Install Instructions

RP471A PNEUMATIC SNAP-ACTING RELAY
RP471A
POST FOR
CONNECT
1/4 IN.
(6 MM)
PLASTIC
Fig. 3. Adaptation piping.
Port Identification Table
The right column in Table 1 identifies the ports of older
Honeywell pneumatic relays when upgrading the
installation.
Table 1. Pneumatic Relay Ports.
RP471A RO49A
Pilot 3 1
Common 7 3
Normally connected 6 4
Normally disconnected 8 2
Checkout and Test
Decrease pilot pressure (port 3) to 1 psi (7 kPa) below
setpoint. This connects port 7 (Common) with port 6
(Normally Connected) and blocks port 8 (Normally
Disconnected). See Fig. 4.
Increase pilot pressure to setpoint. This connects port 7
with port 8, and blocks port 6.
6 8 6 8
7 7
PRESSURE DECREASE PRESSURE INCREASE
TO SETPOINT MINUS TO SETPOINT
DIFFERENTIAL
C8243
Fig. 4. RP471A internal port alignment.
CONNECT
1/4 IN.
(6 MM)
COPPER
5/32 IN. (4 MM) O.D.
PLASTIC TUBING
5/32 IN. (4 MM)
O.D. PLASTIC
TUBING CUT
TO LENGTH
5/32 IN. X 1/4 IN.
(4 MM X 6 MM)
O.D. PLASTIC
CONNECTOR
(CCTI606B)
1/4 IN. (6 MM)
O.D. PLASTIC
TUBING CUT TO
LENGTH
1/4 IN. (4 MM) O.D.
PLASTIC/COPPER
ADAPTER
(CCTI633BT)
1/4 IN. (6 MM) O.D.
COPPER TUBING
C8242
ENGINEERING DATA
Specifications
Model: RP471A Snap-Acting Pneumatic Relay
Operating Pressure (Switch and Pilot) Range:
Normal: 0 to 18 psi (0 to 124 kPa)
Maximum Safe: 30 psi (207 kPa)
Ambient Operating Limits:
Temperature: 0 to 140°F (-18 to 60°C)
Relative Humidity: 5 to 95%
Setpoint: 3 to 15 psi (21 to 103 kPa) (field adjustable)
Differential: Between 0.1 and 0.8 psi (0.7 and 5.5
kPa), 41 to 140°F (5 to 60°C), nonadjustable; fac-
tory set
Action: SPDT, positive snap acting
Knob Rotation: 300 degrees (from 3 to 15 psi [21 to 103
kPa] on scale)
Switching Differential: 1 psi (7 kPa), with actual
operation at 0.3 to 0.4 psi (2 to 3 kPa), nonadjustable.
Air Consumption: 0.002 scfm (1.0 l/sec)
Air Handling Capacity: 0.039 scfm at 1 psi (18 ml/s at 7
kPa) differential
Construction: Molded plastic with neoprene
diaphragms, steel spring, aluminum shaft, stainless steel
lever
Operation
The return spring has an equivalent pressure of less than
1 psi (7 kPa.). See Fig. 5. The pilot pressure at port 3
must equal or exceed the switching pressure developed
by the setpoint spring. At that point, the control chamber
port opens. Pilot pressure enters the control chamber
and pushes up the control chamber diaphragm. This
opens port 8 and closes port 6.
When pilot pressure drops below setpoint minus the
differential, the setpoint spring relaxes and closes the
control chamber port. Air trapped in the control chamber
bleeds to the atmosphere.
RP471A
VENT
SPRING
8
7
3
A
RETURN
COMMON
PILOT
VENT
CONTROL CHAMBER
PILOT CHAMBER
VENT SMALL BLEED
(40 TO 60 SCCM)
6
8
NORMALLY
CONNECTED
NORMALLY
DISCONNECTED
SPRING
SETPOINT
7
6
3
CONTROL CHAMBER PORT
C8245
Fig. 5. RP471A operation.
When control chamber pressure is less than return
spring pressure, it connects port 6 to port 7 and port 8
closes port 3 is the pilot port. See Fig. 6.
95-7252EF 2