HONEYWELL RP470A (01) PDF Document

The HONEYWELL RP470A and B are three-port relays with the following differences:

HONEYWELL RP470A:

• Transmits the higher of two input signals.

• Selects the higher pressure with a sensitivity of .015 psi (1.03 kPa).

• Is used in sensor lines, such as LP914 or LP915 temperature sensors with a 1.25 to 2.50°F (0.68 to 1.3°C) accuracy, depending on sensor span.

• Has a gray body.

RP470B:

• Locks out one pressure signal when a second pressure signal is higher.

• Functions as a repeater for signal isolation.

• Functions as a lower-of-two-pressures selector.

• Has a gray and black body.

In a lower-of-two-pressures application, the RP470B requires a 0.007 Filter Restrictor (part number 14002913-002) if the input is not already restricted, such as a one-pipe device input.

The HONEYWELL RP470A can be mounted in two ways:

1. Suspended on tubing.

2. Mounted on a surface. For surface mounting, use the provided mounting clip and a NO. 10 x 1/2 in. sheet metal screw (obtain locally) to attach the relay to a wall or panel.

All connections are sharp barb for 5/32 in. (4mm) O.D. polyethylene tubing.

CAUTION: To prevent damage to the sharp barb connections, do not attempt to cut or pull the tubing. To remove tubing from barb connections, cut the tubing a few inches from the control device and use a coupling to reconnect the tubing.

To check the HONEYWELL RP470A Higher-of-Two-Pressures Relay, ensure that the higher-of-two-input pressures at Ports 3 and 5 is transmitted through output Port 2.

Testing the RP470B depends on its application:

• In a lockout relay application: Ensure that the relay passes the signal at Port 2 to Port 3 if the pressure at Port 5 is lower than the pressure at Port 2. When the pressure at Port 5 is greater than the pressure at Port 2, lockout should occur.

• In a lower-of-two-pressures application: Make sure that the output is the lower pressure.

• Models: RP470A Higher-of-Two Pressures Relay; RP470B Lockout Relay or Repeater

• Operating Pressure Range: Normal: 0 to 18 psi (0 to 124 kPa); Maximum: 30 psi (207 kPa)

• Maximum Safe Air Pressure: 30 psi (207 kPa)

• Ambient Operating Limits: Temperature: 0 to 140°F (-18 to 60°C); Relative Humidity: 5 to 95%

• Air Handling Capacity: 0.039 scfm at 1 psi (18 ml/s at 7 kPa) differential

• Construction: Molded plastic with neoprene diaphragm and valox valve seat

The HONEYWELL RP470A selects the higher of two input pressures:

• When the pressure at Port 3 is greater than the pressure at Port 5, Port 3 supplies the output through Port 2, and the output pressure at Port 2 equals the pressure at Port 3.

• When the pressure at Port 5 is greater than the pressure at Port 3, Port 3 closes off, and the output at Port 2 equals the pressure at Port 5.

The operation of the RP470B is as follows:

• When the pressure at Port 2 is greater than the input pressure at Port 5, Port 2 supplies output through Port 3.

• When the pressure at Port 5 is greater than the pressure at Port 2, the diaphragm closes off the output (Port 3). This action prevents the Port 2 signal from passing through Port 3.

Accuracy decreases when the HONEYWELL RP470A is used with circuits having 0.005 restrictors (e.g., TP974 with 0.30 psi [2.07 kPa] accuracy) compared with those having 0.007 restrictors (0.15 psi [1.03 kPa] accuracy).

The following table identifies the ports of older Honeywell pneumatic relays when upgrading your installation to a HONEYWELL RP470A.

The following table identifies the ports of older Honeywell pneumatic relays when upgrading your installation to an RP470B for lockout operation.