Specifications; Operation; Rp920A Or C Controller; Rp920B Or D Controller - Honeywell RP920A-D Service Data

SPECIFICATIONS

Models:
RP920A: Single-Input Controller
RP920B: Dual-Input Controller
RP920C: Single-Input P + I Controller
RP920D: Dual-Input P + I Controller
Main Air Supply:
18 psi (124 kPa)
Minimum Air Pressure:
15 psi (103 kPa) minimum
Maximum Safe Air Pressure:
30 psi (207 kPa)
Input Signal:
3 to 15 psi (21 to 103 kPa)
Output Signal:
3 to 13 psi (21 to 90 kPa)
Air Consumption:
and C: 0.021 scfm (9.9 ml/s)
RP920B and D: 0.046 scfm (21.7 ml/s)
Sensor: 0.019 scfm (9.0 ml/s) depending on
sensor selected
Air Capacity:
0.07 scfm (33.0 ml/s) at 18 psi (124kPa) with 1 psi (7 kPa)
pressure difference
Proportional Band:
2.5 to 50%, field adjustable
Authority (RP920B and D Only):
5 to 300% of primary sensor span
Compensation Start Point (RP920B and D Only):
0 to 100% of compensation sensor span
Integral Reset Time (RP920C and D Only):
0.5 to 20 minutes, field adjustable
Ambient Temperature:
40 to 130F (5 to 55C)
85-0142

OPERATION

RP920A OR C CONTROLLER

In the mixed air control system with high limit (Fig. 1),
the primary controller modulates the outdoor and return air
damper to maintain the mixed air temperature set on the
controller. As the outdoor temperature rises through the
narrow throttling range of the limit controller, the dampers
are gradually returned to the minimum position as set on the
minimum position switch. When the fan is off, the dampers
assume the normal positions.
In the hot water converter control system (Fig. l), the
primary sensor in the hot water supply from the converter
modulates the steam valve on the steam supply to the
converter to maintain the hot water temperature. As the
water temperature rises through the throttling range the
valve moves from open to closed. If the CPA is used, it can
change the control point temperature
sensor span.

RP920B OR D CONTROLLER

In the dual-input control system (Fig. 2), the setpoint of
the primary sensor, located in the discharge air, is reset by
the compensation sensor in the outdoor air. Adjustments are
made on the controller to change the discharge air tempera­
ture according to a predetermined compensation reset
schedule (Fig. 3). The RP920D provides finer control in this
application because of the integral action.

MAINTENANCE

EQUIPMENT REQUIRED

1. Gage 305965 (0- to 30-psi).
2. Gage Adaptor 729 with plug-in fittings.
3. Receiver Gage to match primary sensor (see Pneu­
matic Indication, Receiver, and Target Gages Specifi­
cation Data 77-6091).
4. Barb Fitting 14003755-001 (integral models).
5. Controller Calibration Kit MQP8 16A,
6. Pneumatic Calibration Kit
percent x the