How long can you leave a clean CH System without inhibitor in it?

[eveares]

So I am having one of my rooms tanked and re-plastered as it has had severe damp issues.

Well about two weeks ago I fitted a SpiroTech MB3 Magnetic filter to my boiler (Vaillant EcoTec Plus 937) along with chemically cleaning the system followed by draining, refilling and then adding inhibitor to the system.

Well today the plasters removed the radiator in the room what is being re-done as they needed to tank behind it and somehow in the process managed to drain nearly if not the whole system! I of course did not see how they took the radiator off as I was doing other things.

I then of course had to refill and then bleed my Central Heating System of air.

How long can I leave the system without any inhibitor in it?

Regards: Elliott

 

[Madrab]

I wouldn't leave it any time at all without inhibitor. Corrosion will start straight away, it's only 20mins and a bottle of inhibitor to fix?? No brainer really.

As a separate note, why are you tanking, not better to correct what is causing the damp in the first place? All tanking will do is stop it coming through that internal wall covering, it won't actually stop any external damage.

 

[Agile]

You can leave it for ever.

In most of Europe they just clean their systems and don't use inhibitor.

Its a bit of a UK thing. Mostly for when the system is first installed new. After that adding inhibitor has a lesser effect.

My guess is that hardly 30% of systems in the UK have much inhibitor left in them.

Tony

 

[eveares]

As a separate note, why are you tanking, not better to correct what is causing the damp in the first place? All tanking will do is stop it coming through that internal wall covering, it won't actually stop any external damage.

About 2 years ago we had an major extension, but the existing damp issues in the very front room of the house were not addressed. The outside walls were re-renderd, but the internal walls in the front room were not touched back then. The base of the walls were drilled and then injected with some sort of damp course a few months back, and now the next step if I am correct is to have it tanked internally and then plaster boarded and then skimmed. To be honest, my mum has been dealing with all of it and so don't exactly know what is being used.

I wouldn't leave it any time at all without inhibitor

&

You can leave it for ever.

Well that helps.....Not. I guess I will just put inhibitor back in the system once the radiator has been refitted in a about a months time.

 

[Madrab]

Oxygenated water from topping up & mixed metal electrolytic/galvanic corrosion will all take place in a CH system with only plain water, adding a chemical inhibitor will slow that process down. In hard water areas, it can also reduce limescale build up.

 

[Steelmasons]

Not sure how we coped years ago with the absence of inhibitors.........systems were and still are spotless when installed correctly.

 

[Mikefromlondon]

I will agree that it is a gimmick, yes it does slow corrosion, as that is what it is suppose to do, but only helps those systems where corrosion can be a problem in the first instant, open vented systems where oxygen can enter the system 24/7
or where old system had accumulated dirt and sludge and not power flushed and a new boiler was installed.

I have a sealed CH system that has been running from 1975 until now, and has never been drained in its life, same old double rads, none have rusted, and at one time we even had to top up daily when my expansion vessel had a leak, didn't replace it but added another outside the boiler, and having said this I will eat my mouth if I lied,

Also in another house where a new CH was installed, it was never drained after initial running and 10 years later it is still running fine and water is clear as bell.

The only time any water had been drained in those many years was in 1994 when we replaced the old sine 18 with the new VCW221GB, (Vaillant) and I can even drink water from it, it is so clear and if I put water taken out of the overflow valve, and put it in a drinking glass side by side with fresh tap water, you will have a job telling which is which. Yes to prove my point I took one sip from that glass, and survived.

I do not think my sealed system needs any inhibitor, oxygen from it vapourised years ago, lack of oxygen and acids means no corrosion, the ph level being neutral as I once checked it with a strip I use for checking ph level of my fish tank.

But I have seen systems so filthy, mostly open vented ones, where you have the sludge, metal filings, and rads that have started to leak through rust on houses that were build less than 20 years ago.

So in no way I am saying you don't need inhibitor, but it certainly won't hurt your system especially if it is open vented and tank in the loft not properly covered.
But it ain't going to do anything for a while if you haven't got it in full strength.

Boilers using aluminum parts should have it, same as car engines with aluminium CH (cylinder head) need inhibitors or it will face an early HG failure.

 

[Fire and Ice]

You can leave it for ever.

In most of Europe they just clean their systems and don't use inhibitor.

Its a bit of a UK thing. Mostly for when the system is first installed new. After that adding inhibitor has a lerrer effect.

My guess is that hardly 30% of systems in the UK have much inhibitor left in them.

Tony

So having mild steel, brass, copper and possibly aluminium or stainless steel all linked with an electrolyte has no bearing at all Tony? Do you remember the days when the motor industry first started to use aluminium cylinder heads on cast iron engine blocks and we all thought that it was a marketing ploy to try to sell us summer coolant rather than just plain water ? Do you remember how the heads would corrode without it?

Rust from the insides of the rads will form almost immediately and will colour the water until the oxygen in the water is used, corrosion of the aluminium will take longer. A few days won't matter much

 

[Agile]

So having mild steel, brass, copper and possibly aluminium or stainless steel all linked with an electrolyte has no bearing at all Tony?

Pure water is a non conducting compound.

Its only when salts are dissolved in it that it becomes a conducting electrolyte.

But aluminium is a very reactive metal and certainly any system with ali components is safer with a good inhibitor.

But the OP's boiler does not use ali parts and ali rads are not at all common in the UK. Although I have seen quite a lot used in France.

Tony

 

[Fire and Ice]

Tony, do you fill your systems with pure water or do you use what the rest of us use... Tap water?

 

[Aquaheat]

I use softened water. It's expensive to do so it must be good.

 

[Aquaheat]

@eveares It'll be fine for a bit. Do what you need to do and when it's ready flush the system. (cold flush is fine no powerflushing) refill and add inhibitor. Job done. Too much over thinking in here as Ste... @Gaswizard says many many many systems have coped more years than I could remember and possibly more than he could too without it. Have a cup of tea and forget about it you'll be fine Elliot.

Jon.