Just converted my CH system to sealed but when I fill with water
nothing is registering on the pressure gauge.

I have left the incoming mains on until the pressure relief valve goes
off (indicating 3bar) and still absolutely nothing registering on the
pressure gauge.

Water is peeing across the room when I let water out of the radiator
vents!

I removed the gauge from the expansion vessel and the back of the gauge
has a hole in. Should it have a pin sticking out of it rather than a
hole ?

I removed the front cover of the gauge and the needle pings back to 0
if I gently push it so I don't think it is stuck.

Can anyone confirm my diagnosis. The fact that the PRD goes off must
mean I have reached 3 bar ?

Do these devices usually fail or could I have damaged it when fitting
it ?

Can you buy replacements seperately ?

TIA for any help.

Also forgot to add that I checked the pressure on the air side of the
expansion vessel and it measured 22 psi which is 1.5 bar. This agrees
with the pre-charge details on the side of the vessel.

So far the system has only been run on cold as the gas has not been
connected to the boiler yet.

wrote:

Just converted my CH system to sealed but when I fill with water
nothing is registering on the pressure gauge.

I have left the incoming mains on until the pressure relief valve goes
off (indicating 3bar) and still absolutely nothing registering on the
pressure gauge.

Water is peeing across the room when I let water out of the radiator
vents!

I removed the gauge from the expansion vessel and the back of the gauge
has a hole in. Should it have a pin sticking out of it rather than a
hole ?

I removed the front cover of the gauge and the needle pings back to 0
if I gently push it so I don't think it is stuck.

Can anyone confirm my diagnosis. The fact that the PRD goes off must
mean I have reached 3 bar ?

Do these devices usually fail or could I have damaged it when fitting
it ?

Can you buy replacements seperately ?

TIA for any help.

Isn't the gauge on the expansion vessel for telling you what pressure
the gas in the expansion vessel is at, not the water in the system? If
there is no gas I would expect it to read 0 whatever pressure the water
was at.

I may well be wrong though...

On 24 Dec 2005 06:50:39 -0800, wrote:

Just converted my CH system to sealed but when I fill with water
nothing is registering on the pressure gauge.

I have left the incoming mains on until the pressure relief valve goes
off (indicating 3bar) and still absolutely nothing registering on the
pressure gauge.

Water is peeing across the room when I let water out of the radiator
vents!

So there's pressure, but that was obvious from the relief valve.


I removed the gauge from the expansion vessel and the back of the gauge
has a hole in. Should it have a pin sticking out of it rather than a
hole ?

Mine don't, but it could be a different type.


I removed the front cover of the gauge and the needle pings back to 0
if I gently push it so I don't think it is stuck.

Can anyone confirm my diagnosis. The fact that the PRD goes off must
mean I have reached 3 bar ?

Unless it was faulty as well, then yes. 3bar would be too high in
operation anyway.



Do these devices usually fail or could I have damaged it when fitting
it ?

Possible I suppose, but they are not sophisticated devices. There
isn't some kind of shut off, is there? e.g. rotating the gauge or a
little screw in the manifold or something of that nature?



Can you buy replacements seperately ?


Yes you can, but doubtful until Tuesday. Heating merchant or

Otherwise try www.bes.ltd.uk

part 12149 or 12150



--

..andy

Also forgot to add that I checked the pressure on the air side of the
expansion vessel and it measured 22 psi which is 1.5 bar. This agrees
with the pre-charge details on the side of the vessel.

So far the system has only been run on cold as the gas has not been
connected to the boiler yet.

Just had another look at the instructions. The make is Altecnic.

The only instructions referring to the pressure gauge say "Set the
pointer at the cold-fill pressure. This will help to identify future
loss of pressure due to leaks"

That's it.

I guess this refers to the red pointer which you can set yourself to
indicate the pressure when cold. Apart from that nothing. There are no
screws which indicate any adjustment.

The whole thing was bought as a kit and the gauge screws into the
pressure relief valve which in turn has the mains water connected to it
via a double check valve. The other side of it is tee'd into the main
CH flow just before the pump.

When I let the system fill the sound of the water flowing into the
system had reduced to being almost silent. This was when the PRD kicked
in and water started spraying out.

On 24 Dec 2005 07:34:08 -0800, wrote:

Just had another look at the instructions. The make is Altecnic.


Quite a commonly available one.


The only instructions referring to the pressure gauge say "Set the
pointer at the cold-fill pressure. This will help to identify future
loss of pressure due to leaks"

That's it.

I guess this refers to the red pointer which you can set yourself to
indicate the pressure when cold. Apart from that nothing. There are no
screws which indicate any adjustment.

