cisterns, too.

I tell you what I have been mulling over these past few days: As I go
to Germany fairly regularly I can buy the still widely-used
Tauchsieder from Karstadt or other similar department stores. I have
one at home at the moment and use it for wellying up the water in the
bucket when washing the tiles and similar heating jobs. Nifty!

Now, imagine one of these dipped into the cold water tank! On a time
switch, you could warm the water a tad every few hours throughout the
night during these very cold nights -- sorted!! My Wilkinson
electronic timeswitch (£5.97) has 10 on/offs. (Don't buy the
mechanical segment type; they're crap long-term. Both mine stopped
working after only a year or so. Unreliable.)

In case anyone doesn't know what a Tauchsieder is, they look like
this: http://www.amazon.de/Relags-Reise-Ta.../dp/B000KBEWQW

MM