I have just bought a shower (not an electric one} that says it needs bar pressure of at least 1.5 We have a combi boiler but the pressure upstairs isn't that great. How can I measure it Thanks
As a rule of thumb: put the palm of your hand over the tap spout and if you can stop the flow of water then the pressure is low. If on the other hand you cannot stop the water then you have no problems.
If you buy a thermostatic shower you must make sure that it is designed for use on a combi system, other words you are left with a shower that will not opperate to maximum efficiency.
get the water board to come out and do a pressure and flow test free of charge. Its not always the pressure which is a problem it can also be the flow due to old lead pipes or being on a shared pipe. You should have more than 1.5 bar, as this is the minimum water companies are obliged to supply. i would say you would have at least 2.5 at a rough guess. phone them up say you have a poor supply and insist they come out, Tell them it is a long standing problem