Hi All

I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement.
Close to the boiler, on one of the vertical water pipes, there is a little
valve. I assume it's a pressure relief valve. Over the last month or so, it
has started to weep. Just a drop or two every week or so.
Does this indicate a problem that is more severe than just a failing relief
valve, and if so, what tests can be made?

On Tue, 12 Dec 2006 10:57:27 -0000, "Grumps"
wrote:

Hi All

I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement.
Close to the boiler, on one of the vertical water pipes, there is a little
valve. I assume it's a pressure relief valve. Over the last month or so, it
has started to weep. Just a drop or two every week or so.
Does this indicate a problem that is more severe than just a failing relief
valve, and if so, what tests can be made?

A picture would be useful to decide what it is.

If it is a relief valve then it may be a simple spring and piston
thing that can be dismantled and examined.

In an earlier contribution to this discussion,
Grumps wrote:

Hi All

I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement.
Close to the boiler, on one of the vertical water pipes, there is a
little valve. I assume it's a pressure relief valve. Over the last
month or so, it has started to weep. Just a drop or two every week or
so. Does this indicate a problem that is more severe than just a failing
relief valve, and if so, what tests can be made?

It's very unlikely to be a pressure relief valve - 'cos there's no pressure
to speak of in an open vented system. More likely to be an automatic air
bleed valve or somesuch. A picture would be useful!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Roger Mills wrote:
In an earlier contribution to this discussion,
Grumps wrote:

Hi All

I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement.
Close to the boiler, on one of the vertical water pipes, there is a
little valve. I assume it's a pressure relief valve. Over the last
month or so, it has started to weep. Just a drop or two every week or
so. Does this indicate a problem that is more severe than just a
failing relief valve, and if so, what tests can be made?

It's very unlikely to be a pressure relief valve - 'cos there's no
pressure to speak of in an open vented system. More likely to be an
automatic air bleed valve or somesuch. A picture would be useful!

Ta. OK. I'll post a picture (somewhere) tonight.

In article ,
Grumps wrote:
I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement. Close to the boiler, on one of the vertical water pipes,
there is a little valve. I assume it's a pressure relief valve. Over
the last month or so, it has started to weep. Just a drop or two every
week or so. Does this indicate a problem that is more severe than just a
failing relief valve, and if so, what tests can be made?

Is it at the end of a pipe? If so, sounds like what's called an 'air
bottle' - an automatic vent. There are different types, but some have a
manual valve on the top to seal them after they've done what's needed at
initial fill. Check that is tight.

--
*You can't have everything, where would you put it?*

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

Dave Plowman (News) wrote:
In article ,
Grumps wrote:
I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement. Close to the boiler, on one of the vertical water pipes,
there is a little valve. I assume it's a pressure relief valve. Over
the last month or so, it has started to weep. Just a drop or two
every week or so. Does this indicate a problem that is more severe
than just a failing relief valve, and if so, what tests can be made?

Is it at the end of a pipe? If so, sounds like what's called an 'air
bottle' - an automatic vent. There are different types, but some have
a manual valve on the top to seal them after they've done what's
needed at initial fill. Check that is tight.

Ta.
No, it's inline.
I'll post a piccy.

"Grumps" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Grumps wrote:
I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement. Close to the boiler, on one of the vertical water pipes,
there is a little valve. I assume it's a pressure relief valve. Over
the last month or so, it has started to weep. Just a drop or two
every week or so. Does this indicate a problem that is more severe
than just a failing relief valve, and if so, what tests can be made?

Is it at the end of a pipe? If so, sounds like what's called an 'air
bottle' - an automatic vent. There are different types, but some have
a manual valve on the top to seal them after they've done what's
needed at initial fill. Check that is tight.

Ta.
No, it's inline.
I'll post a piccy.

By popular demand;
http://i10.tinypic.com/2ryir0o.jpg
Any ideas?
TIA

On Tue, 12 Dec 2006 19:01:21 -0000, Grumps wrote:

By popular demand;
http://i10.tinypic.com/2ryir0o.jpg
Any ideas?

Is that a spring visible in the end? It's not any of the normal (modern)
automatic air vent valves but that doesn't mean it isn't one. Seems a bit
daft to have in on a T in a vertical pipe for an air vent but then
plumbers are not the brightest of people at time...

What happens if you gently and slowly unscrew the cap? Have some old
towels underneath, the chances are this is in the primary and the water
in there is most likely black and stains anything. If it is an air vent I
suspect a small bit of crud has got into the seat and is keeping it just
a tiny bit open.

--
Cheers
Dave. pam is missing e-mail

Dave Liquorice wrote:
On Tue, 12 Dec 2006 19:01:21 -0000, Grumps wrote:

By popular demand;
http://i10.tinypic.com/2ryir0o.jpg
Any ideas?

Is that a spring visible in the end?

It looks like a spring.

It's not any of the normal
(modern) automatic air vent valves but that doesn't mean it isn't
one.

