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On Tue, 19 Oct 2004 18:34:45 GMT, (DaveŁ) wrote:
On Tue, 19 Oct 2004 10:47:24 +0100, "Christian McArdle"
wrote:
The pressure relief valve however, has expelled more water and now the
system is down to 0.8 bar according to the guage. (It was 2.0 bar when
I toppd up the pressure just 5 hours ago).
How much does the pressure rise when between cold and hot? If the pressure
rise is 1 bar, then the expansion vessel is either shot or undersized. It
is better to calculate a system that only gives = 0.5 bar rise and
pressurise to 1 bar when cold. With 3 storeys, the design should be more
specific and will depend on the relative vertical locations of the
components.
I suspect that if you have a system that rises 1 bar and starts at 2 bar
cold, then it will be activating the pressure relief, which may depressurise
the system considerably. The fix is to repair/add an additional vessel (if
required) and set to 1 bar cold.
Funnily enough, the system seems to be working fine since I finished
the work on it yeaterday, depite the odd symptoms I mentioned:
(pressure valve blowing at 2-bar instead or 3-bar, according to the
guage). When cold, the system, reads around 1 bar on the guage and
rises to about 2 bar when hot.
PS Slight correction: I looked at it at night, after the rads had
stoped heating and the pressure was down to almost 0-bar on the guage.
However it still fired up when I turned a hot tap on. I have now
topped up the pressure to 1 bar while it was relatively cool.
Dave L
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