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2
Note
All series V48 water regulating valves are
designed for use only as operating devices.
Where system closure, improper flow or
loss of pressure due to valve failure can
result in personal injury and/or loss of
property, the user must add a separate
safety device.
Description
A pressure-balanced design employing rubber
sealing diaphragms correctly proportioned to the
valve port area, balances valve against both
gradual and sudden water pressure changes,
and seals water away from range spring,
guides, and sliding parts so these are not
submerged in water where they would be
subject to sedimentation and corrosion.
Adjustment
The pressure at which the valve starts to open
(= opening point port 1 to port 2) can be
adjusted by the adjusting screw located at the
top of the range spring housing. Valves may be
adjusted with standard service valve wrenches
or screwdrivers. (Valves are not factory set at a
certain value.)
Manual flushing
Valves may be manually flushed by lifting the
lower spring guide with screwdrivers at two
sides of the pressure plate to open valve. This
does not affect valve adjustment.
Installation
At a certain (adjustable) pressure, port 1 to port
2 starts to open, while port 1 to port 3 starts to
close. This so called "opening point" is
adjustable with the screw on the top of the
spring housing and results in an equal amount
change in both condenser and by-pass settings.
Valve size selection
The valve size is determined by three data:
- The required maximum flow (quantity of liquid
= Q) that must pass the valve (in m
- The maximum allowed pressure drop (= ∆P)
across the valve (in bar).
- The head pressure rise (= HPR) which is the
difference between the pressure where port 1
to port 2 starts to open and the condenser
operating pressure.
Catalogue Section 7
Note
At a certain pressure port 1 to port 2 starts
to open. If the pressure decreases, it will
close again at a ≈ 0,5 bar lower pressure
than the pressure where it starts to open.
The valve size can be selected by the use of:
-
-
Cut-away section V48
/h).
3
the diagrams on pages 4 and 5.
k v factors and calculation formulae (see page
3). This can only be used when the allowed
≥
head pressure rise is
≥
range valves and
3 bar for 4/16, 4/20 and
6/20 bar range valves. At lower head
pressure rises the diagram has to be used.
1
3
1 From cooling system
2 To condenser
3 By-pass
Fig. 1
© 2002 Johnson Controls Inc.
V48
Issue 09/01/2003
2 bar for 1.5/7.5 bar
2
Code No. PD-V48-E
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