VFM CH antifreeze / inhibitor?

Hi All,
Mums old ex gravity (now fully pumped) indirect CH system has been drained and re-filled (hopefully) for the last time for a while and I am concerned about making sure it doesn't freeze up if she's away or a few days etc?
The rads are smallish and cast iron and the boiler a low capacity copper HE.
There is no frost setting on the boiler nor room stats etc. It's a very basic system but it works for Mum and she's happy with it for now. ;-)
So, I'm not sure if I should run some de-scaler though it (we de-scaled the HE on it's own a while back) first or because of the diameter of all the pipes (1-1/2" down to 22mm) that it's not worth it?
So, alongside that, is there any good VFM 'stuff' to cover both the cleaning and the inhibiting / antifreeze anyone would recommend please?
Cheers, T i m
p.s. For pipes from the water tank in the loft ... would plastic be better than copper re frost resistance?
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You can buy stuff from "Fernox" does the job. In days of yore it was unnecessary, it only became necessary when balanced draught/room sealed boiler came into use. ie the heat exchanger is exposed to frost.
Pipework should be insulated, this guards against frost as well as heat loss.
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On Wed, 14 Nov 2012 07:46:44 -0800, harry wrote:

Yes, I know but I believe it's not necessarily the best VFM on the market?

Ah, good point.

'Guards against' rather than 'guarantees against' I notice. ;-)
I've had a bib tap pushed off a standpipe in the kitchen I was doing up and that was indoors (luckily the water was still frozen when I got to it!) so I'm very aware of what can happen to even insulated pipes if the going gets tough enough.
I was also thinking on the idea that hot water freezes quicker than cold water (it does doesn't it) so if she turns the CH off for a long period (even for a weekend say) and it all gets very cold in the loft / boiler ...
Cheers, T i m
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Turn the thermostat down to about 5 degrees and leave the system on timed. Works for us.
Chris
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On Wed, 14 Nov 2012 08:41:58 -0800 (PST), Chris Holmes wrote:

What don't you understand about "There is no frost setting on the boiler nor room stats etc."?
Think I'd fit a frost stat some where and let the boiler fire up if it needs to.
--
Cheers
Dave.




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On Wed, 14 Nov 2012 18:00:17 +0000, Dave Liquorice wrote:

Now *that's* a good idea. ;-)
So, given this system has only a plug in 24hr timeswitch and the boilerstat, I'm guessing the frost stat would have to be wired in parallel with the timeswitch?
Cheers, T i m
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On Wed, 14 Nov 2012 12:57:22 -0600, T i m wrote:

"Plugin" as in 13A type plugin or plugin as a module that plugs into the boiler?

Yes, a frost stat needs a permenant live so that it can fire the boiler without the time switch being on. Be careful to ensure that this permenant live is taken *after* the boiler/heating system isolation device.
Depending on your boiler it might be a simple addition back to the wiring block in the boiler. Plumbers aren't the brightest sparks in the box, so makers attempt to keep the wiring requirements simple.
--
Cheers
Dave.




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On Thu, 15 Nov 2012 09:29:59 +0000 (GMT), "Dave Liquorice"

The former. Like I said, this is a very simple system that was 'upgraded' from a full gravity coal-fired jobby some years ago. Mains socket in the airing cupboard, plug in time switch, 13A plug top with cable going down to boiler below. No, sorry, double adaptor in time switch, one cable going to boiler, other to the pump right beside the time switch.
As crude and basic as all that sounds, it's worked faultlessly [1] for a very long time and the fact that stuff is just plugged in means you can very easily faultfinding, *fully* isolate and run things independently without fear of the wrong things cutting in (like running the pump without the boiler to help clear a freshly filled system of air).

Understood (so that's the main 13A plug them). ;-)

Understood. ;-)
However, as you can probably see from the setup I've described above, it wouldn't be so easy to do there.
Do I take it these frost stats are normally located in the boiler itself because of the possibility of the 'exposed to the outside air' HE becoming frozen (as Harry mentioned)?
Cheers, T i m
p.s. Again, these system has survived probably in excess of 30 years *without* a frost stat so maybe it's just a matter of getting some decent antifreeze / inhibitor again. The stuff we drained out had been there for many many years and was blue like car antifreeze?
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On Wed, 14 Nov 2012 08:41:58 -0800, Chris Holmes wrote:

