Anti-freeze in CH system?

[The Natural Philosopher]

Christ. Are they?

Been a few years since I took one apart..

[Nick]

I've not heard of antifreeze being used in a CH system either (hence my post) and I suppose there are good reasons for that. One being that CH systems don't freeze under normal usage. In this case the usage is not normal. The house is generally unoccupied and the fuel supply appears to be unreliable. The system is equipped with a frost stat which is quite ineffictive if there is no fuel. I am trying to devise a solution that will be workable for my wife but also of economic value. She would not be able to drain down/refill............... see op above. Wife & I are both not far off receiving our bus passes. We both realise that this course might be detrimental to the property, however it may be in preferance to burst pipes. Unfortunately the dear old place has seen little maintenance in the past 30 years. My wife has yet to decide what she will do with the house. I suspect we may refurbish and retire there. Possibly demolish & rebuild. Thanks to you and all those that have responded to my plea. Good luck,

Nick.

[Usenet Nutter]

Aye and an equally long time since you looked at a cylinder heid ...I had Sunbeams and Avengers many many years ago ....25 probably ...and they had ally heads . :-)

[Peter Parry]

Ah, reading your later post it is much clearer, although I wouldn't have thought trying to plumb a permanent drain to the cylinder would be particularly straightforward.

It won't be particularly expensive if your neighbours are able to check the gas level say fortnightly. You could alternatively fit a GSM dialler to alert you to the electric heaters coming on (Indicating the gas heating has gone off - I assume there is no land line phone in the property). In this case they are only on until the gas supply is replenished. Will the boiler start again by itself once it has cut out for no gas?

Oil filled radiators are very safe and unlike standard radiant heaters no part of them is at a particularly high temperature They are therefore ideal for this sort of application.

Yes - set the electric thermostat so that with your CH thermostat working and fuel in the system the electric heaters will not come on. If the CH stops for any reason the temperature drops below the CH thermostat set point and the electric heaters come on. You can use that power on signal to get an alert sent to you.

[mick]

...or fit trace heating wire along the length of all the pipework that's at risk. It might be worth a thought.

This system is used in heating some schools etc. (although without putting heat into the system via an immersion heater). If the return temp continues to drop the boiler is fired up for a bit.

[Cash]

In my experience over the years of attending many flooded houses due to water leaks, the only sure way to prevent problems in unoccupied properties during the old winter frosts is to turn the water off at the outside stop-tap and drain the system down (including the cylinder if fitted), as frost stats and heating systems seem to follow "Sods Law" and have the occasional problem when least expected.

I'm in somewhat similar 'medical' circumstances myself Mick, but at my age, I sometimes say "what the hell" and just let the old Jack Daniel's tickle the back of the old throat with its rather smooth taste.

The trouble is, I'm rather partial it, and I find that when I start on the stuff, I just cannot put the bottle away until there is a rather large 'dent' in its contents - but we only live once, so a couple of times a year I give in to temptation and enjoy me-self, and besides, it takes the edge off the protestations of SWMBO! LOL

Cash

[Cash]

Peter,

There is usually a 'drain off' point in a cylinder where a drain valve can be fitted during the cylinder installation and simply fitting a length of hose pipe to this and opening the valve will do the job nicely - although there are times when this is 'left out', either because the installer is simply lazy or cannot be bothered to fit any extention pipework to get the drain-off valve around obstructions [1].

[1] In my system, due to the design of the system, the cylinder drain-off point is in an impossible position in the airing cupboard to use - so the installer fitted a couple of sections of 1/2" copper pipe around the cylinder to bring the valve into a nice, easy position to use.

BTW, I didn't read the post that you replied to as I have all google and gmail addresses 'killfiled' to prevent spam - so I may have not picked up on a point or two when responding to your post. Cash

[Owain]

And I thought modern Calor tanks had an automatic sensor that phoned home ...

off GSM, so no phone line needed.

Owain

[SS]

I had a similar problem that this forum answered for me ie empty property and I have 100 mile round trip.

I have a combi boiler so dont have tanks to worry about.

I was intending draining the system but having got down there a couple of days ago and no frozen pipes decided to turn the heating on for half hour every 6 hours so 2 hours per day at a low setting, cheaper than a burst pipe.

My next stage is to go back in a week or so as I have some work to do in it and set the heating low as per above and then switch the electric mains off (this will stop the heating kicking in) if the weather forecast is ok. If the weather looks like dropping to freezing then I have a neighbour who will simply flick the mains electric mains switch til the temp rises and then switch off if it drops.

[Andrew Gabriel]

Yes, very. So much so, that Andy Hall, who used it in the heating branch which fed his outside workshop, designed the system so he could drain it into a tank, and refill from the system from the tank again. The cost of loosing the Inhibitor-Antifreeze if you needed to drain down was simply prohibitive (you need lots of it, and it's very expensive).

[Dave Liquorice]

Why not just set the programmer to constant and the the room stat to something between 5 and 10C. It will only then heat when it needs to and only to a temp sufficient to keep the place unfrozen.

There is still a chance that a vicious cold snap with a hefty wind could cool the place rather low in 6 hours...

[Mike Harrison]

I think the key is to heat as little as possible - keeping it warm enough to stop freezing ought to use a pretty low level of gas, however you could probably make a big difference by simply covering all the rads in blankets or similar to preserve heat in the system.

Another thought is you could backup the gas supply with an electric water heater in line with the CH flow, thermostated to come on at a lower temp than the gas frost stat, and make sure the pump still runs in the absence of gas.

[Andrew Gabriel]

Like others have said, you want the system on 24/7, but at a low temperature. If you aren't there, it doesn't matter if it gets cold in middle of day or middle of night, you want exactly the same response from the heating system in either case.

From 2000 to 2005, I spent periods working out of the country and had much the same issue. In my case, I designed and installed remote monitoring of the house for things like temperature and the state of the heating system. If the boiler locks out, it rings me up. If the house goes below a certain temperature, it rings me up. Some hours before my return, I would command the system to heat the house back up to normal room temperature and generate enough hot water for a shower, etc. 10 years ago, there was nothing off-the-shelf available to do this (without going to an expensive commercial building management system, which cost more than my house was worth), which is why I designed my own system. What really surprises me is that now, 10 years later, there's still almost nothing much available to do this - I would have guessed it would be the norm by now.

Draining tank and cylinder is not difficult. Draining all the rest of the pipework can be impossible. Often large sections which duck down below floors and pop up somewhere else, either with no drain valves, or it's unlikely to be practical to go around and drain them all off every time. Then you have all the basin U-traps (which mostly will survive freezing), toilet U-traps (modern ones tend to break), etc.

[Onetap]

Anti-freeze is usually mono-propylene glycol or mono-ethylene glycol.

The anti-freeze used in domestic heating systems is usually propylene glycol. Ethylene glycol is used in most cars but is toxic in fairly small quantities and is not used where there is a risk of contamination of a potable water system, i.e., the domestic hot water.

In the presence of dissolved oxygen and heat both MEG and MPG will oxidize into numerous acidic compounds. This is bad because it makes the water a conductive electrolyte and you get rapid galvanic (aka bi- metallic) corrosion which attacks the steel radiators. It also generates oxygen & hydrogen by electrolysis, the oxygen further degrades the glycols, the process accelerates.

The usual recommendation is to change car anti-freeze every few years because of the above.

If you put anti-freeze in, I would strongly recommend you monitor the water pH. Get some litmus paper off E-bay.

The Americans put anti-freeze in heating systems more frequently ( more severe winter weather, more ownership of holiday homes) so have a search of the archives on a US heating forum, here, for example;