De ionised water in cooling circuit

[fontmell]

Hi

I was watching someone service a Volvo 20 HP engine in a sail boat with closed circuit heat exchanger, he was mixing Volvo anti freeze with De ionised water . Does anyone know the merits of doing this as I have never seen it before and recall de ionised water should not be used in car radiators but don't know why.

Thanks

 

[coopec]

Of course De-ionised water is distilled water. You do know that don't you?
(I only found that out minutes ago)

Here are a few links along the same lines as your comment

https://www.pistonheads.com/gassing/topic.asp?t=1270208

Can I use deionised water in coolant?
Deionized water is water that is acidic from the H+ ions. Yes, this is an old myth. Both types of pure water are deionized. Years ago many mechanics always said NEVER to use distilled water as it "was hungry" for metal and that you should use only tap water or else you would eat right through your radiator.Nov 12, 2009
https://www.bobistheoilguy.com › forums › ubbthreads

Do I need to mix coolant with distilled water?
By itself, distilled water, is much better at heat transfer compared to antifreeze/coolants. However, water, by itself, causes the metal parts in the cooling system to corrode. ... Thus, the best mix for a climate like ours is a 10-90 or 20-80 mix of antifreeze/coolant and distilled water.May 15, 2018

 

[TSB240]

Hi

I was watching someone service a Volvo 20 HP engine in a sail boat with closed circuit heat exchanger, he was mixing Volvo anti freeze with De ionised water . Does anyone know the merits of doing this as I have never seen it before and recall de ionised water should not be used in car radiators but don't know why.

Thanks

In theory De-Ionized water will seek out any hard scale left in the system that has not been flushed out .
I am not sure about the merits of doing this when combining it with antifreeze. I would have thought it would work better on its own initially. Antifreeze in a closed boat cooling system is designed to prevent scale and this is why it is recommended to change at a minimum of every two years.

Removing hard scale in a car radiator can sometimes be bad as it can be the only thing left sealing it!

 

[TSB240]

Of course De-ionised water is distilled water. You do know that don't you?

You are mistaken....
"to say that the distilled water is the same as deionized water is a mistake. The terms “distilled water” and “deionized water” are often misunderstood."
http://www.waterandmorehub.com/deionized-water-vs-distilled-water/

 

[Malish]

Of course De-ionised water is distilled water. You do know that don't you?
(I only found that out minutes ago)

I suspect Vic will be along in a minute but no deionised water is not the same as distilled:
Distilled water is produced by distillation (boiling water and condensing the purer steam to make distilled water)
Deionised water is produced by removing the anions and cations from water via a variety of processes such as reverse osmosis and ion exchage.

That said, cheaply deionised water has many similarities with distilled but properly deionised water will be much purer and will be acidic, with a pH of around 4-5, this will dissolve metal (and carbonates) from a cooling system until it gains a pH close to neutral (pH7).

Would I bother with either deionised or distilled in a closed system - nope, tap water is perfectly good enough. Even if you are worried about a buildup of carbonates/limestone in the cooling water circuit, the amount present in tap water is small and you would need to have a mighty big leak (and hence regular top-ups over a long period) before it would become an issue.

 

[VicS]

Hi

I was watching someone service a Volvo 20 HP engine in a sail boat with closed circuit heat exchanger, he was mixing Volvo anti freeze with De ionised water . Does anyone know the merits of doing this as I have never seen it before and recall de ionised water should not be used in car radiators but don't know why.

Thanks

If you consult some of the the VP manuals, you will find recommended maximum concentrations for dissolved substances etc in the water used for the coolant:

If it copies :

Water quality To avoid obstruction of the cooling system, resulting in lower cooling capacity, always use clean water which complies with the requirements in ASTM D4985. If the water can not be purified to comply with this demand, distilled water or pre-mixed coolant must be used.
ASTM D4985:
Total solid particles < 340 ppm,
Total hardness: < 9.5° dH,
Chloride < 40 ppm,
Sulfate < 100 ppm,
pH value 5.5–9, Silica < 20 mg SiO2/l,
Iron < 0.10 ppm,
Manganese < 0.05 ppm,
Conductivity < 500 µS/cm,
Organic content, CODMn < 15mg kMnO4/l​

Most tap water except in areas with high hardness will probably fall within these limits. If in doubt use distilled, deionised or demineralised for diluting the antifreeze ......... OR simply buy it ready diluted as suggested above ( 9.5 DH is moderately hard. In areas of high hardness it can be considerably higher, double even)

VP are the only ones where I have seen this mentioned but it applies equally to all engines

"Thinwater" if he is around is the forum expert on this.

 

[RichardS]

I suspect Vic will be along in a minute but no deionised water is not the same as distilled:
Distilled water is produced by distillation (boiling water and condensing the purer steam to make distilled water)
Deionised water is produced by removing the anions and cations from water via a variety of processes such as reverse osmosis and ion exchage.

That said, cheaply deionised water has many similarities with distilled but properly deionised water will be much purer and will be acidic, with a pH of around 4-5, this will dissolve metal (and carbonates) from a cooling system until it gains a pH close to neutral (pH7).

