We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)



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Brian Reay wrote:

How often do you need to re-pressurise a system?

Depends how much it's leaking :-P

Andy Burns wrote in news:g3rpruFfaqvU1
@mid.individual.net:

Brian Reay wrote:

How often do you need to re-pressurise a system?

Depends how much it's leaking :-P


Or how much gas is liberated from the water.

"DerbyBorn" wrote in message
2.236...
Andy Burns wrote in news:g3rpruFfaqvU1
@mid.individual.net:

Brian Reay wrote:

How often do you need to re-pressurise a system?

Depends how much it's leaking :-P


Or how much gas is liberated from the water.

very true.... I have no leaks on my house system but have to bleed one or
two of the radiators and re-pressurise quite often ......the one at my
static caravan however never needs re-pressurising for some reason .....

On 30/10/2018 19:51, DerbyBorn wrote:
Andy Burns wrote in news:g3rpruFfaqvU1
@mid.individual.net:

Brian Reay wrote:

How often do you need to re-pressurise a system?

Depends how much it's leaking :-P


Or how much gas is liberated from the water.


I'm assuming it has inhibitor which tends to reduce the 'release' of gas.

I was hoping for a typical answer in a system with no real leaks-
although even a sealed system will leak a bit.

For example, with a conventional system (ie unpressurised), I'd say,
even with no leaks, inhibitor, etc, bleeding once a year would be
normal. Probably not air in all rads, but a bit in a few.

Would that be typical for a pressurised system, or would more often be
required?

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On 30/10/18 20:18, Brian Reay wrote:
On 30/10/2018 19:51, DerbyBorn wrote:
Andy Burns wrote in news:g3rpruFfaqvU1
@mid.individual.net:

Brian Reay wrote:

How often do you need to re-pressurise a system?

Depends how much it's leaking :-P


Or how much gas is liberated from the water.


I'm assuming it has inhibitor which tends to reduce the 'release' of gas.

I was hoping for a typical answer in a system with no real leaks-
although even a sealed system will leak a bit.

For example, with a conventional system (ie unpressurised), I'd say,
even with no leaks, inhibitor, etc,Â* bleeding once a year would be
normal. Probably not air in all rads, but a bit in a few.

Would that be typical for a pressurised system, or would more often be
required?


Mine took a hell of a lot of bleeding - lasted about a month. That's
partly because I have a tortuous pipe route upstairs with 3 full
up/downs to get to some rads. It's unavoidable.

Most of that was trapped bubbles of air arriving at the bathroom towel
rail which seemed to be the place where it all gathered.

Some must have been dissolved air coming out too.

I would not expect much of any hydrogen due to the inhibitor. It should
settle down in a week or 3 and not produce any gas really.


--
Email does not work

On 30/10/2018 22:05, Tim Watts wrote:

Mine took a hell of a lot of bleeding - lasted about a month. That's
partly because I have a tortuous pipe route upstairs with 3 full
up/downs to get to some rads. It's unavoidable.

Most of that was trapped bubbles of air arriving at the bathroom towel
rail which seemed to be the place where it all gathered.

It seems to be quite often the case that there are one or two rads in
particular that cop most of the air in many system. (you can usually
predict which it will be - its the most awkward to get at and bleed!)

In my case its a small rad at the back of the upstairs airing cupboard
that I can only reach by laying on the floor and trying to slide under
and past lots of slatted shelving and piles of laundry etc.


--
Cheers,

John.

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On 30/10/2018 20:18, Brian Reay wrote:
On 30/10/2018 19:51, DerbyBorn wrote:
Andy Burns wrote in news:g3rpruFfaqvU1
@mid.individual.net:

Brian Reay wrote:

How often do you need to re-pressurise a system?

Depends how much it's leaking :-P


Or how much gas is liberated from the water.


I'm assuming it has inhibitor which tends to reduce the 'release' of gas.

I was hoping for a typical answer in a system with no real leaks-
although even a sealed system will leak a bit.

For example, with a conventional system (ie unpressurised), I'd say,
even with no leaks, inhibitor, etc,Â* bleeding once a year would be
normal. Probably not air in all rads, but a bit in a few.

