Table of Contents
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APPLICATION
R7426A,B,C Temperature Controllers use direct digital control
technology to provide more accurate and efficient operation of
heating, ventilation and air conditioning (HVAC) systems.
Parameters are preset for plug and play operation and provide
different control strategies for optimum system performance.
The controller performs proportional or proportional plus
integral (P+I) control and covers all space, supply air or water
flow applications within the specified ranges of 32°F to 130°F
or 32°F to 260°F. Standard Pt 1000 or NTC 20K ohm
temperature sensors can be used.
The modern design with its easy to operate user interface and
LCD allows complete flexibility of control system design,
accurate parameter setting, and display of actual temperature
values, setpoints and outputs.
® U.S. Registered Trademark
Copyright © 2002 Honeywell • All Rights Reserved
Temperature Controller
WITH REAL TIME CLOCK
FEATURES
• Models with selectable floating output functions:
- Floating.
- 2, 3, 4, or 6 stage.
• Models with analog outputs 0/2 to 10 Vdc selectable.
• Space/supply limit or cascade control.
• Sequence control of heating, mixed air damper,
economizer, or energy recovery system and cooling.
• Weekly time schedule with up to 6 switching points per
day.
• Automatic daylight saving time change.
• Four different operating modes: Occupied,
Unoccupied, Night, and Off.
• Yearly advance holiday programming.
• Three types of holiday schedules.
• Self-adaptive optimum start program for room control
system.
• Night-cycle program.
• Selectable control: proportional (P) or
proportional plus integral (P+I).
• Pre-programmed control parameters.
• Digital parameter setting.
• Selectable direct/reverse acting analog output.
• 24 Vac power supply.
• 3 inputs for temperature sensors.
• Automatic sensor type identification of Pt 1000
or NTC 20K ohm.
• 2 digital inputs, occupancy (alternatively summer/
winter changeover) and freeze protection.
• Start-up routine.
Application ........................................................................
Features ...........................................................................
Specifications ...................................................................
Ordering Information ........................................................
Installation ........................................................................
Introduction .......................................................................
Operation ..........................................................................
Keypad Operation ............................................................ 10
Schedules ......................................................................... 12
Troubleshooting ................................................................ 13
Appendix A ....................................................................... 14
Control and Configuration Parameters ........................ 14
Parameter Details ........................................................ 16
Appendix B ....................................................................... 20
Programming Charts ................................................... 20
R7426A,B,C
PRODUCT DATA
Contents
63-2564-1
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1
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Table of Contents
Related Manuals for Honeywell R7426B
Summary of Contents for Honeywell R7426B
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Page 1: Table Of Contents
Schedules ................. 12 Troubleshooting ..............13 Appendix A ............... 14 Control and Configuration Parameters ......14 Parameter Details ............16 Appendix B ............... 20 Programming Charts ........... 20 ® U.S. Registered Trademark Copyright © 2002 Honeywell • All Rights Reserved 63-2564-1... -
Page 2: Specifications
Honeywell, 1885 Douglas Drive North Minneapolis, Minnesota 55422-4386 In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A. -
Page 3: Installation
R7426A,B,C TEMPERATURE CONTROLLER INSTALLATION Pt 1000 sensors: C7031D1070: For hot or chilled water. C7031F1026: For outdoor air temperature. C7031J1068: For duct discharge air (averaging). When Installing this Product... C7031K1025: For hot or chilled water (strap-on). 1. Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous Table 1. - Page 4 SPRING RETURN ACTUATORS ONLY. T ERMINAL CONNECTIONS 21, 24 AND 27 CAN HONEYWELL HONEYWELL HONEYWELL BE ELIMINATED IF L1 IS WIRED DIRECTLY SERIES 61 SERIES 61 SERIES 61 TO THE ACTUATOR. ACTUATOR ACTUATOR ACTUATOR M21039A Fig. 3. R7426B typical wiring. 63-2564—1...
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Page 5: Introduction
— In either case, it can be configured for heating or cooling or auto-changeover with external input. — R7426B, with three floating outputs, can be configured to: R7426A Main Temperature Control — Stage (on/off) up to six relays in any of the following... - Page 6 Temperature Cascade Control — I01 sensor (control parameter I02ext is 1) supplies the control loop. This application will be active with the R7426B,C controllers if parameter W is set to any value other than Off. It can be Cascade Control (W...
