High Boiler Pressure

[Devo1982]

Our boiler's idle pressure is approximately 2 bar, but this sharply rises to just over 3 when the heating is on full whack. I have read around various posts which say the system should dump its load when it gets to 3. Does this mean it's knackered or could it be something else?

It was fine up until a few weeks ago, but I have bled all the radiators since (as they weren't all getting fully warm) and then put more water into the system via the filling loop. Did I fill the system too high and/or are there other things I should check/try?

I did read somewhere that the fresh water will be releasing oxygen as it heats up therefore increasing the pressure, but how do I reduce this slightly?

The boiler is a Saunier Duval Thema F23E.

Thanks in advance...

 

[gas4you]

Try draining some water off and setting the pressure to 1 bar cold.

 

[Devo1982]

Try draining some water off and setting the pressure to 1 bar cold.

What's the easiest way to do this? Sorry - I am a bit of an amateur when it comes to boilers

 

[gas4you]

Drain cock, probably under one of the downstairs rads.

 

[Agile]

I went to a Keston today with similar problems.

It turned out that the Ausi installer had done all the paperwork perfectly but had forgotten to fit an expansion vessel or put the Tun dish within 500 mm of the T&P valve.

In this case the boiler's EXV may need recharging.

Horrible boilers the S-D.

Tony