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harry harry is offline
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Default Pressure reducing valves - do any work with zero flow?

On Saturday, 1 August 2020 12:33:04 UTC+1, Chris Green wrote:
Looking at pressure reducing valves available from Toolststion,
Screwfix and such I note that a lot of the reviews say that the
pressure builds up when there's no flow. I.e. the pressure reduction
reduces the pressure available when running a tap or (more to the
point possibly) a shower but when all taps are turned off the outlet
pressure builds up to match the inlet pressure.

I need to reduce the pressure to some small waterers (as in things for
animals to drink from) which will, if they are working, reduce the
flow to zero. Can one get pressure reduction valves for this sort of
application?

--
Chris Green
ยท


It depends on the nature of the valve seat.
Metal to metal ones are eroded by the fluid passing through and start to pass on zero flow.

Some have plastic or rubber obturating plate that remains tight for longer but usually they don't maintain as accurate a flow.

What usually happens is the safety valve (downstream of the PRV) lifts and lets the excess away. But they too suffer from the same problem of wear on the seat.