In a vented system the primary water is constantly exposed to air in the
header tank, so it can absorb more air. The is also the danger than it
can pump over or draw air in directly via the F & E pipes. Lastly you
can get gas produced as a result of corrosion - again more likely on a
vented system because of the constant availability of fresh O2

Would that be typical for a pressurised system, or would more often be
required?

If filled from scratch, you will probably have to bleed and top up
several times in the first few weeks - it takes a while for all the
entrained air to come out of suspension. Once its working normally, I
would not expect to touch it more than once or twice a year - perhaps a
bit more at the start of a season if the rad circuit has been off for a
while.

Note that leaks can be too small to see - a weep that leaks water so
slowly it evaporates before you get a chance to see it "wet".

I had one recently at the base of a push fit fitting. The clue was
slight hint of verdigris staining on the paint on the pipe of a rad
tail[1]. Resting a bit of bog paper against it for a few days showed a
green patch forming on the paper. Not enough leak to see, but enough to
require a top up of about a litre every couple of weeks.

[1] In fact it was this one:

http://wiki.diyfaq.org.uk/index.php/...tOnRadTail.jpg

When doing bathrooms earlier in the year, I also took the chance to swap
a rad in the downstairs loo. However since I was only partly drained
down (i.e. just the upstairs pipework) I used a pushfit for the final
connection so I could work "live". Alas that cuprofit must have been
knocking about in my plumbing bag for too many years, and did not make a
perfect seal it transpired (although it did take a few months before it
started to leak)


--
Cheers,

John.

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Andy Burns formulated the question :
Depends how much it's leaking :-P

...and they all do leak to some extent..

"Brian Reay" wrote in message
news

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally something
the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will need
to repressurise it.)


yes bleed the radiators..then re-pressurise ....you will find at each end of
the flexible loop under the boiler either one tap to turn on at the rising
main mains water pressure supply to the combi to pressurise the boiler CH
radiator system loop and one at the other end of the hose to then to
"skoosh" as they say to bring up to 1 bar or so... OR only one to skooshing
tap at the rising main boiler supply with a non return valve at the other
end of the short hose pressurising loop...you will find ONLY one or two
radiators will need done now and again.....if you have a leak you will be
doing this more often.....hope that helps.....

On 30/10/2018 19:57, Jim GM4DHJ ... wrote:
"Brian Reay" wrote in message
news

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally something
the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will need
to repressurise it.)


yes bleed the radiators..then re-pressurise ....you will find at each end of
the flexible loop under the boiler either one tap to turn on at the rising
main mains water pressure supply to the combi to pressurise the boiler CH
radiator system loop and one at the other end of the hose to then to
"skoosh" as they say to bring up to 1 bar or so... OR only one to skooshing
tap at the rising main boiler supply with a non return valve at the other
end of the short hose pressurising loop...you will find ONLY one or two
radiators will need done now and again.....if you have a leak you will be
doing this more often.....hope that helps.....



Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.



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"Brian Reay" wrote in message
news
On 30/10/2018 19:57, Jim GM4DHJ ... wrote:
"Brian Reay" wrote in message
news

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something
the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need
to repressurise it.)


yes bleed the radiators..then re-pressurise ....you will find at each end
of
the flexible loop under the boiler either one tap to turn on at the
rising
main mains water pressure supply to the combi to pressurise the boiler CH
radiator system loop and one at the other end of the hose to then to
"skoosh" as they say to bring up to 1 bar or so... OR only one to
skooshing
tap at the rising main boiler supply with a non return valve at the other
end of the short hose pressurising loop...you will find ONLY one or two
radiators will need done now and again.....if you have a leak you will be
doing this more often.....hope that helps.....



Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.



cool seen those....

"Jim GM4DHJ ..." wrote in message
...

"Brian Reay" wrote in message
news
On 30/10/2018 19:57, Jim GM4DHJ ... wrote:
"Brian Reay" wrote in message
news
We've never had a pressurised CH system but eldest has recently bought
a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something
the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need
to repressurise it.)


yes bleed the radiators..then re-pressurise ....you will find at each
end of
the flexible loop under the boiler either one tap to turn on at the
rising
main mains water pressure supply to the combi to pressurise the boiler
CH
radiator system loop and one at the other end of the hose to then to
"skoosh" as they say to bring up to 1 bar or so... OR only one to
skooshing
tap at the rising main boiler supply with a non return valve at the
other
end of the short hose pressurising loop...you will find ONLY one or two
radiators will need done now and again.....if you have a leak you will
be
doing this more often.....hope that helps.....



Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.



cool seen those....

sorry as you asked was it something the home owner could do himself? I
rabbled on...sorry

On 30/10/2018 20:19, Jim GM4DHJ ... wrote:
"Jim GM4DHJ ..." wrote in message
...

"Brian Reay" wrote in message
news
On 30/10/2018 19:57, Jim GM4DHJ ... wrote:
"Brian Reay" wrote in message
news
We've never had a pressurised CH system but eldest has recently bought
a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something
the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need
to repressurise it.)


yes bleed the radiators..then re-pressurise ....you will find at each
end of
the flexible loop under the boiler either one tap to turn on at the
rising
main mains water pressure supply to the combi to pressurise the boiler
CH
radiator system loop and one at the other end of the hose to then to
"skoosh" as they say to bring up to 1 bar or so... OR only one to
skooshing
tap at the rising main boiler supply with a non return valve at the
other
end of the short hose pressurising loop...you will find ONLY one or two
radiators will need done now and again.....if you have a leak you will
be
doing this more often.....hope that helps.....



Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.



cool seen those....

sorry as you asked was it something the home owner could do himself? I
rabbled on...sorry



Both types can be done by the homeowner. The 'key type' are probably the
easier of the two, daughter/son-in-law learned to do it first time
through demo.

The loop method is on YouTube, again easy enough but a bit more fiddly.

The question was about how often it needed to be done.

As the gubbins is built into the boiler, it seems logical it is
something that may be required quite frequently. May be not.



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On 30/10/18 20:08, Brian Reay wrote:

Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.

I've got that, except it's keyless (just a fixed lever) - I like the
arrangement. Never saw the point of a loop when the boiler has
everything it needs right inside, so I made sure to specify that
particular model of WB.



--
Email does not work

On 30/10/2018 22:06, Tim Watts wrote:
On 30/10/18 20:08, Brian Reay wrote:

Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.

I've got that, except it's keyless (just a fixed lever) - I like the
arrangement. Never saw the point of a loop when the boiler has
everything it needs right inside, so I made sure to specify that
particular model of WB.




I assume the ones that need a loop are older but may be not.

The key in this on is supplied, stored in the boiler, which was fitted
when they bought the house. I assume its been there awhile, its seems in
good order etc but doesn't look brand new.

It all seems to work etc. They were given details of the people who do
the annual checks etc. I'm just curious never having owned one before.
They took a rad off to while working on a room, have repressurised the
system, etc. Seem to have the basics.

I just wasn't sure how often they'd need to repeat the repressuring
business. Once or twice a year seems to be a rule of thumb, unless there
is a leak.




--
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Remarkable Coincidences:
The Stock Market Crashes of 1929 and 2008 happened on the same
date in October. In Oct 1907, a run on the Knickerbocker Trust
Company led to the Great Depression.

On 30/10/2018 22:21, Brian Reay wrote:
On 30/10/2018 22:06, Tim Watts wrote:
On 30/10/18 20:08, Brian Reay wrote:

Its is a 'loopless' system. The gubbins to repressurise is part of
the boiler. You just pop a special 'key' in and off you go. No hose etc.

I've got that, except it's keyless (just a fixed lever) - I like the
arrangement. Never saw the point of a loop when the boiler has
everything it needs right inside, so I made sure to specify that
particular model of WB.




I assume the ones that need a loop are older but may be not.

Mine (6 years old) has a separate loop - but its a system boiler, so it
has no cold main connection.


--
Cheers,

John.

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\================================================= ================/

On 30/10/2018 22:06, Tim Watts wrote:
On 30/10/18 20:08, Brian Reay wrote:

Its is a 'loopless' system. The gubbins to repressurise is part of the
boiler. You just pop a special 'key' in and off you go. No hose etc.

I've got that, except it's keyless (just a fixed lever) - I like the
arrangement. Never saw the point of a loop when the boiler has
everything it needs right inside, so I made sure to specify that
particular model of WB.

I think the point of the loop is that if you forget to close the valves
after pressurising there is a possibility that the dirty water from the
radiators will feed back into the mains and therefore drinking water.

Aren't all CH systems pressurised other that the ones with a header
tank, i.e. "conventional" boilers?

