I have a Saunier Duval ISOFAST 28 E whose pressure varies from 2.4bars
(when on) to 0.4 bars (when off for some time). I have to frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance

In an earlier contribution to this discussion,
Eithera wrote:

I have a Saunier Duval ISOFAST 28 E whose pressure varies from 2.4bars
(when on) to 0.4 bars (when off for some time). I have to frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance

It's probably lost some of its air - and thus reduced its expansion
capacity - causing the pressure to rise too much, and water to be expelled
through the pressure relief valve.

With the water system unpressurised, you should have something like 0.7 bar
(10 psi) on the air side of the pressure vessel. There should be a Schrader
valve (like a car tyre valve) where you can measure the pressure and pump
more air in. If this is low, top it up to 0.7 bar and then pressurise the
water system to 1 bar when cold. Hopefully it won't then rise above 2 bar
when hot.

Note: If water comes out of the Schrader valve, the vessel has a split
diaphragm, and is shot.
--
Cheers,
Set Square
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On Tue, 23 Nov 2004 07:07:07 -0800, Eithera wrote:

I have a Saunier Duval ISOFAST 28 E whose pressure varies from 2.4bars
(when on) to 0.4 bars (when off for some time). I have to frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance

See FAQ.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

(Eithera) wrote in message . com...
I have a Saunier Duval ISOFAST 28 E whose pressure varies from 2.4bars
(when on) to 0.4 bars (when off for some time). I have to frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance
Hi, If there is no sign anywhere of a leak, remove the boiler cover,
you will see the pump on the left, about 2in to the left of the pump
is a flat red metal expansion vessel. Fitted to it is a "Tyre Inflater
valve" Press this in with a match, if water comes out it has failed.
You dont have to renew it, as that is a nightmare job, instead obtain
an expansion vessel (1 to 3 L) from plumbCentre and fit it in the
return line near the boiler.
If nothing comes out, use a car foot pump to inflate it to 2 Bar
(25psi)
If that works but only for a few days, replace the "Tyre inflater
valve" (50p from Halfords)
Regards
Bob

On Tue, 23 Nov 2004 13:20:44 -0800, bob wrote:

(Eithera) wrote in message . com...
I have a Saunier Duval ISOFAST 28 E whose pressure varies from 2.4bars
(when on) to 0.4 bars (when off for some time). I have to frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance
Hi, If there is no sign anywhere of a leak, remove the boiler cover,
you will see the pump on the left, about 2in to the left of the pump
is a flat red metal expansion vessel. Fitted to it is a "Tyre Inflater
valve" Press this in with a match, if water comes out it has failed.
You dont have to renew it, as that is a nightmare job, instead obtain
an expansion vessel (1 to 3 L) from plumbCentre and fit it in the
return line near the boiler.

That would likely be far too small.
See FAQ.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

"Ed Sirett" wrote in message on.co.uk...
On Tue, 23 Nov 2004 13:20:44 -0800, bob wrote:

(Eithera) wrote in message . com...
I have a Saunier Duval ISOFAST 28 E whose pressure varies from 2.4bars
(when on) to 0.4 bars (when off for some time). I have to frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance
Hi, If there is no sign anywhere of a leak, remove the boiler cover,
you will see the pump on the left, about 2in to the left of the pump
is a flat red metal expansion vessel. Fitted to it is a "Tyre Inflater
valve" Press this in with a match, if water comes out it has failed.
You dont have to renew it, as that is a nightmare job, instead obtain
an expansion vessel (1 to 3 L) from plumbCentre and fit it in the
return line near the boiler.

That would likely be far too small.
See FAQ.

OK! so use one a Litre bit bigger then

bob wrote:
(Eithera) wrote in message
. com...
I have a Saunier Duval ISOFAST 28 E whose pressure varies from
2.4bars
(when on) to 0.4 bars (when off for some time). I have to
frequently
fill in. Sounds like the vessel is packing up. Any idea what is the
normal life of a vessel and what causes its failure? Many thanks in
advance
Hi, If there is no sign anywhere of a leak, remove the boiler cover,
you will see the pump on the left, about 2in to the left of the pump
is a flat red metal expansion vessel. Fitted to it is a "Tyre
Inflater
valve" Press this in with a match, if water comes out it has failed.
You dont have to renew it, as that is a nightmare job, instead obtain
an expansion vessel (1 to 3 L) from plumbCentre and fit it in the
return line near the boiler.
If nothing comes out, use a car foot pump to inflate it to 2 Bar
(25psi)
If that works but only for a few days, replace the "Tyre inflater
valve" (50p from Halfords)
Regards
Bob

Bob

Many thanks for a very helpful reply. I presume that the new vessel
comes fully pressurised. Do I have to do some adjustments after
replacing the vessel@

Kind regards
Eithera

Unlikely. My comiserations on your having a Saunier Duval bye the way.