Greenstar HE Plus 35 Combi - How do i top up central heating

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Having moved into a new house in the summer with a Greenstar HE plus combi boiler, I decided to bleed the radiators. The pressure, which was at 1 bar has now dropped down to well below 1 bar. Hoe do I top up the boiler. There is what I think is called a filling loop at the side of the boiler with a flexible pipe. Can anyone help please
Thanks, Nigel
 
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There will usually be a pipe connecting the cold main to the central heating return. At one end of the pipe(usually braided flexible) there will be an isolation valve (either thumb tap or ballofix type, which you will need a flatblade screwdriver for). At the other end there will be exactly the same with a non return valve built in (longer chrome tap).
Open both valves until pressure increases to between 1 and 1.5 bar, then close both valves.

Hope this helps
 
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Thanks for advice. I opened both valves for quite a long time. I could here water flowing but pressure has still not moved. The radiators that needed bleeding did each take about 60 seconds + until I got water from them. Do I need to wait for pump to start working for pressure to rise or should it happen as soon as I put water in? I have checked all the radiators for leaks and all are dry. Thanks Nigel
 
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The pressure should rise regardless whether the boiler is on or off, however on some boilers if the diverter valve on the boiler is in the hot water position the pressure will increase slightly when you switch the heating on. Give it a try it wont do any harm, you may hear a hiss from the boiler as there is an auto air vent on the boiler which may bleed itself if the boiler has bee emptied, this is quite normal. Check the PRV pipe outside isn't dripping as this would cause the boiler to loose pressure.
 
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Thanks for that - I have persevered and the pressure is now at 1.5 bar - so I can continue bleeding the radiators and top up system as required. Thanks for your help.
 

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