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Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.: 445  Gauge pressure (also spelled gage pressure) is the pressure relative to the ambient pressure.
Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m2); similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and U.S. customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure, and the torr is defined as 1⁄760 of this. Manometric units such as the centimetre of water, millimetre of mercury, and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer.

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  1. M

    Central heating losing pressure all the time

    Every two weeks or so I have to go and top up the system because the hot taps are running cold. Boiler display is flashing 0.6 bar and I fill up to 1.3. I've had an engineer look inside the boiler and he can't see anything wrong. I've checked the pipes all over the house and cannot see any...
  2. L

    Toilet flush pressure question

    Hello, I have a question on flush pressure. When I press the bigger button, there's hardly a flush. I understand that's normal but it's a very minimal flush. And then the smaller button is quite hard to press and I think doesn't do a full flush either. So when I flush I press both and it works...
  3. M

    Aqualisa Shower Pressure Problem

    When I turn on the shower or bath, initially the pump runs (quite loudly) and only a trickle comes out. I have to alternate turning on the bath and shower before I get a reasonable flow. Then once it is running, if the water is at maximum temperature on the mixer it flows smoothly, but as soon...
  4. E

    Loss of Hot Water Pressure to Shower

    Looking for any ideas to help. I've a Heatrae Sadia Hot Water tank, heated through Oil fired boiler (working fine). A week ago I reset the air gap as I was having dripping from the pressure relief valve. Since then I've lost a lot of pressure from the hot water feed to my shower. The rest of...
  5. A

    Outside tap loss of pressure

    I’ve lost the pressure from the outside tap. It was working fine. I have checked the washer on the outside tap and the inside stop valve seen in the picture. Not sure what the thing is to the right of the stopcock? I’ve also taken the inners out of the outside tap and turned on the water again...
  6. T

    Hot water flow/pressure

    I recently had an eco tec plus 836 combi installed as part of an oil to gas conversion. One thing I can’t work out is why the bathroom sink hot water flow is 12-13L per minute with at 44c and even hotter. However the nearby bath freestanding tap is 8-9L per minute at this temp. Both taps...
  7. D

    Boiler pressure dropping to zero when heating turns off.

    Good afternoon, I am experiencing a pressure issue with my heating system and was hoping to receive additional insight as to what the problem could be. We have a biomass boiler and stratification tank set up and recently had an issue with boiler pressure dropping off when the system was cold...
  8. C

    Best place to source low pressure bath filler taps

    I'm having a nightmare trying to find matt black wall or deck mounted bath mixer taps with 3/4 fitting that work on 0.2 bar. From tank to tap, I have around 2.4 metres, so a pressure of a little over 0.2 bar. The flow measured from the tap currently fitted is 11 litres per minute. Pretty much...
  9. E

    gravity fed upstairs shower pressure question

    We have a gravity fed hot water system in our the house we have just recently moved into. It works fine with the downstairs shower, however we are about to upgrade the upstairs bathroom and are considering installing a shower bath. My concern is that although there is more than sufficient...
  10. M

    Gas pressure drop with flow to a larger pipe from a smaller one?

    Hi, Non-professional / knowledgeable person here. I'm a Brit in Romania who volunteers for a charity building an old peoples home for needy old people. Out here competence and integrity is harder to come by in a worker, in fact it's hard to find workers at all where we are in the countryside...
  11. L

    Worcester Bosch Heatslave Boiler pressure issue... any thoughts...?

    Greetings. I have an external Worcester Bosch Heatslave boiler and have a question about pressure. The boiler pressure was set to 1.5 during a recent visit by a plumber (as it seemed to have dropped and was hovering between the green and red zone) . A few days later I turned the thermostat down...
  12. surfsup

    Outside tap lost pressure since cold snap

    My outside tap has had really low pressure after the cold weather a few weeks ago. Its connected from under the kitchen sink, and can be isolated from turning a flat head screw type thing a quarter turn. Any help or advice would be much appreciated!
  13. G

    Problems with shower pressure

    I have just had a boiler, hot water tank and power shower pump replaced on advice by my plumber. I have two separate boilers, heat/hotwater systems in the house. This boiler was replaced by a combi boiler as it only heats the lounge and master bed and provides hot water to en-suite bathroom and...
  14. L

    Worcester Bosch Heatslave Boiler pressure issue...

    Greetings. I have an external Worcester Bosch Heatslave boiler and have a question about pressure. The boiler pressure was set to 1.5 during a recent visit by a plumber (as it seemed to have dropped and was hovering between the green and red zone) . A few days later I turned the thermostat down...
  15. D


    Can't check pressure on Boss pressure valve (big round red thing) because there is no gauge attached. Thanks
  16. S

    Low water pressure pumps not working

    Pumps and low pressure I moved the bathroom to the back the house (next room) upstairs. I put in two pumps because low pressure water area. One for shower and one for bath. They both work intermittently and I often need to get them started with a magnet! They were new pumps. In the shower the...
  17. angy101

    Water Pressure Shower

    Hi I moved into a property where the pressure is slightly low and they have this super duper shower but pressure is somewhat lacking. I have had water company out and they did do a check and they found the flow rate reduced but they mentioned about the inside stopcock/tap should be changed just...
  18. T

    Vaillant eco plus 837 System loosing pressure.

    I have a Vaillant eco plus 837, year installed 2008. It works well. We have one large zone for the house with 13 rads running off it. We also have an UFH zone in the kitchen. Near the boiler I have 2 port valves which control this part of the system. The boiler has been loosing pressure...
  19. M

    Baxi boiler pressure drops after heating

    Hi, we have a back combi heater. Whenever the heating comes on it seems to lose pressure within a few hours and I have to refill each morning. The boiler seems to function well, and the pressure only drops with the heating and not the water being on. Ie it started last winter and was then...
  20. hkgccf

    Boiler pressure problem - Baxi EcoBlue

    the pressure of my boiler looks unstable After i re-pressurize to 1.5 bar, using tap is ok without problem. but when turn on the central heating, the pressure rises over 2 and the error code 117 showing water pressure high After i did the bleeding and re-pressurize to 1.3 bar, the heating is...
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