How often to add inhibotaor?

diystarter7

Hi

If the CH is working puka, ie no leaks etc and no need to let out air, fill with water several times a year, I've read its wise to renew 
the inhibitor every 12 months

We have never really done that and no magnetic thing - but did get some designer rads repalced several months ago and new one was added

Is there a brand/type that lasts longer is there are no leaks etc. We have used the corgi one (I'm aware the anti-freeze  rust inhibitor in some cars like mine is so-called, 'for life but not sure about that but both cars regularly serviced and they've never done the antifreeze on car)

So is there something like above for cars? I'm aware we have had something called Fenollio or something like that in the past as plumbers used to swear by it

Thanks if you can help.

ThisIsWeird

'Fernox'? Their products used to be the default choice, but there are many to choose from, and afaik all perform well.

On a sealed system like yours, a 'dose' should last pretty much for 'life'. Almost certainly at some point, the system will need draining down, and then fresh inhib should be added. Also if it needs topping up at regular intervals, and depending on how much.

Personally, I'd only be 'happy' if I had a magnetic filter fitted. This is the best way, I think, to monitor the health of your system - a glance at the magnet will tell you if there's any sludge, which would equal corrosion. The also make adding fresh inhibitor or other products a breeze - I wonder if yours would benefit from a dose of sealer, for instance?

So, if you can, fit a filter. If not, then you'll likely have to fully close off a rad, partially drain it down, and inject in concentrated inhib via a bleed screw. 

ThisIsWeird

Products? There's Sentinel, Adey, and plenty others, as well as Fernox. I have no preference.

diystarter7

Hi
Thanks.
Sorry for being a silly sausage but the ones you mention can they last longer?

Re the magnet thing, I 100% agree with you but the combi is fitted into a bespoke kitchen cupbard and between that and the granite work surface the pipes are almost flush agains the wall and tiled in a sslim uint. The cupboards below that, it would mean cutting out the backing board which is an integral part of the cupboards and I have considered this but dont want to see the kitchen trashed - but these magnet things are ace and you have to fit them to get a longer warranty on some boilers.

Thnaks you again for you detailed help.

ThisIsWeird

All the inhib makes, afaik, will last the same - essentially for 'life'. Unless you have constant water loss and lots of top-ups.

In a 'perfect' system with no issues, it'll only need replacing when the boiler goes kaput - around 15 years? 

Having said that, it is 'recommrnded' that concentration levels are tested annually as the chemicals 'break down' How many folk do that?! Not me.

In practice, most CH systems will require some attention every few years - a change of rad, a boiler part being replaced - and fresh inhib should be added each time.

FaceHead

Most manafacturers seem to say that inhibitor breaks down, and needs a top up (say half the initial quantity) every couple of years. 

Most people, I think, don't do this with no I'll effects. Presumably the idea that you need to too it up is just a way to get repeat custom, and I agree with the consensus here that it's for life unless you drain it away. 

diystarter7

Thanks.....

plumb1_2

Inhibitors do degrade over time always best to top up every couple of years, you can buy small test kit Sentinel.
You can buy anti freeze for heating systems, recommend . SF sell it.
you can buy inhibitor in liquid form or concentrate ( like a mastic tube).  I use a injection bottle.
either put in in heater tank, or magnaclean type, or radiator, but you need to drain off some water.

diystarter7

Thank you all - wll see how much the test kit is and may get one for next year.
Thanks all