Rad Temps CH pressure

29 Jun 2005
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United Kingdom

Just noticed the rad up stairs in the back bedroom onl luke warm, bled it and 90% was air :confused:

Had every rad off in house last year when I plastered the place and moved a lot of the pipe work, thought I had got rid of all the air but every so often the pressure drops on the combi down to around a bar, so I top it back up. could this just be pockets of air in the system moving around causing the pressure drop?

When I bled the rad up stairs the pressure went down to 0!! having air in one rad would this make the whole system under perform? i.e. having to put the CH temp up on the combi to make rooms warm or would that just be the room with the air lock?

Just bled all rads, was only two up stairs that had air, mainly the back room.

I always try to have the combi pressure on 1.5 bar ( wish my turbo on my car could run that :cool: ) is this about right? its a Ariston microGenus HE 32.

I know its colder outside, but just wondered bout the pressure if its lower than 1.5 bar say 1bar would the system not perform/ warm up as good as 1.5bar?


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Anywhere between 1 and 1.5 bar is ok.
Some boilers won't work at all if the pressure is below 0.7 bar (britony combi 80 etc)
Yeah the Ariston is like that if it gets below .7 it shuts off giving an error code.


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You should be able to keep bleeding the system and topping the pressure back up to 1bar. The manual will tell you the ideal running pressure, but my Baxi works down to less than 0.5bar with it's safe level is actually 1-2.5bar.

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