How often should one drain the central heating system and refill, adding
fresh water & inhibitor?

Or is just adding more inhibitor OK or even needed?

I changed a radiator a while ago, and the water in the old one was very
clean, the system has not had anything added or removed for about 10 years.

I went round and bled the radiators a few days ago (Haven't done this in
probably 10 years, none of the radiators had gas in it.

Should I worry that it is all about to fall to bits if I don't do anything!?

Thanks :-)

On Sun, 2 Apr 2006 01:05:54 +0100, "Sparks"
wrote:

How often should one drain the central heating system and refill, adding
fresh water & inhibitor?

The manufacturer instructions normally give details.

I usually do a test of the inhibitor with a test kit once a year and
add inhibitor if necessary. I drain, flush, refill and add fresh
inhibitor every three years.

This seems to work well and I have kept systems in good and clean
condition for over 20 years this way.

I originally had an open vented system and made absolutely sure that
there was no pumping over or sucking down either. It's now sealed.



Or is just adding more inhibitor OK or even needed?

If you don't want to test, then in the absence of anything else it
would be a good idea to add inhibitor every 18 months to 2 years.
Overdosing doesn't really matter and Fernox is cheap in comparison
with replacing system components.



I changed a radiator a while ago, and the water in the old one was very
clean, the system has not had anything added or removed for about 10 years.

I went round and bled the radiators a few days ago (Haven't done this in
probably 10 years, none of the radiators had gas in it.

Should I worry that it is all about to fall to bits if I don't do anything!?


No, but why would anybody not do anything when all that is involved is
about 10 minutes and about £20 in inhibitor?


--

..andy

"Andy Hall" wrote in message
...
On Sun, 2 Apr 2006 01:05:54 +0100, "Sparks"
wrote:

How often should one drain the central heating system and refill, adding
fresh water & inhibitor?

The manufacturer instructions normally give details.

I usually do a test of the inhibitor with a test kit once a year and
add inhibitor if necessary. I drain, flush, refill and add fresh
inhibitor every three years.

This seems to work well and I have kept systems in good and clean
condition for over 20 years this way.

I originally had an open vented system and made absolutely sure that
there was no pumping over or sucking down either. It's now sealed.

Or is just adding more inhibitor OK or even needed?

If you don't want to test, then in the absence of anything else it
would be a good idea to add inhibitor every 18 months to 2 years.

Overkill. 4 years is the usual time. A drain down is not necessary if the
same type of inhibitor is use, e.g., X-100.

On Sun, 2 Apr 2006 09:27:44 +0100, "Doctor Drivel"
wrote:


"Andy Hall" wrote in message
.. .
On Sun, 2 Apr 2006 01:05:54 +0100, "Sparks"
wrote:

How often should one drain the central heating system and refill, adding
fresh water & inhibitor?

The manufacturer instructions normally give details.

I usually do a test of the inhibitor with a test kit once a year and
add inhibitor if necessary. I drain, flush, refill and add fresh
inhibitor every three years.

This seems to work well and I have kept systems in good and clean
condition for over 20 years this way.

I originally had an open vented system and made absolutely sure that
there was no pumping over or sucking down either. It's now sealed.

Or is just adding more inhibitor OK or even needed?

If you don't want to test, then in the absence of anything else it
would be a good idea to add inhibitor every 18 months to 2 years.

Overkill. 4 years is the usual time. A drain down is not necessary if the
same type of inhibitor is use, e.g., X-100.



That would assume that there has been no degradation in the inhibitor.
There will be a greater tendency for this to happen in open vented
than sealed systems. If the concentration of inhibitor becomes
inadequate, corrosion will continue.


--

..andy

The Fernox web site states it has a life of 5 years
Brian H

"brian" wrote in message
oups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On 2 Apr 2006 04:05:55 -0700, "brian"
wrote:

The Fernox web site states it has a life of 5 years
Brian H


This depends on concentration and the amount of degradation, e.g. due
to introduction of dissolved air into the system

It would be very foolish to fill the system and then leave any
checking for 5 years.


--

..andy

On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
roups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.


On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

There is no such thing as a good, safe bet and certainly not in this
case.

