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pressure

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. S

    Closed loop pressure increasing

    Just wondering if anyone has even seen an issue with the pressure gradually increasing on a closed loop system where there is no fill loop attached. I'm seeing this issue on a gshp and whats more unusual is its on the cooling side. If it was on the heating side you could put it down to expansion...
    • Shifters
    • Thread
    • closed expansion vessel pressure
    • Replies: 3
    • Forum: Renewable Energy
  2. E

    What boiler pressure loss is ok over time?

    My Ideal boiler pressure gauge pointer shows about 0.85 when cold (about 1.8 when the heating is on). 10 weeks ago the readings were 1.0 when cold and 2.0 when hot. Clearly there is a loss in pressure over time. I can see no leak on any radiator or near the boiler. Is this pressure drop of...
  3. M

    Pressure reducing valve - can I remove?

    As part of full house renovation, I've switched from a conventional boiler/gravity fed tank to a combi boiler. Under the old system I note that a pressure reducing valve has been fitted to the pipework feeding the shower mixer (assuming as mains cold overpowering the supply pressure from the...
  4. M

    Poor flow and pressure issues?

    Hi guys. I replaced an electric shower for a family member recently and on completion noticed how poor the pressure was. It wasn’t like this the week before when I initially looked at it. Apparently Severn Trent were in the area the following week to do some work. She’s now saying that the...
  5. A

    Not able to put pressure in vessel

    Had a main water leak lately and fixed it it had been there for a few days and the boiler wasn't working after the repair I tried to pressurize the vessel in the hot press but couldn't pump air in I took out the valve stem and inserted a blunt stick in but it wouldn't go in seems like it's...
  6. N

    Combi boiler loosing pressure fast

    Hi all, back again with yet another question about my grant vortex combi boiler 😩 Sorted all previous problems and was running sweet until recently… now it’s loosing pressure really quick, from 1.5 bar down to 0 in a couple of hours (even when on standby neither hot water or central heating...
    • Nathzy01
    • Thread
    • boiler combi fast loosing pressure
    • Replies: 5
    • Forum: Central Heating Forum
  7. N

    Pressure drop on test guage, nothing at meter

    Hi all, I am wondering if someone can make sense of this. I have been trying to determine if there is a leak on an existing water supply pipe. Attached a dry pressure guage to garden tap and turned tap on. Pressure went to about 3.5 bar then I shut off supply at the water meter. Over the next...
  8. C

    Pressure release valves

    Anyone finding these 'failing' early? I'm in Ireland and have never seen these valves opening under normal conditions. Recently, in the last year, I have had three brand new PRVs opening under normal conditions. One of them was on the mains supply which actually has a pressure reducing valve on...
  9. Dbutler929

    T80 Triton low pressure in morning

    Morning, We installed a t80 from a t90 in December as it was the only black shower they had. Its been a diasaster as the pressure in our area is not strong enough as it runs off the mains. We can't shower first thing in the morning usually after 9am is our best chance as it's always low...
  10. D

    Replaced shoer taps, lost a lot of pressure

    Hey all. Replaced the shower taps, and have lost a lot of pressure. Noticed the tap lengths are shorter than the other shower, wondering if i might have used basin taps.....would that have caused a big loss in pressure?
  11. C

    Leak hard to find - possible pressure issue?

    Hi all Totally new to this forum and hoping for some guidance. Two weeks ago we noticed a brown stain on our kitchen ceiling. Above it is the bathroom and airing cupboard where our hot water tank is. We have a closed system. The pressure had dropped on our boiler and so we topped it up (have...
  12. T

    New kitchen tap and low water pressure

    I recently installed a new kitchen tap which has slimmer flexi hoses to the previous tap. After installing it I noticed the water pressure has dropped everywhere in the house. If I turn the isolation valves for the kitchen tap off, the pressure returns to what it was previously. I don't...
  13. H

    Water pump pressure Issues..

    Greetings, newbie here, kindly seeking advice on a water pump issue I have. Before I get started, I'd like to mention that I'm a complete novice and have no prior experience with pumps or plumbing. Basically, I'm in the process of purchasing a home that is out in the sticks and has a 120ft...
  14. T

    URGENT Systemate3, anyone know how to release the pressure?

    Systemate3, anyone know how to release the pressure? Dial up in the red. Working fine but boiler fires up every 20 minutes to seemingly top up store.
  15. N

    Vaillant Atmotec exclusiv - no pressure

    Hi, I'm in an Airbnb in Austria and the boiler has lost pressure. YouTube seems to suggest it's an easy fix....but I can't find the valves that are used in the videos. Any clues from the photo?!
  16. michcosg

    Possible to push a push-fit fitting back on a pipe at 3 bar?

    Hi Folks I am considering a job in council block flat which involves amending 15mm copper pipework under 3 bar of pressure. The problem is the local council seem to a bit hard to get a hold of to turn off the water! Thus my plan was to freeze the pipe with an electrical freezing kit and do...
  17. J

    URGENT Pressure relief valve

    Hi, does.anyone know how long the pressure relief valve stays on for on a Greenstar Heatslave 1825? Thanks
    • Jumpinjenjen
    • Thread
    • pressure pressure relief valve relief
    • Replies: 3
    • Forum: Central Heating Forum
  18. P

    Cylinder noise / Balanced Colds / Pressure etc

    I wanted to start a new more dedicated thread as I am on about 3 just now in one way or another trying to get up to speed with my problem. The issue is that my Gledhill Stainless Lite indirect unvented cylinder makes loud noises when heating - this is a bit random, but that noise is loud enough...
  19. Elraoak

    Pressure Loss (new EV, PRV and dosed with F4)

    Have a large CH system, not sure the volume but a mix of column radiators and UFH means it's probably 250L or more. Runs on a Vaillant Ecotec 630 that's been OK for 7 years, but recently started losing pressure (needs topping up weekly). Had a new EV (old one was full of water apparently)...
  20. D

    House pressure reducing valve cold water hammer

    Having issues with water hammer, I have a megaflo with balanced hot / cold using a heat stadia 3 bar prv, this seems ok as getting 3 bar at taps with test gauge, the outside tap is between the house incoming stop valve and the 3 bar PRV and that is showing just over 4.5 bar. If I switch a hot...

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