Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Comments welcome as usual.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article , John
Rumm writes
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Nice one.

Powerflushing

No. 4, should that be tapping rather then tripping :-?

Mains pressure flushing

Maybe add a warning to control mains flow such that pressure doesn't go
above 3 bar and pop the over pressure relief.
--
fred
it's a ba-na-na . . . .

On 12/12/2012 17:18, fred wrote:
In article , John
Rumm writes
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Nice one.

Powerflushing

No. 4, should that be tapping rather then tripping :-?

Yes, well spotted - difficult to trip a rad - they don't normally walk far!

Mains pressure flushing

Maybe add a warning to control mains flow such that pressure doesn't go
above 3 bar and pop the over pressure relief.

If you have isolated the boiler, then the PRV will normally be "out of
circuit" during the process - still on sealed systems that are
"assembled from bits" this might be worth keeping in mind.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article , John
Rumm writes
On 12/12/2012 17:18, fred wrote:
In article , John
Rumm writes
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Nice one.

Powerflushing

No. 4, should that be tapping rather then tripping :-?

Yes, well spotted - difficult to trip a rad - they don't normally walk far!

I thought it might be a sixties ref to Lucy and psychedelia.

Mains pressure flushing

Maybe add a warning to control mains flow such that pressure doesn't go
above 3 bar and pop the over pressure relief.

If you have isolated the boiler, then the PRV will normally be "out of
circuit" during the process - still on sealed systems that are
"assembled from bits" this might be worth keeping in mind.

Yes, my system is home grown and has the PRV just outside the box on the
flow side. I only have the boiler isolated (well, flow stopped) on the
return side as you can't really get muck in if there's no flow through.
I never bothered with full isolation as it's only a little extra water
to drain down if needs be. I think there's a requirement for an
uninterruptable path between boiler and PRV (no problem if it's
internal) and I didn't have the space on that pipework to fit PRV, fill
point and a further isolator after that.
--
fred
it's a ba-na-na . . . .

On 12/12/2012 19:02, fred wrote:
In article , John
Rumm writes
On 12/12/2012 17:18, fred wrote:
In article , John
Rumm writes
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Nice one.

Powerflushing

No. 4, should that be tapping rather then tripping :-?

Yes, well spotted - difficult to trip a rad - they don't normally walk
far!

I thought it might be a sixties ref to Lucy and psychedelia.

Na, my 60's memories are very poor ;-)

Mains pressure flushing

Maybe add a warning to control mains flow such that pressure doesn't go
above 3 bar and pop the over pressure relief.

If you have isolated the boiler, then the PRV will normally be "out of
circuit" during the process - still on sealed systems that are
"assembled from bits" this might be worth keeping in mind.

Yes, my system is home grown and has the PRV just outside the box on the
flow side. I only have the boiler isolated (well, flow stopped) on the
return side as you can't really get muck in if there's no flow through.
I never bothered with full isolation as it's only a little extra water
to drain down if needs be. I think there's a requirement for an
uninterruptable path between boiler and PRV (no problem if it's
internal) and I didn't have the space on that pipework to fit PRV, fill
point and a further isolator after that.

I added some words to accommodate such systems...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article , John
Rumm writes
On 12/12/2012 19:02, fred wrote:

Yes, my system is home grown and has the PRV just outside the box on the
flow side. I only have the boiler isolated (well, flow stopped) on the
return side as you can't really get muck in if there's no flow through.
I never bothered with full isolation as it's only a little extra water
to drain down if needs be. I think there's a requirement for an
uninterruptable path between boiler and PRV (no problem if it's
internal) and I didn't have the space on that pipework to fit PRV, fill
point and a further isolator after that.

I added some words to accommodate such systems...

Ta, looks good.
--
fred
it's a ba-na-na . . . .

On 12/12/2012 17:18, fred wrote:
In article , John
Rumm writes
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Nice one.

+1

Surely you're not going to tell us that little lot has come out of
*your* system, Mr Rumm?!:
http://wiki.diyfaq.org.uk/images/c/c...FlushWater.jpg

David

On 13/12/2012 07:54, Lobster wrote:
On 12/12/2012 17:18, fred wrote:
In article , John
Rumm writes
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Nice one.

+1

Surely you're not going to tell us that little lot has come out of
*your* system, Mr Rumm?!:
http://wiki.diyfaq.org.uk/images/c/c...FlushWater.jpg

That and a whole lot more...

And that was with regular dosing with inhibitor, and treatment with
descaler/boiler noise reducer!

Although its probably worth pointing out that was only regular for the 4
years I owned it - what happened in the previous 20 odd is anyone's
guess - although I have a suspicion it did not get much in the way of
love and attention.

