Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the winter.


--
Michael Chare

Michael Chare wrote


Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the winter.

http://www.kamco.co.uk/Freezbreaker.html

Michael Chare wrote in
o.uk:

Is it practical to put anti freeze in a domestic central heating
system to stop the water freezing if the system is left switched off
in the winter.

Yes - that's what they do in Sweden, using glycol.

Harry

Does seem odd to put in heating then turn it off when you most want it
though.
The only thing I have encountered is a neighbours evaporation thingy.. It
probably has a name, which regularly gets stuffed up by ice and icicles hang
from it.
Then boiler complains and cuts out as I recall.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Michael Chare" wrote in message
o.uk...
Is it practical to put anti freeze in a domestic central heating system to
stop the water freezing if the system is left switched off in the winter.


--
Michael Chare

On 08/09/2014 12:37, Michael Chare wrote:
Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the
winter.


There's nothing special about antifreeze. To a good approximation,
depression of freezing point depends *only* on the concentration of
additive, not what chemical it is.

Normal CH inhibitor would have pretty much the same effect
mole-for-mole, and you need that anyway.

--
Reentrant

On Mon, 8 Sep 2014 13:05:37 +0100, "Brian Gaff"
wrote:

Does seem odd to put in heating then turn it off when you most want it
though.
The only thing I have encountered is a neighbours evaporation thingy.. It
probably has a name, which regularly gets stuffed up by ice and icicles hang
from it.
Then boiler complains and cuts out as I recall.
Brian

Condensate drainage pipe.

--

Graham.

%Profound_observation%

On Mon, 08 Sep 2014 12:37:47 +0100, Michael Chare wrote:

Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the
winter.

So the CH doesn't freeze but other water pipes do, hum...

Think you'd be better off spending the money on a frost stat.

--
Cheers
Dave.

Michael Chare wrote:
Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the
winter.


I'd have thought it was a waste of time unless you also drain down all
the other water pipes in the house. You are likely to need up to 100L of
antifreeze to do a house. Looks like up to £5 per litre.

In article ,
Michael Chare writes:
Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the winter.

You can buy combined inhibitor/antifreeze for this purpose (e.g.
Sentinel X500), but it's not cheap because you need a much higher
concentration than is required for standard inhibitor alone
(typically, system needs to be something like 30% anti-freeze).

One of the former regulars here (Andy Hall) did this for a separate
heating circuit which passed under his garden to heat his workshop.
Because of the high cost of the antifreeze, he included provision to
drain that circuit into a tank which allowed the antifreeze to be
reloaded rather than lost.

As others have said, the heating system is only one type of water
pipework which might freeze, and you will need to tackle the others
someway too.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 08/09/2014 16:33, Capitol wrote:
Michael Chare wrote:
Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the
winter.


I'd have thought it was a waste of time unless you also drain down
all the other water pipes in the house. You are likely to need up to
100L of antifreeze to do a house. Looks like up to £5 per litre.

On freezing a diluted mixture of antifreeze, instead of forming a solid
lump of ice, what you get is more a slush, such that there is still
considerable protection from split pipes and joints eased apart.

On 08/09/2014 16:15, Dave Liquorice wrote:
On Mon, 08 Sep 2014 12:37:47 +0100, Michael Chare wrote:

Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the
winter.

So the CH doesn't freeze but other water pipes do, hum...

Think you'd be better off spending the money on a frost stat.


I am looking for a solution for a holiday house. The advantage of
antifreeze is that it will work even if the boiler fails to start.
The other pipes would have to be drained off. Estimating the volume of
the system is clearly the next problem.

In my presence house I do have a frost stat in the attic. Although this
is set very low, it does sometimes trigger in the winter when the house
is being lived in and heated. The house has to be heated quite hard to
reverse the thermostat.


--
Michael Chare

On 08/09/2014 13:00, Harold Davis wrote:
Michael Chare wrote in
o.uk:

Is it practical to put anti freeze in a domestic central heating
system to stop the water freezing if the system is left switched off
in the winter.

Yes - that's what they do in Sweden, using glycol.

