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2.9.2
Theory of operation (2-point pressure modulation; High and Low)
The plumbing of a Sentinel installation (hydraulic control circuit only) is illustrated
below:
The Inlet port connects to the upstream side of the PRV (as long as its pressure is below
90m; see caution note), which provides pressurised water for the system to use.
With the valve in the position shown (above)
, which is the “
High
”
pressure position, the
actuator has water pressure applied. The upper chamber of the actuator fills with water,
which causes the plunger to depress the spring more. This causes the pilot valve to
open more. This decreases the pressure in the lower part of the pilot valve (the PRV
pilot rail). This leads to a decrease of pressure in the PRV upper chamber, which causes
the main valve to become more open thereby increasing the downstream pressure.
Caution:
When PRV inlet pressure exceeds 90m, an
alternative installation is required…
Use the downstream water pressure for the
Hydroswitch Pressure Feed port instead.
Hydroswitch Solenoid.
Path when at “High” (and also Default)
Pressure Feed
(Common)