Even with a bit of tweaking under my stewardship it still pumped over a
little from time to time. The system was also inappropriate for the
property, since it was vented, but really had insufficient head which
made it rather too easy for it to suck in air from time to time. So I
was not expecting it to be pretty.

So there was plenty of black water as you can see. I was directing it
into that basin tangentially - so it tended to spin the water, which was
quite handy because it dropped most of the heavy stuff in the middle of
the basin (the plughole is to the side) which made it easy to see how
much heavy stuff was coming out. As I could get plenty of flow rate
through it, most of the fine stuff lifted and flushed quiet easily.
There must have been the equivalent of a few cupfuls of heavy
particulate / magnetite observed though.

To clean it I chucked in a couple of litres of cleaner, and left that
circulating for a week or so. Then I drained down and capped off the
vent and feed pipes. Then flushed everything as described, doing one rad
at a time until each rad ran nice and clear (remembering to open the
valve on the next before closing it on the previous one - so you don't
accidentally try and take the whole system up to 5 bar!). I then
reversed the flow direction and repeated the whole process. That shifted
a surprising amount of extra stuff that I was not expecting.

Later I set about rad juggling / upgrading as required, so got a chance
to take a few rads right out of circuit and flush them individually to
see what had been missed. The answer being nothing of note, so I was
reasonably confident the rest of the system was clean.

Since the new system has been running I have checked the TF1 after a
couple of months. The water it had in it was discoloured a bit but not
too bad. It had also trapped about a teaspoon of particulates and magnetite



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 12/12/2012 15:59, John Rumm wrote:
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Comments welcome as usual.



What would be a reasonable quote/cost to flush an 8 radiator with combi
boiler system.

On 12/12/2012 19:57, Bob H wrote:
On 12/12/2012 15:59, John Rumm wrote:
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Comments welcome as usual.



What would be a reasonable quote/cost to flush an 8 radiator with combi
boiler system.

Short answer is, I don't know. I know doing my system (21 rads) via the
mains flush technique took about 3/4 of a day to do well[1]. So perhaps
half a day to do a proper job on a 8 rad system. Convert that into
typical day rates in your area, and add cost of chemicals. Seems like
£200 would be a starting point.

[1] Its also surprisingly knackering by the time you have walked back
and forth to each rad about six times, and fiddled with valves at floor
level!

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm writes:
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Comments welcome as usual.

Some guidance on frequency...

A sealed system with inhibitor which never or rarely needs
topping up or bleeding can run for many years without draining.
(I've gone for 7 years, and the inhibitor was still working
and the water clear.)

Vented systems and sealed systems which need regular topping up
will lose their inhibitor, and if it's not topped up, they will
sludge up.

Bleed a little water out, and if it's dark, that's a good indication
that the system has seen some corrosion, and should be drained and
refilled with inhibitor, or flushed if very dirty.


When draining a vented system, the header tank can have quite a
crust of floating sludge. Skim this off using a jug first, so it
doesn't get washed into the pipework.


Be prepared for drain valves that
a) won't open, and then
b) won't close. ;-)

I was lucky I had bought an Aldi plumbing washer set a few weeks
before I drained down a friend's system, as the remains of the
rubber washer in the drain cock washed out with the black water.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

My parents' system had a Primatic cylinder and the boilers were changed from
solid fuel to oil, then to gas over the course of nearly 50 years without
being flushed and probably without inhibitor. The stuff that came out of the
radiators when they were bled once or twice in the 30 years that I can
remember was certainly rather black and like a suspension of graphite.
I believe it was flushed and had inhibitor added when the Primatic and
boiler were replaced by a gas condensing combi-boiler a couple of years ago
and has worked fine since, without leaks.

In article ,
"Martin Crossley" writes:
My parents' system had a Primatic cylinder and the boilers were changed from
solid fuel to oil, then to gas over the course of nearly 50 years without
being flushed and probably without inhibitor. The stuff that came out of the
radiators when they were bled once or twice in the 30 years that I can
remember was certainly rather black and like a suspension of graphite.
I believe it was flushed and had inhibitor added when the Primatic and
boiler were replaced by a gas condensing combi-boiler a couple of years ago
and has worked fine since, without leaks.

50+ year old radiators were much thicker and designed before inhibitors
were used, and expected to last the life of the building, and for the
most part will still be fine even if no inhibitor has ever been used.

For anything newer, this becomes less and less true, and any bought in
the last 10 years will have a very short life if no inhibitor used, and
even if it is, you are most unlikely to get anything like 50 years out
of them.

I can see this in my parents system which was installed by dad in 1959.
All the original radiators are still fine. Radiators added in 1967
lasted 25-30 years. Radiators added in the mid 1970's lasted 20 years.
A radiator added in 1990 lasted 5 years.
Since 1998, the system has had inhibitor added (due to a new boiler),
and only one more failure which was a new radiator a couple of years
before the inhibitor was added.

