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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. Sarah_Homeowner

    How do I Increase Pressure in my boiler??

    Hi, I am trying to increase the pressure in my gas boiler and was under the assumption it just involved opening these two small black valves. I have tried this but the pressure gauge on the boiler hasn't budged? Anyone know why this is?
  2. Jagobezzer

    HETAS - Without a pressure pump

    Hi all, Just a quick question. I have a log burner and a gas boiler on a dual fuel system (Central heating and Hot Water) either can do both. The hot water tank I believe is a closed system but is on the same level as the bath. Therefore as you might guess the water pressure at the bath even on...
  3. R

    Low pressure showing on boiler

    What the easiest way to find why my boiler is losing pressure. It is about 5 years old Vaillant combi boiler, we have just had 2 vertical radiator removed and refitted for decorating and now the pressure keeps dropping approx once a week. I guess a leak under the floor is possible, or trapped...
  4. chchris

    Solenoid valve and pressure valve

    Hi, guys! Hope you are all well. I have four solenoid valves connected to the main water supply, and they seem to break quite often. I believe it's the pressure that's causing this. I was thinking of adding a pressure valve to control the pressure before it goes through the solenoid valve. Do...
  5. P

    Working gas pressure on Vaillant ecotec 630

    British Gas servicing the above boiler ramped up the boiler to maximum in the installer menu to do flue gas analysis. They also measured the working gas pressure on the gas valve test nipple. This fell to 8mbar on maximum and 17mbar on high setting. They then removed the isolation valve under...
  6. Greenstar123

    Greenstar 30si compact filling link

    Hello all, I want to increase the system pressure to 1.5 bar. Following the user manual (found one online) and some YT videos the filling link should be clearly visible there, but I still cannot find the filling link on my Greenstar 30si compact, or at least nothing there looks like it. It...
  7. W

    Low hot water pressure

    Low hot water pressure Hi everyone, I'm hoping someone is able to shed some light on my situation before I have to call out the professionals. We've been in our house for over 3 years now, when we moved in the hot water pressure was pretty good (confirmed by a retired plumber family friend)...
  8. S

    Losing pressure heating

    Hi all not a plumber but am an engineer I have pressure drop in the system Worcester Bosch came back after repressureising the expansion vessel and he replaced the heat exchanger element. The boiler is coming up for 15 years old. The boiler was going below one bar and not increasing when...
  9. RenzoPan

    What is the pressure in this cylinder expansion vessel?

    I was told by the plumber to keep an eye on the pressure, to ensure it stays above 1.0. The red one is… but the black one is not…. What do the two mean?
  10. B

    Combi Boiler pressure refill?

    Hi, Just had a "Main Eco Compact" combi boiler installed as the Biasi one failed. It seems to work fine, gives a hot bath, i dont ever use the radiators or kitchen hot tap. (no point in upping the landlords gas bill for no reason) On day 4, the pressure is below 1. I filled it back up to >1, but...
  11. J

    Cant adjust Danfoss pressure am I using correct ports?

    I have a SIP space heater and fitted a new matching spec oil nozzle as part of a service on it. I wanted to check the pump pressure with the new nozzle and its difficult to be sure what port to connect to. And that these pumps are definitely adjustable! I turned an Allen screw which is not...
  12. S

    central heating unvented losing pressure

    Can central heating / gas engineer expert help me with below issue. During winter time only, I have been having issue with low pressure or pressure dropping with unvented hot water cylinder system. During summer time there is no usage of central heating so the pressure at unvented system is not...
  13. B

    How to balance water pressure in taps

    Hi everyone, Gas combi Boiler Mains fed in all taps and shower How do I balance the water pressure in all faucets in my flat. Every tap/water faucet is mains fed but the cold water is really strong in every tap that if I open the tap fully it flies out like a fountain but the hot water is not...
  14. D

    Boiler Losing Pressure Issue

    Hi, Looking to see if anyone can give some advice please. My Baxi boiler has been losing pressure and I am having to top it up approx. every 4 hours from 0-1.5 bar each time. This has been going on a week now. I have also started to notice small drips running down my condensate pipe...
  15. J

    Hot water element repaired without checking pressure?

    Hello, hoping someone can advise me. My boiler stopped working - no hot water or central heating. Called out a company who came and assessed the problem as being that the hot water element in the immersion tank needed replacing. (I don't know exactly what it is called as the company has still...
  16. J

    Is Pressure checked at same time of hot water cylinder repair

    Hello, hoping someone can advise me. My boiler stopped working - no hot water or central heating. Called out a company who came and assessed the problem as being that the hot water element in the immersion tank needed replacing. (I don't know exactly what it is called as the company has still...
  17. N

    Intergas Boiler pressure dropping

    Intergas Boiler (only 2 years old and serviced each year) pressure dropping to 0b after just 1hr of running - can anyone help? No leaks anywhere
  18. RedYellowLorry

    Worcester Keyless Filling Lever Not Moving

    Hello, I'm trying to top up the pressure on my Greenstar 30i ERP but the blue keyless filling lever won't move. It doesn't feel stiff, it feels as if it has been locked some how. Do I have to do something to get it to move? If anyone has any suggestions I would be very grateful. Thanks...
  19. W

    Pressure reliefe pouring out of unvented immersion heater.

    Hi all. So I have an OSO Super SXD 180 immersion heater and it is pouring a huge amount of water out of the cold water pressure relief valve regardless of whether the tank is heating or not. We're talking litres a minute currently. I have replaced the valve which changed nothing. I have...
  20. I

    Can I do anything to boost flow rate into my Roca cistern?

    Hello, First post, be gentle! Anyway, here's my issue. I have a Roca The Gap D-Trit close-couple toilet with integrated macerator in my secondary bathroom. In all it's a great solution for a problem location for a bathroom. However, the cistern has a typical european style side inlet pipe, and...
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