Hi folks,
A bit of background information before I get to my question. My little house in Deux Sevres (two floors over a basement) has an oil-fired central heating system. The radiators are those old cast iron ones which I like very much. The boiler is in the basement (as is my electric hot water ‘ballon’). The CH pipes (and the hot water supply pipes) are run around the perimeter of the basement with branches rising to the radiators on the two floors above. None of the pipework is insulated.
The first thing I am going to do is insulate all the pipes as I don’t want to heat the basement via heat loss through uninsulated pipes. I will also insulate the cold water supply in case the risk of freezing increases as a result. I’ve ordered lagging jacket for the ‘ballon’ too.
And now, to my question: I live in a hard water area. I was wondering if I am likely to be losing efficiency in the radiators and/ or pipes due to limescale? Is it worth adding a ‘détartant’ or similar product into the system via a radiator? I know I could google this but I’m interested in hearing about the experience of someone who’s done something similar.
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Hola.
Perfect project I would say.
Adding a scale inhibitors is a good idea and (you will know this I’m sure)..you will need a special pump to get the stuff into your system. Don’t know if your pipes are steel or copper but in UK, Fenox (Fernox?) make some stuff and I’m sure theres something similar here.
The pipe insulation is fun and there’s a bit of skill to it and (again you probably know), make sure the pipe lagging is bound and taped. Some more commercial lagging comes with a tear off adhesive strip. It’s ok and that together with some proprietary tape goes a long way. Cables ties are v useful too.
Finally, once all done it’s a good idea to check in on it once a year to see if anything has fallen off and or been chewed on by critters.
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Any idea when the system was last cleaned? You soon know if you start to drain a little water from it and comes out like gravy.
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If it’s a modern water tank it’s well enough insulated - they’re not like the old copper ones.
But yes insulate the pipes.
As to the radiators. If it’s an older system look at getting it power flushed (plumber) - was 200’ish but that’s a 10 year old price. That will get it properly clean.
You can get cleaning products that help clear it (usually put in leave for a week or two then flush). Then add the inhibitor - but it’s always worth having inhibitor in the system. There’s Sentinel 500 which is both inhibitor and antifreeze which doesn’t harm if there’s pipes in the cellar
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Hello Mike,
It sounds as though your heating system is virtually identical to mine, just across the border into Vendée.
I think that the first thing to acknowledge is that she is probably quite an old lady, and therefore needs to be treated gently and with appropriate respect
for her age. Certainly our system was originally coal fired and has quite a lot of 2 inch diameter steel pipework as originally it was a system that worked purely on convection circulation (no pump).
I suspect that as you have the cast iron radiators, that you probably have quite a lot of the original steel pipework as well.
Certainly, insulating the pipework in the cellar will be a very good thing to do, but before you do so may I suggest that armed with a good flashlight, you make a detailed inspection of said pipework regarding any weeping or leaks. Look for brown rust staining running along the pipes, or indeed brown rusty patches on the walls and floor below the pipes. Use a mirror so that you can see the back side of the pipes where they run close to a wall or ceiling. Ascertain whether the system holds its pressure, as if you are having to regularly top up the pressure it would be indicative of a little leak somewhere.
Using an anti-corrosion additive (such as Sentinel X100 which is commonly available in France) is a good idea, but don’t use too much. These additives (especially the cleaning ones), can be somewhat ‘searching’ by their nature, and will reveal a small leak by turning into a bigger one.
If the system works, then at this time of year I recommend leaving it alone apart from the insulation. Flushing out the gunge in the rads is something best done in the warmer months.
As others have said, the cleaning can be done professionally, but there is also a DIY solution which is less costly. With the modern lightweight steel rads it is fairly simple to dismount them and take them outside for a good flush through in both directions with a hosepipe. Our good old fashioned radiators are a totally different kettle of fish due to their weight. I can move our larger ones about 2 inches, one end at a time, because they are incredibly heavy even when empty.
So what I do is drain the system, disconnect the radiators, walk them sideways just enough to free the connection points from the pipework, and then use some made up lengths of flexible pipe to connect one of the entry / exit ports to a hosepipe and the other to a length of pipe that goes out of the window. Turn on the hosepipe and flush away. (Do be careful about where the waste water ends up as it will instantly and indelibly stain anything with which it comes into contact – walls, paving, people etc.) Once you have flushed it clean in both directions the rad can then be walked back into position and reconnected. It really is a good idea to have a muscular helper on hand for the bigger rads.
I tend to shy away from using cleaning chemicals as they can be a bit of a shock to which the old lady will not take kindly. Just flush with clean water and then add the anti-corrosion mixture once you have ascertained that there are no leaks after re-assembly of the system. The anti-corrosion will also lubricate the circulating pump and thus prolong its life.
On a general note, and because the system has age to it, I keep the temperature of the water exiting the boiler down to around 60 degrees, and also limit the operating pressure to 1 bar to prevent ageing joints from developing leaks. I know that some folks will advocate higher numbers than these but I find that it is actually cheaper to run the system for longer each day at a lower temperature than to have it full blast for shorter periods. It’s a bit like the fuel consumption on a car where a steady 55mph works out better than lots of stop / start operation.
In this cold weather our system runs 24hrs per day and I just turn the room thermostat down a bit at night.
As I said, the system is an old lady. Treat her gently and she will serve you well for many years to come.
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Thanks @MikeyPotts @Corona @chrisell and @Robert_Hodge for your replies.
A couple of things that came back to mind, prompted by your comments - Firstly, I don’t think the system has been properly flushed in years however, it was drained down when I had a radiator moved in the kitchen and so was refilled (rather than power flushed) last year. When I bled the radiators recently, the water looked clean enough; Secondly, I remembered that a piece of pipe that the plumber removed was still in the shed so I checked on that, it is copper and clean inside with no noticeable buildup on lime. Edited to add, why I didn’t think of this before . . Sometimes I think I have a ‘touch’ of Alzheimer’s . . .
Robert, you have described the CH system in my house uncannily well. I will follow your advice.
Thanks all once again. Hoping your heating systems are keeping you toasty as we endure this cold spell 
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Yes as it’s not really the time of year for undoing your heating, stick to the pipe insulation for and leave anything else for summer. Don’t see many if any magnetic traps on systems in France, baring in mind the number of iron radiators.
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