--
Max Demian

On 30/10/18 22:45, Max Demian wrote:
On 30/10/2018 22:06, Tim Watts wrote:
On 30/10/18 20:08, Brian Reay wrote:

Its is a 'loopless' system. The gubbins to repressurise is part of
the boiler. You just pop a special 'key' in and off you go. No hose etc.

I've got that, except it's keyless (just a fixed lever) - I like the
arrangement. Never saw the point of a loop when the boiler has
everything it needs right inside, so I made sure to specify that
particular model of WB.

I think the point of the loop is that if you forget to close the valves
after pressurising there is a possibility that the dirty water from the
radiators will feed back into the mains and therefore drinking water.

No - because all loops need double check valves fitted.

Integral boiler fill valves will be designed to meet the requirements,

Aren't all CH systems pressurised other that the ones with a header
tank, i.e. "conventional" boilers?


Essentially, yes.

--
Email does not work

Brian Reay Wrote in message:

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)


We had a pressurised system in the old house, it's a while ago now
but it's not something I remember doing that often. Once or twice
a year maybe?

It's not something you need to think about much. If you notice the
pressure guage is a bit low, then just let in a bit more water to
repress irises.

It's an easy task. Easier than bleeding rads really
--
Chris French

On 30/10/2018 20:35, Chris French wrote:
Brian Reay Wrote in message:

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)


We had a pressurised system in the old house, it's a while ago now
but it's not something I remember doing that often. Once or twice
a year maybe?

It's not something you need to think about much. If you notice the
pressure guage is a bit low, then just let in a bit more water to
repress irises.

It's an easy task. Easier than bleeding rads really


Thank you. That was the kind of guide number I was looking for. It also
ties up with the 9 mths someone else posted- at least right ball park.

I agree, it doesn't seem a big job and less faffing that bleeding rads-
no mess, all in one place etc and, with the 'key' type system, not even
a 'loop' to hook up.

Part of today was spent re-routing an alarm wire for them. No big deal,
it took longer to drive there than do the job.

--

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"Brian Reay" wrote in message
news
I agree, it doesn't seem a big job and less faffing that bleeding rads- no
mess, all in one place etc and, with the 'key' type system, not even a
'loop' to hook up.

Hook up? My loop was permanently connected by "wingnut" connectors - at one
end to a tap that was connected to the rising main and at the other end to a
tap on the input to the CH system. To top up the pressure, all you had to do
was open both taps and then close them once the correct pressure had been
reached a few seconds later. I tended to open one half way and then use the
other one to control the flow rate, because this gave me finer control than
if one tap was fully open when I opened the other.

Are there some systems where the loop is *not* permanently connected and
normally isolated by taps?

"NY" wrote in message
o.uk...
"Brian Reay" wrote in message
news
I agree, it doesn't seem a big job and less faffing that bleeding rads-
no mess, all in one place etc and, with the 'key' type system, not even a
'loop' to hook up.

Hook up? My loop was permanently connected by "wingnut" connectors - at
one end to a tap that was connected to the rising main and at the other
end to a tap on the input to the CH system. To top up the pressure, all
you had to do was open both taps and then close them once the correct
pressure had been reached a few seconds later. I tended to open one half
way and then use the other one to control the flow rate, because this gave
me finer control than if one tap was fully open when I opened the other.

Are there some systems where the loop is *not* permanently connected and
normally isolated by taps?

yes and that saves contaminated CH water getting into the drinking water
system .......

"NY" Wrote in message:
"Brian Reay" wrote in message
news
I agree, it doesn't seem a big job and less faffing that bleeding rads- no
mess, all in one place etc and, with the 'key' type system, not even a
'loop' to hook up.

Hook up? My loop was permanently connected by "wingnut" connectors - at one
end to a tap that was connected to the rising main and at the other end to a
tap on the input to the CH system. To top up the pressure, all you had to do
was open both taps and then close them once the correct pressure had been
reached a few seconds later. I tended to open one half way and then use the
other one to control the flow rate, because this gave me finer control than
if one tap was fully open when I opened the other.

Are there some systems where the loop is *not* permanently connected and
normally isolated by taps?




The loop is supposed to have been disconnected when no being used
for filling the system , to stop the risk of water from the
heating circuit going back into the mains. Hence the wing nut
type things rather than nuts.