Harry


Summer houses are very popular in Sweden and it gets very cold in winter.

--
Michael Chare

On 08/09/2014 17:47, Michael Chare wrote:
The other pipes would have to be drained off.

Really? No water from the mains to the boiler (or header tank if open
system). Possibly not the best way of running a system.

--
Rod

On 08 Sep 2014, Reentrant grunted:

On 08/09/2014 12:37, Michael Chare wrote:
Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the
winter.


There's nothing special about antifreeze. To a good approximation,
depression of freezing point depends *only* on the concentration of
additive, not what chemical it is.

I haven't a clue how much the freezing point can be depressed? Presumably
a goodly amount since AFAIK it can protect a car radiator against anything
the UK climate routinely throws at it; however it will be pretty
concentrated in that application.

--
David

On 09/09/2014 08:20, Lobster wrote:
I haven't a clue how much the freezing point can be depressed? Presumably
a goodly amount since AFAIK it can protect a car radiator against anything
the UK climate routinely throws at it; however it will be pretty
concentrated in that application.

In a roundabout way, I think we actually mostly do have a good idea of
that. Might well have the story garbled, but I thought Fahrenheit put
his best efforts into depressing freezing point with salt in order to
set the zero point on his scale. Hence 0 F or about -18 C.

However it appears that ethylene glycol allows the temperature to get
lower - around -40?

Not sure why this is - maybe how miscible/soluble the substances are in
water.

--
Rod

On Mon, 08 Sep 2014 12:37:47 +0100, Michael Chare
wrote:

Is it practical to put anti freeze in a domestic central heating system
to stop the water freezing if the system is left switched off in the winter.

Certainly. Use propylene glycol or even just glycerine if you know any
biodiesel makers nearby.

On Monday, September 8, 2014 12:37:47 PM UTC+1, Michael Chare wrote:
Is it practical to put anti freeze in a domestic central heating system

to stop the water freezing if the system is left switched off in the winter.





--

Michael Chare

Yes; the Yanks do it frequently.
Propylene glycol (non-toxic & maore expensive) not ethylene glycol (car anti-freeze, very toxic).

You introduce a maintenance problem, in that the glycol turns into some acidic compounds over time, in the presence of heat and oxygen (don't know the chemistry). The acidic stuff will start really aggressive corrosion of the radiators. You have to drain it & renew it before it turns bad, and monitor its pH.

Plan B is a frost thermostat.

On 15/09/2014 11:54, Onetap wrote:
On Monday, September 8, 2014 12:37:47 PM UTC+1, Michael Chare wrote:
Is it practical to put anti freeze in a domestic central heating system

to stop the water freezing if the system is left switched off in the winter.
--

Michael Chare

Yes; the Yanks do it frequently.
Propylene glycol (non-toxic & maore expensive) not ethylene glycol
(car anti-freeze, very toxic).

You introduce a maintenance problem, in that the glycol turns
into some acidic compounds over time, in the presence of heat and
oxygen (don't know the chemistry). The acidic stuff will start
really aggressive corrosion of the radiators. You have to drain
it & renew it before it turns bad, and monitor its pH.

On sealed system this isn't an issue, once the limited amount of oxygen
is used it won't get any more and the inhibitor should cope with it, or
have got first dibs on the oxygen.

With an open header tank there will always be a small amount of fresh
oxygen being dissolved in the water.


Plan B is a frost thermostat.

Or plan
C: leave the heating on with stat set to minimum. Not a good idea with a
permanent pilot as the water from combustion can corrode the heat
exchanger by condensing on the cold surface.

On Tuesday, September 9, 2014 8:33:07 AM UTC+1, polygonum wrote:

In a roundabout way, I think we actually mostly do have a good idea of
that. Might well have the story garbled, but I thought Fahrenheit put
his best efforts into depressing freezing point with salt in order to
set the zero point on his scale. Hence 0 F or about -18 C.

IIRC he defined the freezing point of brine to be 0F, which fits with what you said. He defined 100F to be the temperature of a human. He got that slightly wrong (we are 98.4F not 100F) because he based it on experiments with cows (assuming they were the same temperature as humans which they aren't).