The only 'stat' is the boiler stat itself and she's normally only got that on No 1 or 2 (out of 10)?
I think the (plug_in) timer is set to enable the boiler twice a day for about an hour at a time.
She basically 'lives' in the lounge and that has a pretty powerful gas fire and puts her electric blanket on before she goes to bed. ;-)
Cheers, T i m
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I think you need a serious upgrade of the system. It must be costing a fortune to run. The froststat would indeed need to be wired in parallel with the time switch. The problem is, where to locate the stat itself. If she has a gas fire, get a carbon monoxide alarm for her.
BTW, water that has been heated (so driving out dissolved gases) freezes at a higher temperature than water that has not is more accurate.
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On Thu, 15 Nov 2012 00:01:12 -0800 (PST), harry

I think you have to factor all things in when you consider such things though. Like, the boiler cost her little (second hand) many many years ago and has cost next to nothing to maintain for all that time?
The (semi detached) house is made with solid brick walls so heating the house fully would be expensive.
She isn't there all the time (she often stays with my sister and goes away on trips etc).
She is 'old skool' and knows to put a jumper on and has never complained about anything like being cold.
FWIW, we are in a similar position here with a 3 bed Victorian EOT (solid 9" brick wall) cottage with no central heating and just a mix of E7 slimline / automatic storage rads, open and balanced flue gas heaters. A fan / radiant heater can be put to use if required but we don't have any heat on in this lounge now and the Mrs and I are sitting here in basically our PJ's (late night last night <g>) and no one has mentioned the cold. ;-)
We haven't turned the storage rads on in the bedroom 'yet' this year and have had no other form of heating up there either. However, we are fully double glazed and have reasonable insulation in the loft (at least).
I am very very happy not to have any water in the house at a higher level than our Multipoint water heater. ;-)

Understood. I'm guessing if it were in the kitchen, near the boiler and even set to say 5DegC or some such, that might be better than nothing?

She has and good point. (We have one here as we have an open gas fire).

Ah, thanks for the clarification. ;-)
Cheers, T i m
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BTW if the pipework in the loft does freeze, the cast iron radiators could crack on firing up if no safety valve is fitted to the system.
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On Wed, 14 Nov 2012 07:49:17 -0800 (PST), harry

There is a safety valve, just on the flow over the boiler.
I was wondering if it would be ok to use std car antifreeze on the CH system? I mean, it's designed for cast iron (cylinder blocks) and copper (old rads?), to stop water freezing when it gets below 0 degC (or worse) out there and designed to run at over boiling point (pressurised system but this is open so runs much colder than a car)?
Or would the CH stuff be better / cheaper?
Cheers, T i m
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Well it's not recommended. I have done it in my solar panels. It seems to be OK, been running for three years. I think there is an alleged problem if there is any possibility of it getting into the domestic hot water. (It is poisonous). But then I don't drink that water even if it did. (Heat exchanger in hot water cylinder leaks?)
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On Thu, 15 Nov 2012 00:06:55 -0800, harry wrote:

Ok.
Understood. So are you saying that the stuff specifically designed for CH use isn't poisonous?
Cheers, T i m
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Apparently not AS poisonous. It comes under "urban legend" really.
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On Thu, 15 Nov 2012 23:38:54 -0800 (PST), harry

Ok and thanks.
So, any thoughts re a value for money antifreeze / inhibitor please? I know of brands like Fernox (Alphi-11?) and Sentinel (X500?) but wondered if the sheds might have their own brands that could be as good for less?
Or if there was a brew-your-own cheaper like when you use vinegar or lemon juice for cleaning purposes?
And what about the risks to pipes and joints in hi-risk freezing areas like the supplies to / from the tanks in the loft?
Are soldered joints more resistant to being 'pushed open' than compression ... does plastic / 'Speedfit' resist damage (because it can 'give'?) better than copper?
Cheers, T i m
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Propylene glycol - dead cheap by the gallon.
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On Fri, 16 Nov 2012 22:16:58 +0000, Grimly Curmudgeon

Something like this you mean?
http://www.farmacy.co.uk/products/440-propylene-glycol-5l http://mistralni.co.uk/products/inhibited-propylene-glycol
Or are there other uses where it's sold cheaper?
Cheers, T i m
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I'm sure I've seen non-food grade sell for a tenner a gallon recently. I don't recall where, though; as I was looking for the food-grade.
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