Would I bother with either deionised or distilled in a closed system - nope, tap water is perfectly good enough. Even if you are worried about a buildup of carbonates/limestone in the cooling water circuit, the amount present in tap water is small and you would need to have a mighty big leak (and hence regular top-ups over a long period) before it would become an issue.

We've been through this many times before. Although the two processes of distillation and de-ionisation are different, the final product is virtually identical such that for use in any domestic or industrial processes the two are interchangeable. It is only for use in analytical laboratories when levels at ppm are being measured for scientific purposes that there is any distinction to be drawn.

I use ion-exchanged softened water for coolant systems and tumble dryer (aka distilled) water for batteries, although all applications could use distilled or de-ionised if it was cheaply available in sufficient quantities.

Richard

 

[Malish]

my paragraph #2

 

[RichardS]

my paragraph #2

All water absorbs CO2 from the atmosphere and de-ionised water is no different. There is absolutely no difference in domestic applications between distilled and any de-ionised water.

Richard

 

[lw395]

We've been through this many times before. Although the two processes of distillation and de-ionisation are different, the final product is virtually identical such that for use in any domestic or industrial processes the two are interchangeable. It is only for use in analytical laboratories when levels at ppm are being measured for scientific purposes that there is any distinction to be drawn.

I use ion-exchanged softened water for coolant systems and tumble dryer (aka distilled) water for batteries, although all applications could use distilled or de-ionised if it was cheaply available in sufficient quantities.

Richard

Ion exchange softened water isn't the same thing at all!

 

[Momac]

The following antifreeze supplier suggests using deionised water but may also use tap water
https://www.smithandallan.com/produ...mith-and-allan-antifreeze-concentrate-bs6580/

For a small engine the use of a ready mixed product is no great expense.

 

[RichardS]

Ion exchange softened water isn't the same thing at all!

Good grief LW .... after all our years on this forum and all the posts where I have explained to forumites exactly how water softeners work, I would have thought that you would have remembered that I used to be a professional research chemist and would know the difference at a molecular level between de-ionised water and ion-exchanged softened water.

Richard

 

[Malish]

Good grief LW .... after all our years on this forum and all the posts where I have explained to forumites exactly how water softeners work, I would have thought that you would have remembered that I used to be a professional research chemist and would know the difference at a molecular level between de-ionised water and ion-exchanged softened water.

Richard

I would be careful mixing molecules and ions in the same sentence ;-)

 

[RichardS]

I would be careful mixing molecules and ions in the same sentence ;-)

In most cases, they co-exist quite happily.

Richard

 

[VicS]

In most cases, they co-exist quite happily.

Richard

Better explain dissociation constants and all that guff.

 

[thinwater]

Hi

I was watching someone service a Volvo 20 HP engine in a sail boat with closed circuit heat exchanger, he was mixing Volvo anti freeze with De ionised water . Does anyone know the merits of doing this as I have never seen it before and recall de ionised water should not be used in car radiators but don't know why.

Thanks

By ASTM specification, ONLY deionized water can be mixed with engine coolant during manufacture. The rules for DIYs are slightly relaxed, but still have limits on hardness. And NEVER softened water.

(Not guessing. 25 years in the coolant manufacturing industry and many years on standards development committees. Look up the ASTM standard D3306. Yes, this is also the UK standard, since the UK organization merged with ASTM ~ 15 years ago.)

 

[Lon nan Gruagach]

By ASTM specification, ONLY deionized water can be mixed with engine coolant during manufacture. The rules for DIYs are slightly relaxed, but still have limits on hardness. And NEVER softened water.

(Not guessing. 25 years in the coolant manufacturing industry and many years on standards development committees. Look up the ASTM standard D3306. Yes, this is also the UK standard, since the UK organization merged with ASTM ~ 15 years ago.)

He say anti-freeze, you (as I would expect) say coolant.
Am I right in thinking that it does more than stop the water freezing?

 

[tross]

From VicS

"VP are the only ones where I have seen this mentioned but it applies equally to all engines"

Yanmar recommend exactly the same.

 

[thinwater]

He say anti-freeze, you (as I would expect) say coolant.
Am I right in thinking that it does more than stop the water freezing?

In a closed circuit system you use engine coolant, just as for an automobile.
* Freeze protection.
* Boil protection (the boiling point is higher than water--most cars will overheat with water, or at least boil in hot spots).
* Corrosion protection. This is vital in radiators, sleeved engines, thermostats, and many small places. Also scale reduction.

Antifreeze is just for freeze protection, such as water pipes and fire mains. Even commercial AC units that run glycol don't call it antifreeze; it is gylcol heat transfer fluid.

 

[VicS]

He say anti-freeze, you (as I would expect) say coolant.
Am I right in thinking that it does more than stop the water freezing?

Yes the mixture we use, typically 50% ethane diol, lowers the freezing point considerably and also raises the boiling point a little. It also contains additives which minimise corrosion of the cooling system.

it should perhaps be called "antifreeze and summer coolant"

There are some downsides. Notably an increase in viscosity requires more pumping power and a reduction in specific heat capacity requires a greater flow rate ( a double whammy there)