Robert

On 01/12/2014 09:38, RobertL wrote:
On Tuesday, September 9, 2014 8:33:07 AM UTC+1, polygonum wrote:

In a roundabout way, I think we actually mostly do have a good idea of
that. Might well have the story garbled, but I thought Fahrenheit put
his best efforts into depressing freezing point with salt in order to
set the zero point on his scale. Hence 0 F or about -18 C.

IIRC he defined the freezing point of brine to be 0F, which fits with what you said. He defined 100F to be the temperature of a human. He got that slightly wrong (we are 98.4F not 100F) because he based it on experiments with cows (assuming they were the same temperature as humans which they aren't).

Robert


http://www.bbc.co.uk/programmes/b04pc2zs - about 6:25 in.

--
Reentrant

On Mon, 01 Dec 2014 08:56:13 +0000, Peter Hill wrote:

C: leave the heating on with stat set to minimum. Not a good idea with a
permanent pilot as the water from combustion can corrode the heat
exchanger by condensing on the cold surface.

What cold surface? Everything will be warmed by the permanent
pilot...

--
Cheers
Dave.

On 01/12/2014 18:20, Dave Liquorice wrote:
On Mon, 01 Dec 2014 08:56:13 +0000, Peter Hill wrote:

C: leave the heating on with stat set to minimum. Not a good idea with a
permanent pilot as the water from combustion can corrode the heat
exchanger by condensing on the cold surface.

What cold surface? Everything will be warmed by the permanent
pilot...


You may think.

I had the pleasure of cutting holes the sheet metal of the combustion
chamber and flue draught diverter to fit glass windows so the
condensation on the cast iron heat exchanger could be mapped. Where it
was and how long it took to clear.

On 01/12/2014 09:38, RobertL wrote:
On Tuesday, September 9, 2014 8:33:07 AM UTC+1, polygonum wrote:

In a roundabout way, I think we actually mostly do have a good idea of
that. Might well have the story garbled, but I thought Fahrenheit put
his best efforts into depressing freezing point with salt in order to
set the zero point on his scale. Hence 0 F or about -18 C.

IIRC he defined the freezing point of brine to be 0F, which fits with what you said. He defined 100F to be the temperature of a human. He got that slightly wrong (we are 98.4F not 100F) because he based it on experiments with cows (assuming they were the same temperature as humans which they aren't).

Robert

Isn't that a consequence of setting the zero point, setting boiling
point, and making a decision to divide the range into 180 degrees? (No
accident that is expressed in degrees. Nor that it is equivalent to two
right angles in the geometric equivalent.) You cannot get all three at
numerically "nice" points on any equal-division scale unless they fall
there.

--
Rod

replying to Peter Hill, Tony t wrote:
Just found this forum when looking up amount of Antifreeze to use. Couple of
points, first is that several commented day about frost stats which implies
heating left on but this could be more expensive than the anti freeze and less
reliable. Draining a heating system is far more complicated than most domestic
drinking water systems. Oh and one comment about no water supply to heating
system, combos must not have a fixed supply. I drained my heating this winter
as I was away for months, took a day to get it filled and heating the house
which was not good in sub zero temp. Here in Austria anti freeze is quite
normal.


--
for full context, visit https://www.homeownershub.com/uk-diy...em-993442-.htm

On Monday, 3 July 2017 21:44:04 UTC+1, Tony t wrote:
replying to Peter Hill, Tony t wrote:
Just found this forum when looking up amount of Antifreeze to use. Couple of
points, first is that several commented day about frost stats which implies
heating left on but this could be more expensive than the anti freeze and less
reliable. Draining a heating system is far more complicated than most domestic
drinking water systems. Oh and one comment about no water supply to heating
system, combos must not have a fixed supply. I drained my heating this winter
as I was away for months, took a day to get it filled and heating the house
which was not good in sub zero temp. Here in Austria anti freeze is quite
normal.

You're replying to a 2014 question. And this is not a forum. Use a sane portal to uk.d-i-y or you will be ignored by 98% of posters.


NT