Any problems in mixing different brands of central heating inhibitor?

I've got to replace three radiators and, unlike previous occasions when
I've been able to save the water I've drained before putting it back
into the header tank, this time I'm likely to lose quite a lot. The
current brand is one that I don't recognise and so I'm going to have to
use another to top up with: Triple X (94504) from Toolstation?

TIA

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F

F wrote:
Any problems in mixing different brands of central heating inhibitor?

I've got to replace three radiators and, unlike previous occasions when
I've been able to save the water I've drained before putting it back
into the header tank, this time I'm likely to lose quite a lot. The
current brand is one that I don't recognise and so I'm going to have to
use another to top up with: Triple X (94504) from Toolstation?

I've asked the same question here before and been advised that it's not
a good idea, so have not mixed types myself.

Given that you have the luxury of actually knowing what's currently in
there, I'd certainly be inclined to track that down the same brand again
to top up; better than having to flush out the whole system and
replacing it (though that being said, given that the system's in bits
anyway, flushing out shouldn't be too much of a pain.

David

Lobster wrote:
F wrote:
Any problems in mixing different brands of central heating inhibitor?

I've got to replace three radiators and, unlike previous occasions
when I've been able to save the water I've drained before putting it
back into the header tank, this time I'm likely to lose quite a lot.
The current brand is one that I don't recognise and so I'm going to
have to use another to top up with: Triple X (94504) from Toolstation?

I've asked the same question here before and been advised that it's not
a good idea, so have not mixed types myself.

Given that you have the luxury of actually knowing what's currently in
there, I'd certainly be inclined to track that down the same brand again
to top up; better than having to flush out the whole system and
replacing it (though that being said, given that the system's in bits
anyway, flushing out shouldn't be too much of a pain.

David

I don't think there's much difference between any of them. Usually a
mild acid, such as boric, and a surfactant to aid dispersion. Even if
they're not all the same, I can't see them being incompatible

On 22/11/2009 13:08 Lobster wrote:

I'd certainly be inclined to track that down the same brand again
to top up; better than having to flush out the whole system and
replacing it (though that being said, given that the system's in bits
anyway, flushing out shouldn't be too much of a pain.

We've got concrete floors so all the rads are on pipes that drop down
from the ceiling which means 9 drain points (or 9 radiators to turn off
in turn and then reset) if I'm not going to be pushing an ever weakening
mixture of water and inhibitor around...

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F

On 22/11/2009 12:06 F wrote:

Triple X (94504) from Toolstation?

Anyone got any experience of this brand?

Are they all pretty much the same?

--
F

F wrote:
On 22/11/2009 12:06 F wrote:

Triple X (94504) from Toolstation?

Anyone got any experience of this brand?

Are they all pretty much the same?


They're all mildly acidic. AFAIK the rest is hype

One main active ingredient is Molybdenum. It is its concentration what is tested to assess if the system is corrected inhibited (like the Sentinel x100 Quick Test). Optimum concentration is 330ppm of molybdate

Molybdenum is expensive and I've been told by a manufacturer that its concentration varies across inhibitors.

On 24 Nov, 12:52, Stuart Noble wrote:
F wrote:
On 22/11/2009 12:06 F wrote:

Triple X (94504) from Toolstation?

Anyone got any experience of this brand?

Are they all pretty much the same?

They're all mildly acidic. AFAIK the rest is hype

Manufacturer's instructions usually recommend that you don't mix them.
This may be taken as a ploy to ensure they sell more of their own
brand, but I wouldn't mix inhibitors.

Some brands ( Sentinel, I think) contain sodium molybdate which works
by putting a coating on the steel surfaces. Other brands contain
nitrites. I've been told that mixing molybdates and nitrites will
generate ammonia and attack brass components. You may get some idea
fom the COSHH data sheets, but you don't know what's in it and
shouldn't mix them. I think the molybdate is the quality/expensive
stuff.

Come to think of it, I was involved with a commercial job where water
treatment contractors were given records of the existing inhibitors
and still put the wrong stuff in. Much system failure, embarrassment
and air locking resulted, followed by much flushing and very little
discussion of what they'd done.

On 22 Nov, 12:06, F news@nowhere wrote:
Any problems in mixing different brands of central heating inhibitor?

You've probably all lost interest in this by now, or you've mixed the
inhibitors anyway.

There's a brief description here;
http://www.infrastructure.alberta.ca...TechPres29.pdf

There are 4 types of closed-circuit inhibitors listed (sulphite,
silicate, nitrite, molybdate) up to page 5, after which it goes onto
open circuit and steam boilers.

Of these 4, silicate is the only one I haven't come across, the other
3 I know to be in use in CH inhibitor solutions.

So no, you definitely shouldn't mix them unless you happen to know
that the active ingredients are the same.