CH inhibitor life and sealed vs. unsealed systems

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Hi,

Please can anyone tell me how often the CH should be drained down and
the inhibitor replaced? I've got two years in my head but I might be
thinking of car antifreeze (the blue rather than red version)!

I've been using fernox but their web site is a bit vague on the issue
and says to buy a tester. Inhibitor is readily available but I don't
see anyone selling tests and I wonder if I did, whether the test would
cost more than the inhibitor!

I can't remember whether I used F1 or MB1 last time, if that make a
difference, I have used both in the past; buying whichever was the
best price in the past at the time.

It is a vented system. Would the interval be longer in a sealed
system? I imagine the F&E tank constantly allows oxygen into the
system whereas a sealed system contains only a finite amount?

Is it worth me converting the system to a sealed type? What is
involved in this? I know many here like sealed systems and say that
there is only a finite volume of water so leaks are limited, but what
other advantages are there? Some would say no need for a loft tank but
to be fair, that hardly takes up any room.

Regarding the drain down, is it worth using a cleaner beforehand like
Fernox F3? I know I used one when we first moved in and didn't know
the condition of the system but since then we have changed a lot of
the radiators as we have redecorated the rooms, so I am quite
confident that the system is in good shape now. Is cleaner only needed
in bad / dirty systems? Fernox say to use it but they have an interest
in generating sales!

TIA

Re: CH inhibitor life and sealed vs. unsealed systems

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If I remember right MB1 is for use on boilers with a cast iron heat
exchanger, F1 for copper.
If you put the right ammount in should last for years with out changing.
I personally wouldn't go down the combi road unless my old baxi packed up,
fingers crossed



Re: CH inhibitor life and sealed vs. unsealed systems
On 16/04/12 17:00, Fred wrote:
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 From the Fernox site...


"What is the difference "between Fernox MB-1 and F1?
The Protector MB-1 4 litre and Protector F1 500ml are both Buildcert
approved inhibitors and are equally as effective in protecting the
system from the effects of corrosion and limescale. Both products treat
100 litre systems or 10 single radiators.

The MB-1 is a heritage product and its formulation requires a larger
unit pack size but it has a loyal customer base and as such has a place
in the market. The Protector F1 500ml is a concentrated product which is
favoured by installers and homeowners who prefer to use smaller packaged
products, which are easier to handle and transport.

The efficacy of both products is the same. Another example might be
washing powders, which are available as loose powder, gels, liquids and
tablet form in varying pack sizes.

It is a matter of personal choice which product to buy. "

Re: CH inhibitor life and sealed vs. unsealed systems
wrote:

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On the whole I prefer a sealed system but getting in inhibitor is
slightly harder since you have no header tank.  A failure in a vented
system could mean unlimited amounts of water in your house but this
should be unlikely if you look after it.

In your situation I wouldn't bother converting it but, for a
completely new system, it's definitely worth considering.  I converted
mine to sealed because I wanted to lose the header tank and the hot
water cylinder.
--
(\__/)  M.
(='.'=) If a man stands in a forest and no woman is around
We've slightly trimmed the long signature. Click to see the full one.
Re: CH inhibitor life and sealed vs. unsealed systems
On Tue, 17 Apr 2012 14:16:03 +0100, Mark

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Thanks. I was only thinking of switching to a sealed CH; I would keep
the vented HW for now.

Re: CH inhibitor life and sealed vs. unsealed systems
On Monday, April 16, 2012 5:00:15 PM UTC+1, Fred wrote:
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You don't drain it, just top it up. You need to drain car anti-freeze becau=
se the ethylene glycol degrades with age and turn into an acidic compound w=
hich starts rapid corrosion.

  Domestic CH inhibitors are usually sodium molybdate, so you can't overdos=
e it SFAIK.

  If you're considering changing to a sealed system, I'd suggest you shut o=
ff the fill valve and monior the water level. An open vented system can top=
 up a leaking systems for years without being noticed; it causes corrosion =
problems. The same leak on a sealed system will require regular topping up.

   You need to check your boiler is suitable, the manual will tell you. It =
needs a manual- reset overheat thermostat; not all have them.

Re: CH inhibitor life and sealed vs. unsealed systems
wrote:

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Thanks. I hadn't realised the difference. I had wrongly assumed you
flushed out the "spent" inhibitor; it seems I have been making extra
work for myself!

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