Recharge expansion vessel on CH

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Hi,

I am planning to recharge the expansion vessel on my central heating and need some information. I have heard people say that it has to be removed to recharge it. Is it right? Some others say that I have to drain the Central heating before I pressurise it if I don't remove it. I am confused now. What's the right way? I don't like to remove it completely.
 
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De-pressurise you boiler and leave drain cock open while you charge up your expansion vessel to that stated on data plate, normaly around 0.9 bar, close off drain cock, re-pressurise & vent system.
 
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Hi,

I am planning to recharge the expansion vessel on my central heating and need some information. I have heard people say that it has to be removed to recharge it. Is it right? Some others say that I have to drain the Central heating before I pressurise it if I don't remove it. I am confused now. What's the right way? I don't like to remove it completely.

Why are you doing this? What problem(s) are you having that leads you to believe this is a remedy?
 
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De-pressurise you boiler and leave drain cock open while you charge up your expansion vessel to that stated on data plate, normaly around 0.9 bar, close off drain cock, re-pressurise & vent system.

Thanks, I will follow your instructions.
 
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Why are you doing this? What problem(s) are you having that leads you to believe this is a remedy?

Checked it using my car tyre pressure reader, shows 0.8 bar whereas the vessel states 1.5 bar as factory fill pressure.
 
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Should be slightly below the cold fill pressure of your system. 1.5 may be the factory fill but it's unlikely to be suitable for a normal system. If you over pressurised it relative to the system pressure then even the smallest leak will lose too much pressure very quickly and shut down the boiler.
 
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Should be slightly below the cold fill pressure of your system. 1.5 may be the factory fill but it's unlikely to be suitable for a normal system. If you over pressurised it relative to the system pressure then even the smallest leak will lose too much pressure very quickly and shut down the boiler.

Thanks, now I understand. The system pressure currently stands slightly above 1 bar so I think 0.8 bar pressure in the expansion vessel is the right amount .
 
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Thanks, now I understand. The system pressure currently stands slightly above 1 bar so I think 0.8 bar pressure in the expansion vessel is the right amount .
Did you get 0.8 bar when the system was full (pressurised)? You should have around 0.9 when your system is de-pressurised, it makes a big difference.
 
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Normally charge them to 1 bar with water side depressurised on the basis you’ll lose 0.1 bar as you undo the pump connector ;)
 
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