I tried to look in old post but can't find any information so I am
asking.

At this time of the year I am turning on the heating in my flat only
for couple of hour's in the bath room. All the radiators in the flat
are off.

The pressure on the boiler is low than normal about 0.7.
I know that when the hating is on it needs to be around 1.5 but isn't
the fact that only on radiator is on actually mean less hot water in
the system and there for less extract which mean lower pressure ? If I
top up the system and open more radiators the pressure goes very high
2.5.

Thank you for any information

On 16 May 2007 06:40:29 -0700 Golan wrote :
The pressure on the boiler is low than normal about 0.7.

That OK in a flat: 0.7 is about 20ft head which is a lot more than you'd
have with a header tank in the flat. Some boilers will cut out if the
static pressure cold drops below 0.5/0.6

I know that when the hating is on it needs to be around 1.5

No, it will rise when the system heats up, but there is no minimum
figure. If you had a big expansion vessel it might rise to 0.8 and that
would be fine. In a flat the concern would be if was rising to 2 or
more.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

In an earlier contribution to this discussion,
Golan wrote:

I tried to look in old post but can't find any information so I am
asking.

At this time of the year I am turning on the heating in my flat only
for couple of hour's in the bath room. All the radiators in the flat
are off.

The pressure on the boiler is low than normal about 0.7.
I know that when the hating is on it needs to be around 1.5 but isn't
the fact that only on radiator is on actually mean less hot water in
the system and there for less extract which mean lower pressure ? If I
top up the system and open more radiators the pressure goes very high
2.5.

Thank you for any information

From distilling numerous previous threads, the 'norm' seems to be 1 bar when
cold and 2 bar when hot.

The pressure rise is due to the fact that the water in the system expands
when it gets hot and compresses the gas in the expansion vessel, with a
consequent increase in pressure. If only *some* of the water is getting hot
(the remainder being in unheated radiators and pipes) the pressure rise will
be lower. What you are experiencing seems fairly normal - except that 0.7
bar sounds a bit low. Is that cold or (partially) hot?
--
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!

In message . com, Golan
writes
I tried to look in old post but can't find any information so I am
asking.

At this time of the year I am turning on the heating in my flat only
for couple of hour's in the bath room. All the radiators in the flat
are off.

The pressure on the boiler is low than normal about 0.7.
I know that when the hating is on it needs to be around 1.5 but isn't
the fact that only on radiator is on actually mean less hot water in
the system and there for less extract which mean lower pressure ? If I
top up the system and open more radiators the pressure goes very high
2.5.

Thank you for any information

Have you been drinking fernox ?

Quite simply, either there is sufficient pressure, or the boiler won't
work

That's all

--
geoff

On Wed, 16 May 2007 06:40:29 -0700, Golan wrote:

I tried to look in old post but can't find any information so I am
asking.

At this time of the year I am turning on the heating in my flat only
for couple of hour's in the bath room. All the radiators in the flat
are off.

The pressure on the boiler is low than normal about 0.7.
I know that when the hating is on it needs to be around 1.5 but isn't
the fact that only on radiator is on actually mean less hot water in
the system and there for less extract which mean lower pressure ? If I
top up the system and open more radiators the pressure goes very high
2.5.

Thank you for any information

See FAQ ( Sealed CH)
--
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