Of course in reality, everyone leaves them attached.
--
Chris French

On 30/10/18 22:28, Chris French wrote:


The loop is supposed to have been disconnected when no being used
for filling the system , to stop the risk of water from the
heating circuit going back into the mains. Hence the wing nut
type things rather than nuts.

Of course in reality, everyone leaves them attached.


In theory they should have double check valves too - so the connected is
a bit moot

--
Email does not work

On 30/10/2018 21:18, NY wrote:
"Brian Reay" wrote in message
news
I agree, it doesn't seem a big job and less faffing that bleeding
rads- no mess, all in one place etc and, with the 'key' type system,
not even a 'loop' to hook up.

Hook up? My loop was permanently connected by "wingnut" connectors

Ideally that hose should be disconnected when not actually being used to
fill the system. Hence the wing nuts to make it easy without a tool.

one end to a tap that was connected to the rising main and at the other
end to a tap on the input to the CH system. To top up the pressure, all
you had to do was open both taps and then close them once the correct
pressure had been reached a few seconds later. I tended to open one half
way and then use the other one to control the flow rate, because this
gave me finer control than if one tap was fully open when I opened the
other.

Not all systems have two taps anyway. All you really need is one tap at
the mains end, and a double check valve at the connection to the the
heating circuit.

Are there some systems where the loop is *not* permanently connected and
normally isolated by taps?

That's generally how they are supposed to work. You take the braided
hose off when done with it. ISTR there were/are water bylaws that
prohibit any closed circuit from being permanently connected to a rising
main.

--
Cheers,

John.

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On 30/10/2018 19:28, Brian Reay wrote:

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)




In the case of our system I would say after more than 6 months. If the
pressure drops our boiler won't run, so one thing to check is the system
pressure. There is a gauge and the needle would be in the red. On our
boiler I just have to turn one valve and watch the pressure rise to the
point where the needle is well in the green, but not at the top.

I would suggest that you make sure that your eldest can deal with the
problem. :-)

--
Michael Chare

On 30/10/2018 21:27, Michael Chare wrote:
On 30/10/2018 19:28, Brian Reay wrote:

We've never had a pressurised CH system but eldest has recently bought
a house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)




In the case of our system I would say after more than 6 months.Â* If the
pressure drops our boiler won't run, so one thing to check is the system
pressure. There is a gauge and the needle would be in the red. On our
boiler I just have to turn one valve and watch the pressure rise to the
point where the needle is well in the green, but not at the top.

I would suggest that you make sure that your eldest can deal with the
problem. :-)


They can do the repressuring etc, the boiler they have has gubbins that
make it easy, that isn't the question.

What I wanted to advise then was typically how often it may be required.
Partly so the do it and partly so they know if there is an issue.

Your 6 mths is in the same ball park as others. So I think twice a year
is a good guide. More often, suspect a leak. Less, don't worry ;-)





--
Always smile when walking, you never know where there is a camera ;-)

Remarkable Coincidences:
The Stock Market Crashes of 1929 and 2008 happened on the same
date in October. In Oct 1907, a run on the Knickerbocker Trust
Company led to the Great Depression.

On 30/10/2018 19:28, Brian Reay wrote:

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)



If the system has recently been drained and re-filled then it takes a
while for the air to come out so topping-up every few days might be
prudent, but thereafter it's once in a blue moon unless there's a leak.
If the pressure gets too low (0.5 Bar IME) the boiler locks-out until
the pressure is re-established.

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

One thing that you may not be aware of: there will be a pressure
(expansion) vessel to allow the water volume to increase/decrease with
temperature. The expansion vessel contains a rubber diaphragm, the dry
side of which is pressurised with air - there's a valve like those on a
car tyre. If the diaphragm fails (as happened to me) you can keep the
system going temporarily by letting air into a radiator.

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

have you ever tried getting anti freeze into a sealed system ?.....you have
to drain and then pump the stuff in.....not as easy as just tipping it into
the expension tank and draining some off as with a conventional CH system
.....

"Jim GM4DHJ ..." wrote in message
...

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

have you ever tried getting anti freeze into a sealed system ?.....you
have to drain and then pump the stuff in.....not as easy as just tipping
it into the expension tank and draining some off as with a conventional CH
system ....


I hated combi boilers and would never have one for years and was a staunch
50g cold and 25g hot conventional system man .... but combi's have improved
over the years......and condensing ones are comparatively cheap to run
.......