The whole thing was bought as a kit and the gauge screws into the
pressure relief valve which in turn has the mains water connected to it
via a double check valve. The other side of it is tee'd into the main
CH flow just before the pump.

When I let the system fill the sound of the water flowing into the
system had reduced to being almost silent. This was when the PRD kicked
in and water started spraying out.

That's expected behaviour. I'm pretty sure that the gauge is duff.



--

..andy

"Sadly" wrote in message
oups.com...

wrote:

Just converted my CH system to sealed but when I fill with water
nothing is registering on the pressure gauge.

I have left the incoming mains on until the pressure relief valve goes
off (indicating 3bar) and still absolutely nothing registering on the
pressure gauge.

Water is peeing across the room when I let water out of the radiator
vents!

I removed the gauge from the expansion vessel and the back of the gauge
has a hole in. Should it have a pin sticking out of it rather than a
hole ?

I removed the front cover of the gauge and the needle pings back to 0
if I gently push it so I don't think it is stuck.

Can anyone confirm my diagnosis. The fact that the PRD goes off must
mean I have reached 3 bar ?

Do these devices usually fail or could I have damaged it when fitting
it ?

Can you buy replacements seperately ?

TIA for any help.

Isn't the gauge on the expansion vessel for telling you what pressure
the gas in the expansion vessel is at, not the water in the system? If
there is no gas I would expect it to read 0 whatever pressure the water
was at.

I may well be wrong though...


You are!

To the OP yes pressure gauges can and do fail. It sounds as though yours has
a blocked connecting port or it could ba a blockage in the gauge itself.
Does water weep out when you loosen the gauge from the socket?

John wrote:
"Sadly" wrote in message
oups.com...

wrote:

Just converted my CH system to sealed but when I fill with water
nothing is registering on the pressure gauge.

I have left the incoming mains on until the pressure relief valve goes
off (indicating 3bar) and still absolutely nothing registering on the
pressure gauge.

Water is peeing across the room when I let water out of the radiator
vents!

I removed the gauge from the expansion vessel and the back of the gauge
has a hole in. Should it have a pin sticking out of it rather than a
hole ?

I removed the front cover of the gauge and the needle pings back to 0
if I gently push it so I don't think it is stuck.

Can anyone confirm my diagnosis. The fact that the PRD goes off must
mean I have reached 3 bar ?

Do these devices usually fail or could I have damaged it when fitting
it ?

Can you buy replacements seperately ?

TIA for any help.

Isn't the gauge on the expansion vessel for telling you what pressure
the gas in the expansion vessel is at, not the water in the system? If
there is no gas I would expect it to read 0 whatever pressure the water
was at.

I may well be wrong though...


You are!

To the OP yes pressure gauges can and do fail. It sounds as though yours has
a blocked connecting port or it could ba a blockage in the gauge itself.
Does water weep out when you loosen the gauge from the socket?

OK, I'm more than willing to accept when I am wrong ;-)

In an earlier contribution to this discussion,
wrote:

Also forgot to add that I checked the pressure on the air side of the
expansion vessel and it measured 22 psi which is 1.5 bar. This agrees
with the pre-charge details on the side of the vessel.

So far the system has only been run on cold as the gas has not been
connected to the boiler yet.

That sounds awfully high to me. The usual rules of thumb are these:
* Air charge pressure with water system unpressurised: 0.7 bar (10 PSI)
* Water pressure cold: 1 bar
* Water pressure hot: ~2 bar

The water pressure when cold needs to be *higher* than the air charge
pressure, so that the air in the expansion vessel is further compressed a
bit when the water system is pressurised. If this is not so, it only needs
the slightest leak - or a bit of air bled out - in the water system for all
pressure to be lost. If the cold pressure is too high, there's not enough
margin for expansion before the safety valve blows.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
wrote:

Also forgot to add that I checked the pressure on the air side of the
expansion vessel and it measured 22 psi which is 1.5 bar. This agrees
with the pre-charge details on the side of the vessel.

So far the system has only been run on cold as the gas has not been
connected to the boiler yet.

That sounds awfully high to me. The usual rules of thumb are these:
* Air charge pressure with water system unpressurised: 0.7 bar (10 PSI)
* Water pressure cold: 1 bar
* Water pressure hot: ~2 bar

The water pressure when cold needs to be *higher* than the air charge
pressure, so that the air in the expansion vessel is further compressed a
bit when the water system is pressurised. If this is not so, it only needs
the slightest leak - or a bit of air bled out - in the water system for
all pressure to be lost. If the cold pressure is too high, there's not
enough margin for expansion before the safety valve blows.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

I thought extactly the same - I will normally recharge an expansion vessel
(remembering to keep an open end) to around 0.7 bar, then water pressure
cold: 1bar - 1.5 bar, depending upon boiler.

Angus