The RP908A and B are force balance pneumatic
amplifiers, with adjustable proportional band, for use as
Controllers in HVAC systems,
The RP908 is no longer being manufactured. There is
an RP920 model available for all RP908A and B applica-
tions. Refer to Application Replacement Listing in the
The RP908A, in conjunction with a remote sensor,
provides direct or limit control in air conditioning con-
trol systems, with or without remote control point
adjustment (CPA). It may be adjusted for either direct or
reverse acting operation. Refer to Figures 1 and 2 for
Fig. 1. Typical RP908A Primary Control of Normally
RP908A & B
Fig. 2. Typical RP908A Low Limit Control.
The RP908B dual input Controller is applied to com-
pensating systems by using an additional compensating
signal to change the control point of the Controller (Fig.
3). Temperature, humidity, pressure, or dewpoint may
be controlled by using the appropriate sensors,
MLFTAB: 111 C. 6.