On 30/10/2018 21:42, Jim GM4DHJ ... wrote:
"Jim GM4DHJ ..." wrote in message
...

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

have you ever tried getting anti freeze into a sealed system ?.....you
have to drain and then pump the stuff in.....not as easy as just tipping
it into the expension tank and draining some off as with a conventional CH
system ....


I hated combi boilers and would never have one for years and was a staunch
50g cold and 25g hot conventional system man .... but combi's have improved
over the years......and condensing ones are comparatively cheap to run

Note that a combi and sealed system are not the same thing. You can have
any boiler type with a sealed system, and there are a few (although not
common) combi boilers that work with a vented system.


--
Cheers,

John.

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"Jim GM4DHJ ..." Wrote in message:

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

have you ever tried getting anti freeze into a sealed system ?.....you have
to drain and then pump the stuff in.....not as easy as just tipping it into
the expension tank and draining some off as with a conventional CH system

But you don't need to go up into the loft :-)

It's not that bad really, drain down a bit (if you have a tall
towel radiator all the better, as you only need to drain down
enough to empty that a bit


Remove the vent plug, use a funnel to pour the inhibitor in. Rressurise
--
Chris French

On 30/10/2018 21:38, Jim GM4DHJ ... wrote:
Sealed systems have a number of advantages and, AFAIK, no disadvantages.

have you ever tried getting anti freeze into a sealed system ?.....you have
to drain and then pump the stuff in.....not as easy as just tipping it into
the expension tank and draining some off as with a conventional CH system

The easy way is to get a aerosol can of inhibitor, that can be screwed
onto the filling loop point. It then forces it into the system via the
pressure in the can.

Personally I always fit a magnetic/cyclonic filter to the system just
before the main return connection into the boiler. That also makes for a
easy place to add inhibitor. Just turn the system off, close the taps
either side of the filter and drain it. Then refill it with inhibitor.

--
Cheers,

John.

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Wrote in message:

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

Don't they stop working if the pressure drops, either from leaks
or failure of the pressure vessel?
--
Biggles


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 30/10/2018 23:57, Biggles wrote:

Wrote in message:

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

Don't they stop working if the pressure drops, either from leaks
or failure of the pressure vessel?

Probably preferable to a vented system leaking indefinitely into the
fabric of the house. At least with a sealed system you are alerted to
the fact that there is a fault, and the maximum amount of water that can
leak is limited.


--
Cheers,

John.

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On 30/10/2018 23:57, Biggles wrote:

Wrote in message:

Sealed systems have a number of advantages and, AFAIK, no disadvantages.

Don't they stop working if the pressure drops, either from leaks
or failure of the pressure vessel?
--
Biggles

yes, that's what I said in the text you deleted .... but it's an
advantage because it alerts you to a problem and prevents the heat
exchanger from being fried

On 30/10/18 19:28, Brian Reay wrote:

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system? Is it normally
something the home owner would do, a bit like bleeding the rads?


If no obvious leaks, perhaps once a year to never.

I have a tiny drip on the hall rad (that gets fixed next week as we're
draining down to fit the UFH). I have given it about small 3 recharges
in the year because of that.


--
Email does not work

On 30/10/2018 19:28, Brian Reay wrote:

We've never had a pressurised CH system but eldest has recently bought a
house with one and I'm 'learning' about them ;-)

How often do you need to re-pressurise a system?

In an ideal world, never. However if you bleed rads, or have any tiny
leaks then you may need to from time to time. It should not be mor than
a couple of times a year though.

Is it normally
something the home owner would do

Yup, there is normally a "filling loop" (i.e. a connection between cold
main and heating circuit - made via a couple of taps and a non return
valve). You just open the taps and top up until you see adequate
pressure on the gauge. Note some combi boilers have the filling loop
built in, then there is usually a key of some kind to turn to add water.

a bit like bleeding the rads?

Kind of...

(I appreciate that, if you bleed the rads on such a system, you will
need to repressurise it.)

Probably yup. The "slack" in the system is taken up by an expansion
vessel - so a bit of bleeding will not necessarily require topping up.

Chapter and verse of sealed systems he

http://wiki.diyfaq.org.uk/index.php/Sealed_system_FAQ


--
Cheers,

John.

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