I've just had a complete new system installed (Baxi 105e combi, 10 rads and TRVs on all bar bathroom rad) but the installer has not put any inhibitor in the system. The Baxi manual says that a suitable inhibitor should be used and failure to do so "may invalidate the warranty". The installer says that:
a) it's a sealed system so no air can get in to cause any corrosion b) I live in a soft water area so the water is "non-agressive" anyway (presumably referring to scale build up as opposed to corrosion?) c) there's a school of thought that says that inhibitors can "cause more harm than good"
and
d) he hasn't got any inhibitor in his own home system either!
So, do I take his advice and leave well alone or go and get one of those Fernox "injector" tubes of inhibitor and apply it myself?
Absolutely, definitely, with no doubt whatsoever, ensure that you install inhibitor. He is a moron, or is just looking towards his long term income from replacing all your radiators in three years time.
There will already be some in there and corrosion can take place anaerobically as well.
Scale build up is a hard water phenomenon and won't happen in any heating system, sealed or not as long as there are not leaks which cause new water to be added. Once any calcium and magnesium salts are deposited, that's it. Some soft water is mildly acidic, however.
The one that he and his mates (plumbers all call each other 'mate' - it's a requirement) attend at the plumber's merchants every morning as they buy their materials for the day and swap old wives tales and how they can make more money by having to replace radiators.
He can buy his radiators at trade prices.
You can usefully add the contents of one of these as the cheapest insurance policy that you can buy. In fact it's not insurance, but return on investment.. If you are going to do this properly, the water should be tested each year and more inhibitor added if necessary. Typically this will be every 2-3 years.
The gel stuff works well, but I would recommend not using the instructions on the box where it tells you to inject against the pressure. This can get messy, A better solution is to pick a large radiator and turn off both valves, noting the position of the lock shield valve. Place a vessel under one radiator valve union and carefully undo it to drain out 2-3 litres of water. Careful because if the water is rusty, it will stain. Add the contents of the tube through the injector refit the vent and open the valves. Run the heating for a while and then bleed this radiator.
I should mention that before doing this that it would be a very good idea to flush the system. If the installer doesn't believe in inhibitor he probably didn't bother to do that either. There could well be acidic flux residue in there. All you need to do is to drain and flush the system through using the filling loop. Fernox make a gel flushing agent called Superfloc which you can then add as above. Run this with the system hot for a few hours and then drain and flush thoroughly. Add water and inhibitor.
All good lies have an element of truth... but anaerobic corrosion where the Iron rads combine with oxygen in the water an produce hydrogen gas and sludge may still take place.
So limescale's not an issue but the water will be even more liekly to casue anaerobic corrosion
Means either: a) Why you want to hit me for a few quid on the is fixed price job. b) I meant to get some in but I better make an excuse rather than admit my mistake.
= a) It takes a long time to eat through the radiators some why bother, I'm going to flog the place anyway. b) He really beleives his own lies.
See FAQ. Note all the helpful comments about using the diabolical gel injection method.
Interesting that the CORGI guy who I used to test & then issue safety certifaicate for my new place, also NEVER, EVER installs inhibitor.
He thinks it is a total waste of money, just a con by the like of Fernox. This is not a way of incresing his income as I did the install myself, and he didn't charge for the saftey inspectionm & certificate issue (friend of the family)
I have a Thermal store, pressurised ... with underfloor heating, I did install inhibitor in the boiler primary circuit, and in the UFH cicuit.
Putting the inhibitor in the primaries had me stumped for a while ... how the hell could I put it it in? unlike the injector cartridge for the UFH, the boiler cct was a litre of liquid ..... luckily found a way ... unscrewed the auto air-vent on the top of the store and poured it in the store.
I'd like to hear from anyone who has used inhibitor and kept it up to strength who's had their rads corrode through - I'm not talking about outside surface rust.
And all cars these days insist you use inhibitor in the cooling system. You ignore this at your peril.
In my experience soft water was more of a problem... I bought an 8 year old house in a very soft water area. Shortly after moving in I found most of the rads were weeping at the back where they were spot welded and had to replace them..
Inhibitor in a sealed system is required because of the dissimilar metal used in the system, ferrous being the biggest offender. If the system has no ferrous, you can get away without using inhibitor. I know of some systems in soft water areas which have copper skirting heaters, copper heat exchanger boilers, bronze pump, etc, and they are fine after 30 years. I know of one system in a soft water area using a Glow Worm Spacesaver, rads, F&E tank, etc, which has been going for 24 years with no inhibitor, and all original equipment except in its 3rd pump.
Many thanks for all the advice, given me food for thought. I'll apply inhibitor, taking extra care with the "gel stuff" as advised.
Presumably applying it approx 8 weeks after system first in use is OK?
I suppose I should have got wise to this guy earlier - during the work things that you might have reasonably assumed would be included (given we were paying over the going rate) seemed to become a chargeable "extra".
Are you sure that the system was properly flushed? If not, then I would also invest in some Fernox Superfloc gel as well and put that in first. Run it hot for a few hours and then drain and flush. Put in the inhibitor and fill.
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