45
Table 5 — Piping Components (cont)
LEGEND
*Check all system component pressure ratings (coils, values,
pumps, etc.) with manufacturer and any applicable local or national
piping codes prior to specifying system pressure rating.
SYMBOL/SKETCH
DESCRIPTION
C
V
FACTOR
RATING*
STEAM
USE
1
/
2
3
/
4
PSI
F
MODULATING VALVE (Optional)
(Non-Spring Return, Proportional Type Actuator):
Modulating valves are designed to control the flow in
the circuit by making incremental adjustments to the
flow path within the valve.
Application — To control fluid flow in fan coil units.
On the commercial fan coil models, the factory pro-
vided modulating valve has application restrictions.
In these models, the valve packages are located in
the airstream, downstream of the coil. Due to the
ambient temperature limitations of the modulating
valves, the valves can only be used in the units listed
above with 2-pipe cooling only systems.
4.0
300
200
N/A
MODULATING VALVE (Requires ETO)
(Spring Return): Modulating valves are designed to
control the flow in the circuit by making incremental
adjustments to the flow path within the valve.
Application — Same comments as non-spring return
except when powered, the actuator moves to the
desired position, at the same time tensing the spring
return system. When power is removed for more
than two minutes the spring returns the actuator to
the normal position.
4.0
300
200
N/A
AQUASTAT: Water temperature sensing electrical
switch. (Line Voltage Controls)
Application — Clips directly on nominal size
1
/
2
in. or
3
/
4
in. copper tubing for water temperature sensing.
Must be correctly located for proper control opera-
tion.
CHANGEOVER SENSOR: Water temperature sen-
sor thermistor.
Application — Sensor shall clamp on the outside
diameter of the pipe. Sensor plate shall bend to allow
its radius to be adjusted to fit the pipe. Sensor shall
be secured to the pipe with mounting clamp. Insulate
the mounting location of sensor on the pipe.
C
v
— Coefficient of Velocity
DX
— Direct Expansion
ETO — Engineering to Order
