pH level too high in central heating system

[wwwebber]

Hi all,

I had some large cast iron rads installed a couple of years ago. I know they are very sensitive to corrosion etc and so I ensured that the system was treated with plenty of inhibitor.

Just to make sure all is well I have tested the system and the pH has come out at 9 which is too high. How can I reduce the pH level whilst not reducing it too much. A pH of 7.5 thru 8 is apparently ideal.

Thank you.

 

[Nozzle]

Provided you have a way to measure a sample each time, then add a little acid. Vinegar, lemon juice, maybe brick acid. The stronger it is, the less you need. Why is 9 too high though? It's not that far off pH neutral.

Thoroughly circulate before adding more. Plus know that a change in temperature also leads in a change in measured pH. So do you want it pH neutral when cold or hot...

Nozzle

 

[wwwebber]

From the website :-

No caustic/corrosive/acidic plumbing compounds or liquids are to be used on or in any part of our radiators, our valves or connections including aggressive flushing agents. If required, the system should be flushed with clean water only. The water in the system must be neutralised correctly following the use of any compounds etc if required using appropriate crystals or similar. If caustic and/or corrosive compounds (liquid or other) have been introduced into the system resulting in subsequent damage to seals/gaskets, any guarantee offered will be invalid. When a chemical cleanser is used it must be thoroughly flushed from the system. We recommend the use of Fernox F5 for power flushing and F1 rust inhibitor. Unlike other chemicals these products are not acid based and should not affect seals. After treatments the water should be checked for a neutral PH between 7 – 8. System design, flushing and dosing must be in accordance with BS 5449, 1990, BS EN 12828:2003 and BS 7593.

Following this procedure the system must be closed with a sufficient corrosion inhibitor suitable for the water quantity in your system. Dosing tools should be used to ensure the minimum correct levels of inhibitor are present at all times to prevent corrosion and should take into account the particular metals within the system. Appropriate inhibitor should be used in conjunction with manufacturer’s instructions and appropriate quantities must be used for the water content of the system.

 

[wwwebber]

Also, see response below when I contacted them :-

Hi Mark, Industry standards vary slightly from one company to another, but as a guide, it is recommended that the system water should be maintained between a pH of min 6.5 & 8.5 max to prevent system corrosion. Each whole pH value below or above 7 (Drinking water) is ten times more acidic/alkaline than the next whole value. For example, a pH of 4 is ten times more acidic than a pH of 5 and 100 times (10 times 10) more acidic than a pH of 6. The same holds true for pH values above 7. For remedies to adjust the pH levels, it is worth speaking to your heating engineer for specific advice once they have fully assessed the make up of your heating system components.

 

[fixitflav]

From the website :-

No caustic/corrosive/acidic plumbing compounds or liquids are to be used on or in any part of our radiators, our valves or connections including aggressive flushing agents. If required, the system should be flushed with clean water only. The water in the system must be neutralised correctly following the use of any compounds etc if required using appropriate crystals or similar. If caustic and/or corrosive compounds (liquid or other) have been introduced into the system resulting in subsequent damage to seals/gaskets, any guarantee offered will be invalid. When a chemical cleanser is used it must be thoroughly flushed from the system. We recommend the use of Fernox F5 for power flushing and F1 rust inhibitor. Unlike other chemicals these products are not acid based and should not affect seals. After treatments the water should be checked for a neutral PH between 7 – 8. System design, flushing and dosing must be in accordance with BS 5449, 1990, BS EN 12828:2003 and BS 7593.

Following this procedure the system must be closed with a sufficient corrosion inhibitor suitable for the water quantity in your system. Dosing tools should be used to ensure the minimum correct levels of inhibitor are present at all times to prevent corrosion and should take into account the particular metals within the system. Appropriate inhibitor should be used in conjunction with manufacturer’s instructions and appropriate quantities must be used for the water content of the system.

Was Fernox F1 used? If it was, how do you think the pH reached 9? Are you sure the pH measurement is accurate? Did you use pH paper or a probe? You might be worrying unnecessarily, most metals, including cast iron, are more at risk from low than high pH.

 

[wwwebber]

Was Fernox F1 used? If it was, how do you think the pH reached 9? Are you sure the pH measurement is accurate? Did you use pH paper or a probe? You might be worrying unnecessarily, most metals, including cast iron, are more at risk from low than high pH.

Fernox MB-1 originally (same as F1 apparently) and then topped up with Adey MC1 last year, I understand that the system needs topping up regularly. I have been testing with some litmus paper.

The reason I am concerned is that on some of the cast iron rads I have noticed a small amount crusty discharge / deposit around some of the seals which worried me which is why I have been investigating this. These rads cost us a small fortune and replacing any of them is not an option at the moment.

 

[Nozzle]

The system doesn't need topping up regularly. It needs testing 'regularly' and if the test shows it needs topping up then you have to ask where the dilution is coming from. Do you have a head tank or a filling loop?

Nozzle

 

[shambolic]

Provided you have a way to measure a sample each time, then add a little acid. Vinegar, lemon juice, maybe brick acid. The stronger it is, the less you need. Why is 9 too high though? It's not that far off pH neutral.

Thoroughly circulate before adding more. Plus know that a change in temperature also leads in a change in measured pH. So do you want it pH neutral when cold or hot...

Nozzle

You daft?

 

[vulcancontinental]

Fernox has a ph buffer, it'll reduce coke to neutral.

Inhibitors do not lose effectiveness unless diluted.

If seals are leaking it's the seal not the rad.

I used to find an anti-freeze if used on a job would affect washers and glands.

I don't like to mix brands.

Don't overthink things.

 

[Nozzle]

The OP asked about changing the pH in the system, I gave a valid reply. I also challenged why the OP thinks it needs changing in the first place, also a valid challenge.

Taint nothing daft about that.

Nozzle

 

[shambolic]

The OP asked about changing the pH in the system, I gave a valid reply. I also challenged why the OP thinks it needs changing in the first place, also a valid challenge.

Taint nothing daft about that.

Nozzle

Brick Acid!!

 

[Nozzle]

Brick Acid!!

"The stronger it is, the less you need".

Hell, go the whole hog and use milkshake!

 

[ianmcd]

"The stronger it is, the less you need".

Hell, go the whole hog and use milkshake!

or dont use a strong alkaline inhibitor and cleanser in the first place, I certainly wouldnt be adding Brick acid to any kind of system water

 

[Nozzle]

The OP isn't musing over whether an alkaline inhibitor should be added. It's already been done.

Nozzle

 

[ianmcd]

The OP isn't musing over whether an alkaline inhibitor should be added. It's already been done.

Nozzle

Exactly my point, I never said anything about adding it now, the problem started when he did it initially