What is an air vent valve used for? Is it supposed to automatically remove
trapped air?

Seems a bit daft to have in on a T in a vertical pipe for an air
vent but then plumbers are not the brightest of people at time...

Indeed!

What happens if you gently and slowly unscrew the cap? Have some old
towels underneath, the chances are this is in the primary and the
water in there is most likely black and stains anything.

Hmm. I bet if I started to unscrew it nothing would happen, then, whoosh,
all my lovely dirty hot water flooding my kitchen.

If it is an
air vent I suspect a small bit of crud has got into the seat and is
keeping it just a tiny bit open.

If it's not a safety issue, then my feeling is to leave it alone.
Thanks BTW.

David Hansen wrote:
On Wed, 13 Dec 2006 09:53:55 -0000 someone who may be "Grumps"
wrote this:-

What is an air vent valve used for?

To vent air from the system.

Is it supposed to automatically remove trapped air?

If it is an automatic air vent. However, these sometimes stop
working.

A manual air vent needs to be operated from time to time. However,
not everyone knows or cares why they are fitted.

This gadget looks like an air vent, probably automatic, but it is
fitted in the wrong place. It should be at the top of a vertical
piece of pipe, called an air bottle, in which the air gathers before
release.

I do have a manual bleed screw at the top of a vert piece of pipe. I open
this from time to time, never very much air, and the water looks clean
(well, I guess it would do at the top of the circuit).

If it's not a safety issue, then my feeling is to leave it alone.

A good idea.

Thanks.

On Wed, 13 Dec 2006 09:53:55 -0000 someone who may be "Grumps"
wrote this:-

What is an air vent valve used for?

To vent air from the system.

Is it supposed to automatically remove trapped air?

If it is an automatic air vent. However, these sometimes stop
working.

A manual air vent needs to be operated from time to time. However,
not everyone knows or cares why they are fitted.

This gadget looks like an air vent, probably automatic, but it is
fitted in the wrong place. It should be at the top of a vertical
piece of pipe, called an air bottle, in which the air gathers before
release.

If it's not a safety issue, then my feeling is to leave it alone.

A good idea.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

In article ,
Grumps wrote:
Is that a spring visible in the end?

It looks like a spring.

It's not any of the normal
(modern) automatic air vent valves but that doesn't mean it isn't
one.

What is an air vent valve used for? Is it supposed to automatically
remove trapped air?

Yes - although that doesn't look like one. They usually have a float
operating the valve - the principle being that only water will close it.

--
*Why isn't there mouse-flavoured cat food?

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

On Tue, 12 Dec 2006 19:01:21 +0000, Grumps wrote:

"Grumps" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Grumps wrote:
I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement. Close to the boiler, on one of the vertical water pipes,
there is a little valve. I assume it's a pressure relief valve. Over
the last month or so, it has started to weep. Just a drop or two
every week or so. Does this indicate a problem that is more severe
than just a failing relief valve, and if so, what tests can be made?

Is it at the end of a pipe? If so, sounds like what's called an 'air
bottle' - an automatic vent. There are different types, but some have
a manual valve on the top to seal them after they've done what's
needed at initial fill. Check that is tight.

Ta.
No, it's inline.
I'll post a piccy.

By popular demand;
http://i10.tinypic.com/2ryir0o.jpg
Any ideas?
TIA

It's an early version of a pressure relief valve.
They are usually fitted if the vent pipe from the boiler does not
continually rise.

You will need to drain the system to repair it, when I tried to
repair one I was not been successful and had to replace it.

If you can live with a very small leak that might be the best solution as
the heating system is probably up for a major overhaul soon anyway.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

"Ed Sirett" wrote in message
...
On Tue, 12 Dec 2006 19:01:21 +0000, Grumps wrote:

"Grumps" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Grumps wrote:
I've got a 25 year old Potterton gas boiler. Open vented, Y-plan
arrangement. Close to the boiler, on one of the vertical water pipes,
there is a little valve. I assume it's a pressure relief valve. Over
the last month or so, it has started to weep. Just a drop or two
every week or so. Does this indicate a problem that is more severe
than just a failing relief valve, and if so, what tests can be made?

Is it at the end of a pipe? If so, sounds like what's called an 'air
bottle' - an automatic vent. There are different types, but some have
a manual valve on the top to seal them after they've done what's
needed at initial fill. Check that is tight.

Ta.
No, it's inline.
I'll post a piccy.

By popular demand;
http://i10.tinypic.com/2ryir0o.jpg
Any ideas?
TIA

It's an early version of a pressure relief valve.

Thanks. I thought it might've been.

They are usually fitted if the vent pipe from the boiler does not
continually rise.

Well, it has got some horizontal sections.

You will need to drain the system to repair it, when I tried to
repair one I was not been successful and had to replace it.

System was drained in the spring. Quite clean water, but I'm sure there's a
lot more sludge in there.

If you can live with a very small leak that might be the best solution as
the heating system is probably up for a major overhaul soon anyway.

Indeed. I think I'll leave it for now.
Ta.