# CH corrosion inhibitor



## SpokeyDokey (2 Oct 2022)

Adding corrosion inhibitor to CH system. 

Last time I did this I partially drained the system and added corrosion inhibitor via the expansion tank.

Do I really have to drain the system at all to add it?

Can I just take a volume if water, equivalent to the fresh inhibitor that I am going to add, out of the tank and add it that way?

Am I wrong to assume that it will eventually work its was around the entire system from there?

Ta in advance.


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## slowmotion (2 Oct 2022)

It could take a long time for the contents of the F & E tank to work it's way into the circulating part of the CH system. You can get inhibitor dispensers that inject the stuff via a radiator. That means that it gets straight into the circulating water.


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## mistyoptic (2 Oct 2022)

I thinnk "eventually" is the operative word. If you want it in the system now and doing something, you'll need to be a bit more "hands on"


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## CXRAndy (4 Oct 2022)

If a radiator has an air gap, depressurise the system, add it via bleed valve, assuming you can find a feed tube. 

The boiler, should have some port


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## mistyoptic (4 Oct 2022)

CXRAndy said:


> If a radiator has an air gap, depressurise the system, add it via bleed valve, assuming you can find a feed tube.
> 
> The boiler, should have some port


I'm all in favour of having some Port but I'm not wasting it on the boiler


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## slowmotion (4 Oct 2022)

CXRAndy said:


> If a radiator has an air gap, depressurise the system, add it via bleed valve, assuming you can find a feed tube.
> 
> The boiler, should have some port



If the system has a feed and expansion tank, it won't be pressurised.


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## SpokeyDokey (4 Oct 2022)

Guess I will have to shut off the ball cock and drain the system a bit.

PITA - thought I could cheat! 😁


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## slowmotion (4 Oct 2022)

If you don't want to climb into the loft, you could try some Sentinel X100 Rapid Dose, introduced by a radiator.......

https://www.sentinelprotects.com/uk/rapiddose

Screwfix has it.


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## Phaeton (4 Oct 2022)

Putting it in the tank won't/shouldn't work unless you have a leak, however you could potentially put it into the tank then draw water out of the system to pull water out of the tank.


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## slowmotion (4 Oct 2022)

Phaeton said:


> Putting it in the tank won't/shouldn't work unless you have a leak, however you could potentially put it into the tank then draw water out of the system to pull water out of the tank.



Good idea. Tie up the ball valve of the F&E tank, stick in the inhibitor, then go down to the lowest point on the system and drain out a volume of water slightly greater than the volume of the tank. Then untie the ball valve.


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## fossyant (4 Oct 2022)

I add to tank. If you want it in sooner, add to tank, then draw out a few buckets of fluid from a bleed port on a downstairs radiator. I've just been bleeding one of our ports to get rid of the dirty fluid before I top up again with inhibitor. I've never tried directly via a radiator.


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## SpokeyDokey (4 Oct 2022)

fossyant said:


> I add to tank. If you want it in sooner, add to tank, then draw out a few buckets of fluid from a bleed port on a downstairs radiator. I've just been bleeding one of our ports to get rid of the dirty fluid before I top up again with inhibitor. I've never tried directly via a radiator.



I have a bleed port ithen garage which is underneath the house so I'm going to do tbat.

I'll kill the ball valve first.

Loft is fully boarded and illuminated so it'll be no hassle.


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