Brochure

The performance specifications are nominal and conform to acceptable industry standards. For applications at conditions beyond these specifications, consult the local Johnson Controls office.
Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products. © 2015 Johnson Controls, Inc. www.johnsoncontrols.com
R-182
V248 Series Three-Way Pressure-Actuated Water-Regulating Valves for
High-Pressure Refrigerants (Continued)
Valves and Valve Accessories
3. Determine the available water pressure to the valve (P
AVAIL
) using
the following steps. This the actual water pressure available to force
water through the valve.
a. Determine the minimum inlet pressure (P
IN
). This is the water
pressure from city water mains, pumps, or other sources.
b. Pressure drop through condenser (
P
COND
) is the difference in
water pressure between the condenser inlet and the condenser
outlet. Obtain this information from the condenser manufacturer.
c. Estimate or calculate the pressure drop through all associated
piping (P
LOSS
).
d. Subtract the
P
COND
and P
LOSS
from P
IN
. The result is P
AVAIL
.
4. Select the proper valve size from the flowcharts by locating a point
on a chart that satisfies the flow, the head pressure rise above
opening point, and the pressure drop across the valve.
Metric Conversions
Use these equations to convert between U.S. and S.I. units.
•1 dm
3
/s = 3.6 m
3
/h = 15.9 U.S. gal. /min. = 13.2 U.K. gal. /min.
• 1 bar = 100 kPa = 0.1 MPa  1.02 kg/cm
2
= 0.987 atm  14.5 psig
Refrigerant Head Pressure Rise
FIG
:eqn_hd_prssr_rs
P = P - P
RISE COND OPEN
Available Water Pressure
Cooling Tower
Pump
P
1
P
2
P
P
Loss 1
Loss 2
3-Way
Valve
P
IN
COND
P
P
1
P
2
=
-
LOSS
P
P
P
Loss 1
Loss 2
=
+
+ ...
Condenser
Balancing Valve
Bypass Line
FIG:3wy_prss_dr
p
P= P- (P + P)
AVAIL IN COND LOSS

Applications
Each application is unique and requires specific engineering data to
properly size and design a system to fulfill the appropriate
requirements. Typically, a valve is replaced with another valve of the
same size in a properly sized and engineered system. In North
America, contact Johnson Controls/PENN® Refrigeration Application
Engineering at 1-800-275-5676 to obtain specific engineering data. In
other areas, contact the local Johnson Controls® sales office to obtain
specific engineering data.
To make a rough field estimate of the size of valve for an application,
find the valve size needed by locating a point on a flow chart that
satisfies these requirements:
• water flow required by the condenser (Flow)
• refrigerant head pressure rise (P
RISE
)
• available water pressure (P
AVAIL
)
Follow these steps, and use the information obtained to locate a point
on one of the flowcharts that satisfies all three steps.
1. Take the water flow required by the condenser (Flow) from
information provided by the manufacturer of the condensing unit. If
the manufacturer’s information is unavailable, use the following
information to make a rough approximation of water flow in gallons
per minute (gpm) [cubic meters per hour (m
3
/hr)]:
• System Capacity (Tons of Refrigeration)
• Outlet Water Temperature (Temp.
Outlet
)
• Inlet Water Temperature (Temp.
Inlet
)
Calculate the flow using the following formula:
Note: If the outlet temperature is unknown, assume it to be 10F
(6C) above the inlet temperature.
2. Determine refrigerant head pressure rise above the valve opening
point (P
RISE
) using the following steps:
a. The Valve Closing Pressure (P
CLOSE
) is equal to the
refrigerant pressure at the highest ambient temperature the
refrigeration equipment experiences in the Off cycle. Use a
Pressure-Temperature Chart for the refrigerant selected to find
this pressure.
b. To approximate the Valve Opening Pressure (P
OPEN
), add
about 10 psig (0.7 bar) to the Valve Closing Pressure.
c. From the Pressure-Temperature Chart for the refrigerant
selected, read the Refrigerant Condensing Pressure (P
COND
)
(operating head pressure) corresponding to the selected
condensing temperature.
d. Subtract the Valve Opening Pressure from the Refrigerant
Condensing Pressure. This gives the head pressure rise.
Flow Required
Flow =
Tons of Refrigeration x 30
(Temp. - Temp. )
Outlet Inlet
FIG:flw_eqn
Valve Opening Pressure
FIG:eqn_
opn_prssr
P = P +10 psi (0.7 bar)
OPEN CLOSE