Of course, I suppose that letting the system deteriorate would help
your counter sales of those magnetic crud catchers and radiators.
There's much more to be made out of these than a few £ on inhibitor
after all.



--

..andy

"Andy Hall" aka Matt wrote in message
...
On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
groups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.

snip lost nonesen by Matt

On Sun, 2 Apr 2006 14:32:30 +0100, "Doctor Drivel"
wrote:


"Andy Hall" aka Matt wrote in message
.. .
On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
egroups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.


This is another of your silly put downs.

Doing a job properly is doing a job properly no matter who does it.

One can buy a Sentinel Quick Test kit for £2.50. It comes with a
small pot which is filled to a line with system water and then a
tablet is added. It gives a yes/no indication.

Now I can appreciate that you might find that procedure challenging or
beyond your means but I suspect that everybody else can manage
perfectly well.


--

..andy

In article ,
wrote:
Why would anyone want to faff on and purchase and add extra inhibitor?
Mine's been in (a sealed system) for 13 years and is as good as new. (I
tested it recently.)

Your TRVs have lasted for 13 years? What make?

--
*I have a degree in liberal arts -- do you want fries with that

Dave Plowman London SW
To e-mail, change noise into sound.

I'd go with that

In message , Steve Firth
writes
Dave Plowman (News) wrote:
In article ,
wrote:
Why would anyone want to faff on and purchase and add extra inhibitor?
Mine's been in (a sealed system) for 13 years and is as good as new. (I
tested it recently.)
Your TRVs have lasted for 13 years? What make?

In our case, Danfoss. Still work just fine, installed in 1992.

Mine are 18 years old, some of them need a bit of a tap at the beginning
of the season, but they still do the job

--
geoff

"Andy Hall" wrote in message
...
On Sun, 02 Apr 2006 09:18:42 +0100, wrote:

On 2 Apr,
Andy Hall wrote:

No, but why would anybody not do anything when all that is involved is
about 10 minutes and about £20 in inhibitor?

Why would anyone want to faff on and purchase and add extra inhibitor?

Because it degrades over time and that they are sensible, I would
imagine.

The main point is to actually test. Most people don't even bother to
do that and then wonder why their systems are full of crud and they
are having to replace radiators and other system components.

Mine's
been in (a sealed system) for 13 years and is as good as new. (I tested it
recently.)

It must have been substantially over the standard concentration
requirement to begin with.

--

.andy

I know the manufacturers of inhibitor state that overdosing is OK on the
instrustions but I have seen a letter from Honeywell to a customer who
returned a 2 port valve to them that blamed overdosing of inhibitor for the
premature failure of the ball in the valve.

Adam

"Andy Hall" aka Matt wrote in message
...
On Sun, 2 Apr 2006 14:32:30 +0100, "Doctor Drivel"
wrote:

"Andy Hall" aka Matt wrote in message
. ..
On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
legroups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.

This is another of your silly put downs.

Matt, it is 4 years.

On Sun, 2 Apr 2006 23:06:37 +0100, "Doctor Drivel"
wrote:


"Andy Hall" aka Matt wrote in message
.. .
On Sun, 2 Apr 2006 14:32:30 +0100, "Doctor Drivel"
wrote:

"Andy Hall" aka Matt wrote in message
...
On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
glegroups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.

This is another of your silly put downs.

Matt, it is 4 years.


Since when were you a doctor of chemistry rather than drivel?


--

..andy

"Andy Hall" aka Matt wrote in message
...
On Sun, 2 Apr 2006 23:06:37 +0100, "Doctor Drivel"
wrote:

"Andy Hall" aka Matt wrote in message
. ..
On Sun, 2 Apr 2006 14:32:30 +0100, "Doctor Drivel"
wrote:

"Andy Hall" aka Matt wrote in message
m...
On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
oglegroups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.

This is another of your silly put downs.

Matt, it is 4 years.

Since when were you a doctor of chemistry rather than drivel?

Matt, it is 4 years.

