User Guide

V46
Issue 9911
Catalogue Section 7
© 1999 Johnson Controls Inc.
Order No. PD-V46-E
2
N
ote
All series V46 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, a separate pressure relief or
safety shut off valve, as applicable, must
be added by the user.
D
escription
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. Only five metal
parts, made of corrosion resistant material,
come in contact with the water. These are the
valve disc holder, the disc stud, the valve seat,
the valve stem, and the body.
A
djustments
The pressure at which the valve starts to open
(= opening point) 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.)
M
anual 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.
V
alve 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
3
/h).
- The maximum allowed pressure drop (=
∆
P)
across the valve (in bar).
- The head pressure rise (= HPR) which is the
difference between the pressure where the
valve starts to open and the condenser
operating pressure.
N
ote
At a certain pressure the valve starts to
open. If the pressure decreases, the valve
will close again at a
≈
0,5 bar lower
pressure than the pressure where the valve
starts to open.
N
ote
If the compressor operates in a high
ambient temperature, the refrigerant
pressure may at times remain high enough
to cause the valve to partly open when the
compressor is idle. In such conditions the
valve opening point should be raised just
enough to cause the valve to close during
compressor standby periods. Take this into
account when the head pressure rise
(HPR) is calculated.
The valve size can be selected by the use of:
- the diagram (see page 3 and 4).
- K
v
factors and calculation formulae (see
page 3). This can only be used when the
allowed head pressure rise is 3 bar or higher.
At lower head pressure rises the diagram
has to be used.