G
Glosguy
I have a 10 year old Worcester-Bosch Greenstar 30 HE combi running 7 radiators in a 3 bedroom semi. All pipework and radiators were new with boiler.
Even after putting pressure back up to 1 to 1.5 bar while cold, I find within an hour or so it’s back to zero. The heating system seems to run OK even with boiler pressure showing zero. When I try to bleed a radiator nothing comes out, presumably because of the lack of pressure.
From reading forum posts I understand I need to find out whether the leak is in the pipework/radiator system or in the boiler. I can find no signs of leakage in any visible pipework or radiators.
Regarding the boiler check, I have read on forums that I should re-pressurise the boiler, then close down the CH out and return valves overnight to check whether it’s a boiler problem . If it’s a boiler problem I gather the pressure will be lost. If it’s a leak, the overnight pressure will stay the same. Is this correct?
See attached photo of pipework below boiler.
Question 1: what tool do I need to turn off the CH out and return valves (far left and far right in photo) please? Is it a normal allen key in the centre of the square ?
Question 2: One of the downstairs radiators is warm at the top and the bottom 70% is cold. Could the boiler pressure problem be the reason for the cold radiator bottom? Hopefully it’s not sludge after only 10 years. A sticker on the boiler says Sentinel x100 was put in in Year 2
Question 3: Due to continually having to top-up the pressure, will the protective benefit of the original Sentinel X100 now be lost and so need replacing? Is this a simple job, or do I need to get someone in to do this? If it’s easy, where is it put in?
Many thanks!

Even after putting pressure back up to 1 to 1.5 bar while cold, I find within an hour or so it’s back to zero. The heating system seems to run OK even with boiler pressure showing zero. When I try to bleed a radiator nothing comes out, presumably because of the lack of pressure.
From reading forum posts I understand I need to find out whether the leak is in the pipework/radiator system or in the boiler. I can find no signs of leakage in any visible pipework or radiators.
Regarding the boiler check, I have read on forums that I should re-pressurise the boiler, then close down the CH out and return valves overnight to check whether it’s a boiler problem . If it’s a boiler problem I gather the pressure will be lost. If it’s a leak, the overnight pressure will stay the same. Is this correct?
See attached photo of pipework below boiler.
Question 1: what tool do I need to turn off the CH out and return valves (far left and far right in photo) please? Is it a normal allen key in the centre of the square ?
Question 2: One of the downstairs radiators is warm at the top and the bottom 70% is cold. Could the boiler pressure problem be the reason for the cold radiator bottom? Hopefully it’s not sludge after only 10 years. A sticker on the boiler says Sentinel x100 was put in in Year 2
Question 3: Due to continually having to top-up the pressure, will the protective benefit of the original Sentinel X100 now be lost and so need replacing? Is this a simple job, or do I need to get someone in to do this? If it’s easy, where is it put in?
Many thanks!
