Correct pressure and bleeding on a Combi?

My Worcester 28CDi RSF has a minimum pressure level of 1bar indicated on the pressure gauge.
What should the optimum pressure be? When should I re-pressurise the system? When it falls below 1bar cold or hot?
Also should I only bleed the rads with the boiler powered down, powered up but not burning or while it's heating?
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Richard Markham

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OK to answer my own post, I have got the installation manual now!
1 bar is the correct cold pressure.
2.5 bar is the max test pressure when cold.
I'm still not sure if it's best to bleed rads hot or ocld, with or without the pump running.
--
Richard Markham

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hot or cold makes any difference, it is more comfortable on the fingers to do it cold.
--
Tim Mitchell

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On a traditional system, definitely when stopped, as it can easily suck air (and frequently does). On a pressurised system at 1 bar, the 0.5 bar or so maximum head of the pump will ensure that every valve will blow rather than suck, so you can be lazy and not bother going downstairs to turn it off, like you should!
Christian.
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