prv or plv ?

[pw21]

Hi there,

Please can someone explain the difference between a pressure reducing valve and a pressure limiting valve ?

many thanks
Pete

 

[Paul Barker]

prv is a pressure relief valve. If the pressure gets too high for the particular application the prv discharges some water. Central heating systems are lablelled 3 bar but can go off from 2.5 bar upwards. If they fail to go off at 3 bar then the final safety device is that the cap blows off and we all get wet. That is a design feature. Other values of these valve exist for other applications.

plv is not an abbreviation I use. Maybe you are talking about a gosvenor or regulator.

 

[WDIK]

Hi there,

Please can someone explain the difference between a pressure reducing valve and a pressure limiting valve ?

many thanks
Pete

as Paul said there is no such acronym as PLV.

both devices you describe are known by the acronym PRV.

two entirely different devices though, one reducing pressure, for instance in a mains cold water feed.

the other is a safety valve designed to open at a predetermined set pressure.

 

[Deleted member 105431]

pressure reducing valves often found on unvented dhw cylinders regulate the flow pressure to say 3bar for example. Pressure limiting valves are a less accurate valve and limit the pressure normally to 5bar. Pressure relief valves (prv's) open at a predetermined pressure (typically 3bar on ch) to prevent overpressurisation of pipework.