I could probably plot a graph which would show something like any
radiator bought before 1965 would last forever, and any radiator
bought after 1965 would die by the year 2000, without inhibitor.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 13/12/2012 09:49, Andrew Gabriel wrote:
In article ,
"Martin Crossley" writes:
My parents' system had a Primatic cylinder and the boilers were changed from
solid fuel to oil, then to gas over the course of nearly 50 years without
being flushed and probably without inhibitor. The stuff that came out of the
radiators when they were bled once or twice in the 30 years that I can
remember was certainly rather black and like a suspension of graphite.
I believe it was flushed and had inhibitor added when the Primatic and
boiler were replaced by a gas condensing combi-boiler a couple of years ago
and has worked fine since, without leaks.

50+ year old radiators were much thicker and designed before inhibitors
were used, and expected to last the life of the building, and for the
most part will still be fine even if no inhibitor has ever been used.

For anything newer, this becomes less and less true, and any bought in
the last 10 years will have a very short life if no inhibitor used, and
even if it is, you are most unlikely to get anything like 50 years out
of them.

I can see this in my parents system which was installed by dad in 1959.
All the original radiators are still fine. Radiators added in 1967
lasted 25-30 years. Radiators added in the mid 1970's lasted 20 years.

My parents had CH installed in the mid-60s when I were a lad, and mum
still lives there; I'm pretty sure all the original radiators are still
present. Maybe time she moved!

David

On Thu, 13 Dec 2012 09:49:29 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
"Martin Crossley" writes:
My parents' system had a Primatic cylinder and the boilers were changed from
solid fuel to oil, then to gas over the course of nearly 50 years without
being flushed and probably without inhibitor. The stuff that came out of the
radiators when they were bled once or twice in the 30 years that I can
remember was certainly rather black and like a suspension of graphite.
I believe it was flushed and had inhibitor added when the Primatic and
boiler were replaced by a gas condensing combi-boiler a couple of years ago
and has worked fine since, without leaks.

50+ year old radiators were much thicker and designed before inhibitors
were used, and expected to last the life of the building, and for the
most part will still be fine even if no inhibitor has ever been used.

For anything newer, this becomes less and less true, and any bought in
the last 10 years will have a very short life if no inhibitor used, and
even if it is, you are most unlikely to get anything like 50 years out
of them.

I can see this in my parents system which was installed by dad in 1959.
All the original radiators are still fine. Radiators added in 1967
lasted 25-30 years. Radiators added in the mid 1970's lasted 20 years.
A radiator added in 1990 lasted 5 years.
Since 1998, the system has had inhibitor added (due to a new boiler),
and only one more failure which was a new radiator a couple of years
before the inhibitor was added.

I could probably plot a graph which would show something like any
radiator bought before 1965 would last forever, and any radiator
bought after 1965 would die by the year 2000, without inhibitor.

Including those fitted in 2001? ;-)
--
(\__/) M.
(='.'=) If a man stands in a forest and no woman is around
(")_(") is he still wrong?

In article ,
Mark writes:
On Thu, 13 Dec 2012 09:49:29 +0000 (UTC),
(Andrew Gabriel) wrote:
I could probably plot a graph which would show something like any
radiator bought before 1965 would last forever, and any radiator
bought after 1965 would die by the year 2000, without inhibitor.

Including those fitted in 2001? ;-)

Just treat them as consumables... :-(

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 13/12/2012 00:38, Andrew Gabriel wrote:


Bleed a little water out, and if it's dark, that's a good indication
that the system has seen some corrosion, and should be drained and
refilled with inhibitor, or flushed if very dirty.


Is there any significant difference of interpretation between it being
blackish or rusty brown?

--
Rod

On 13/12/2012 00:38, Andrew Gabriel wrote:
In article ,
John Rumm writes:
Since it has come up a few times recently, and I had a couple of photos
handy:

http://wiki.diyfaq.org.uk/index.php?...ating_flushing

Comments welcome as usual.

Some guidance on frequency...

A sealed system with inhibitor which never or rarely needs
topping up or bleeding can run for many years without draining.
(I've gone for 7 years, and the inhibitor was still working
and the water clear.)

Vented systems and sealed systems which need regular topping up
will lose their inhibitor, and if it's not topped up, they will
sludge up.

Bleed a little water out, and if it's dark, that's a good indication
that the system has seen some corrosion, and should be drained and
refilled with inhibitor, or flushed if very dirty.


When draining a vented system, the header tank can have quite a
crust of floating sludge. Skim this off using a jug first, so it
doesn't get washed into the pipework.

Yup good point - pinched that ;-)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/