- Page 7 R7426A,B,C TEMPERATURE CONTROLLER On the R7426C controller each output characteristic can be NOTE: See Table 3 for control logic and Fig. 9. for sequence selected via parameters DIR/REVx (where x is O1, O2 or O3). output operation. Fig. 8 shows: •...
- Page 8 NOTE: Freeze protection operation takes priority over all Parameter setting for Heating/Cooling Control Outputs: other control operations. OMode is 0, 1, 2, 3 or 4 (R7426B only); OxMode (where x is 1, 2 or 3) is 0. Table 5. Freeze Protection Actions.
- Page 9 Parameter setting for Output Switching Position: 4-STAGE ON/OFF ELECTRIC HEATING OR COOLING • OMode is 0, 1, 2, 3 or 4 (R7426B only). When OMode is 2, the output sequence of O3/O1 is controlled • OxMode (where x is 1, 2 or 3) is 1.
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Page 10: Keypad Operation
Adjustments Two Position Damper Control (R7426B,C) If parameter OMode is 4, then the R7426B,C damper output signal O1 operates as a two-position control output: Control Point / Setpoint Adjustment (CPATYP) • When the controller mode is occupied, unoccupied or The control or setpoint can be adjusted using an internal or night: O1 is 100 percent. - Page 11 WHEN POWER IS APPLIED, THE DISPLAY Limit or Cascade Sensor I02 FLASHES MODEL CODE: CP.2 Limit/Cascade Setpoint CTRP2 R7426A: Outdoor Air Compensation Sensor I03 R7426B: Output 1 R7426C: M17455 Output 2 Fig. 18. Controller Version. Output 3 Parameter Selection/Adjustment Mode...
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Page 12: Schedules
R7426A,B,C TEMPERATURE CONTROLLER SCHEDULES Table 10. Holiday Schedule Types. Special Program To Clear Type Notes Applies Program Two schedules, one for weekly switching points and one for holiday switching points, are available. These schedules and Can set off all day One specific day Automatic the clock/date are stored in the memory (EEPROM) of the at midnight... -
Page 13: Troubleshooting
R7426A,B,C TEMPERATURE CONTROLLER 11. Press SET to place this information into the EEPROM. 6. Adjust the day to the proper value. The device will cycle back to the hour. 7. Press SET to confirm this information and advance to 12. If no more changes are needed to the clock or date, set the holiday type. -
Page 14: Control And Configuration Parameters
R7426A,B,C TEMPERATURE CONTROLLER APPENDIX A Control and Configuration Parameters NOTES: Parameter Ctrltyp determines the setting: — Ctrltyp Lo selects setting I. The controller includes two groups of settings (I and II) for — Ctrltyp Hi1 and Hi2 select setting II. control and configuration parameters. - Page 15 R7426A,B,C TEMPERATURE CONTROLLER Table 14. Configuration Parameters. Parameter R7426 Setting I / Setting II Name A B C Description Default C.01 DIR/ x Selects O1 output action to adapt valve or damper direction (Dir: DA, Rev: RA). REVO1 C.02 DIR/ x Selects O3 output action to adapt valve or damper direction.
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Page 16: Parameter Details
A start-up routine is provided to prevent start-up problems for The following information applies only to controllers that have R7426B,C controllers (three outputs). Enable this routine by the noted parameter (see Tables 13 and 14). Not all setting Startup parameter to On. - Page 17 R7426A,B,C TEMPERATURE CONTROLLER Prestart Gradient: PSTG_H / PSTG_C (C.18 / C.19) For cascade control, limit setpoint W determines the control point at which: These parameters determine the necessary prestart gradients • Submaster setpoint (W ) maintains the limit value. to reach the occupied setpoint at occupancy start. The •...
- Page 18 Use the following formula for P+I control: Adjustment of parameter MINPOS is available only with ----- - R7426B,C controllers. MINPOS determines the outdoor air • Discharge air control: x ranges from 4 to 5. damper actuator minimum position. It maintains the minimum •...
- Page 19 Economizer mode when On. is available on the single output R7426A and the start R7426B when the three floating outputs are configured for NOTE: With the main temperature sensor (I01) installed in OMode = 1. the return air, set RetOffs to 0.
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Page 20: Programming Charts
Time Mode Time Mode Time Mode Time Mode Automation and Control Solutions Honeywell International Honeywell Europe S.A. Honeywell Latin American Region Honeywell Honeywell Limited-Honeywell Limitée Control Products 3 Avenue du Bourget 1985 Douglas Drive North 35 Dynamic Drive Honeywell Building...