My water pressure on my combi-boiler was low (less than 1) , and so I let in some more (up to about 2.5). However, once I turned the radiators on, it seems to have shoot up to over 3.
Is this correct/wrong/ and should I correct it? If so, how...should I just bleed the radiators a bit, or is it simply because when the water gets hot it expands thus creating a natural increase in water pressure?
Many thanks for any advice (greatfully recieved)!!
"veronica brown" wrote | My water pressure on my combi-boiler was low (less than 1) , and so | I let in some more (up to about 2.5). However, once I turned the | radiators on, it seems to have shoot up to over 3. | Is this correct/wrong/ and should I correct it? If so, how...should | I just bleed the radiators a bit, or is it simply because when the | water gets hot it expands thus creating a natural increase in water | pressure? | Many thanks for any advice (greatfully recieved)!!
It's because it gets hot and expands.
Pressure is usually 1-1.5 cold and no more than 3 hot, but check your boiler manual (or post details here). 2.5 cold sounds a bit too high.
Hello,
Yesterday I noticed that the water pressure in my combi-boiler was below 1, so I let in some more water upto about 2.5. However, when I turned the central heating on it went up to over 3 and it has stayed there. Can anyone tell me, is this dangerous? Can I use the heating? Should I reduce it a little by bleeding a radiator?
Thanks Justin
See FAQ on Selaed CH below. The pressure releif valve must be just on the point of opening. Bleeding all radiators migth bring it down and letting some out a drain point certainly will. Look for about 1.5 bar max.
Generally speaking, if you live in not abnormally tall house, the pressure should be set to 1 bar when cold. When hot, the water will expand, increasing the pressure. This pressure rise should be limited to 0.5 bar, although some people will design systems with up to 1 bar increase. If the increase in pressure when hot exceeds this, then you have a knackered or missing expansion vessel, which needs sorting.
If the gauge ever reads much above 3, then you have probably got (hopefully) a knackered pressure gauge, or (dangerously and more likely) a broken pressure relief valve, which is designed to open around 3 bar and chuck your system's contents outside the house.
Christian.
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