PRODUCT DATA
63-2564-1
® U.S. Registered Trademark
Copyright © 2002 Honeywell • All Rights Reserved
R7426A,B,C
Temperature Controller
WITH REAL TIME CLOCK
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.
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.
Contents
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