On Mon, 3 Apr 2006 01:15:31 +0100, "Doctor Drivel"
wrote:


"Andy Hall" aka Matt wrote in message
.. .
On Sun, 2 Apr 2006 23:06:37 +0100, "Doctor Drivel"
wrote:

"Andy Hall" aka Matt wrote in message
...
On Sun, 2 Apr 2006 14:32:30 +0100, "Doctor Drivel"
wrote:

"Andy Hall" aka Matt wrote in message
om...
On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
ooglegroups.com...
The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.

This is another of your silly put downs.

Matt, it is 4 years.

Since when were you a doctor of chemistry rather than drivel?

Matt, it is 4 years.

I spoke with the technical departments of Fernox and Sentinel
Performance Solutions and obtained similar answers from both of them.

- Longevity figures quoted are typical and not guaranteed.

- BS 7593 (Code of practice for treatment of water in domestic hot
water central heating systems) calls for testing of inhibitor levels
every year.

- If there is any tendency to water loss from the system, dissolved
chloride salts in the make up water increase the load on the
inhibitor. With an open vented system it is often not obvious that
this is happening if the leaks are small - e.g. if the water is driven
off by the heat.

- Closed systems typically have about a tenth of the concentration of
dissolved oxygen as compared with open vented systems.

- If an open vented system is subject to any sucking down or pumping
over, the load on the inhibitor is increased, apart from it being a
serious problem anyway.


Given all of the above, the correct procedure is to test the inhibitor
concentration annually. Taking bets on several £k of heating system
is not prudent.





--

..andy

Andy Hall wrote:
On Sun, 2 Apr 2006 14:32:30 +0100, "Doctor Drivel"
wrote:


"Andy Hall" aka Matt wrote in message
. ..

On Sun, 2 Apr 2006 12:11:01 +0100, "Doctor Drivel"
wrote:


"brian" wrote in message
legroups.com...

The Fernox web site states it has a life of 5 years
Brian H

That's why 4 years is a good safe bet.

On something like this, where there is an expenditure of £20 if a test
indicates inadequate concentration of inhibitor vs. several £k at risk
for guessing, regular testing or refilling is the correct course of
action.

Matt, the average DIYer wouldn't know how to test the system water. He
wants ballpark, and 4 years is ballpark.



This is another of your silly put downs.

Doing a job properly is doing a job properly no matter who does it.

One can buy a Sentinel Quick Test kit for £2.50. It comes with a
small pot which is filled to a line with system water and then a
tablet is added. It gives a yes/no indication.

Now I can appreciate that you might find that procedure challenging or
beyond your means but I suspect that everybody else can manage
perfectly well.

I just drain a small amount into a jam jar and put a nail into it. I
put the same amount of fresh water into another jam jar with a nail. I
leave for a few days/weeks and then compare the two. Water from central
heating system showed no corrosion to the nail. Fresh water nail was
all brown and rusty.

D

Andy Hall wrote:
- BS 7593 (Code of practice for treatment of water in domestic hot
water central heating systems) calls for testing of inhibitor levels
every year.

Is there an easy DIY test?

On Mon, 03 Apr 2006 10:38:45 +0100, Chris Bacon
wrote:

Andy Hall wrote:
- BS 7593 (Code of practice for treatment of water in domestic hot
water central heating systems) calls for testing of inhibitor levels
every year.

Is there an easy DIY test?


Yes.


Sentinel, for example do two of them.

One is a quick test pack with all the bits (tablets and a test pot) to
do two tests. About £2.50.

http://www.sentinel-solutions.net/equipment/x100


The other is a ten test basic kit - about £9

http://www.sentinel-solutions.net/equipment/basic


Fill vessel to line, add tablet and look for colour.




--

..andy

Andrew Gabriel wrote:
Chris Bacon writes:
Is there an easy DIY test?

Run some into a large jam jar with a good sealing
lid. [ snip ]

That's similar to the "See how well it works!" tests that
were shown in pamphlets um.. some years ago!

Andy Hall wrote:
Chris Bacon wrote:
Andy Hall wrote:
- BS 7593 (Code of practice for treatment of water in domestic hot
water central heating systems) calls for testing of inhibitor levels
every year.

Is there an easy DIY test?

The [...] ten test basic kit - about £9
http://www.sentinel-solutions.net/equipment/basic

Looks good... colours are always good!