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Worcester Bosch 35CDi II Combi - low water pressure

Postby John.Smith » Sat Jun 12, 2010 8:53 pm

My boiler has water pressure below one bar. Can this be increased by altering one of the valves on the under side of the boiler? I'm sure I changed it some time ago but the instruction booklet doesn't give that advice.
Yours sincerely John Smith
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Simply Build It

Postby htg engineer » Sun Jun 13, 2010 7:05 pm

If you mean system pressure - then you would normally have a white plastic key for filling the system. Insert and 1/2 turn then open grey thumb screw valve.

If the system is working and all radiators heat to the top - then leave it - it'll work below 1 bar.

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Postby John.Smith » Sun Jun 13, 2010 7:37 pm

Dear "htg engineer", thank you very much for your swift & accurate response. I'll give this a try. Thank you.
Yours sincerely John smith.
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Postby bigbarney » Fri Oct 15, 2010 6:48 pm

i have a worcester cd35i ii combi boiler which now has created a problem
the pressure of the unit is just over 1 bar and when you turn either the central heating or the hot water all goes well the relevant lights come on and the pilot light kicks in and it all fires up, the pressure slowly raises to 1.5bar then you get a knocking noise as if it has a air lock and the pressure shouts up to just over 2 bar and the needle waves about until it switches all off and end up with just the green on light
i've gone round all the radiators and bled them all,
the boiler was fitted in 2004 and had no proplem with it until now, is the problem something simple i could reset or replace or is it a engineer callout
many thanks
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