Tjernlund CPC-2 Constant Pressure Controller (Discontinued) 8504091 Rev A 03/01 - Manual (Page 4)

TABLE OF CONTENTS
Page(s)
Description and Operation...............................................................................................................................................1
Specifications ..................................................................................................................................................................1
Cautions ..........................................................................................................................................................................2
Installation of CPC-2, Transducer & Balancing Dampers ...............................................................................................2
CPC-2 Circuit Board Features & Circuit Board Layout ................................................................................................2-4
Modes of Operation and Programming CPC-2 Controller ...........................................................................................5-7
Initial System Power Up and Setup of CPC-2 .............................................................................................................7-9
CPC-2 Fault Messages ..............................................................................................................................................9-10
Wiring........................................................................................................................................................................10-13
Replacement Parts & Warranty .....................................................................................................................................14
Tjernlund Products welcomes your comments and questions. Call us at 800-255-4208, Fax 651-426-9547, Email us at
[email protected] or write to: Customer Service, Tjernlund Products, Inc., 1601 Ninth Street, White Bear Lake, MN 55110-6794.
DESCRIPTION AND OPERATION
The CPC-2 controls the motor speed of Tjernlund variable speed Auto-Draft® Venters, Draft Inducers, Power Venters and Combustion
Air In-Forcers. It requires a Pressure Transducer and a Tjernlund Variable Frequency Drive (VFD) to automatically modulate motor
speed. The installer/user may select a pressure set point via the key pad on the CPC-2. The transducer outputs a signal to the CPC-2
proportional to the pressure or draft that it senses. The CPC-2 outputs a proportional signal to the VFD, which modulates the frequen-
cy of the voltage to the motor, causing it to speed up or slow down so that the pressure or draft set point is maintained.
Integral to the CPC-2 are two heating appliance interlock circuits. When an appliance calls for heat the burner control signal is inter-
cepted, causing the Auto-Draft® Venter, Draft Inducer, Power Venter or Combustion Air In-Forcer to speed up until the pressure set
point is reached. If the set point is not reached within CPC-2 allowable limits (See Modes of Operation), the interlocked appliance(s)
will not fire.
When a pre-purge time is selected the controller will not allow the appliance(s) to operate until the pressure set point is reached and
the pre-purge time has elapsed. When a post-purge time is selected the appliances are deactivated as soon as the call for heat is
satisfied, but the Auto-Draft® Venter, Draft Inducer, Power Venter or Combustion Air In-Forcer will continue to maintain the pressure
set point until the post-purge time has elapsed. The secondary Fan Prover Switch model PSA-1 is adjusted by the installer to the vent
system draft set point and wires into a terminal strip on the CPC-2. The Transducer in conjunction with the CPC-2 Controller is
considered the primary draft proving control.
The CPC-2 can also be operated in the Manual mode, regulating the motor at a constant, user set speed. The Venter Only mode
allows the user to regulate the motor at a constant, user set speed, but will not allow any interlocked heating appliances to operate.
COMPLETE AUTO-DRAFT® VENT SYSTEM SOLUTIONS
This installation manual does not contain any system design documentation. Installation and use of Auto-Draft® Venters or EXP-4
Appliance Interlock Expansion boards are not covered by this manual. Please refer to those accessory installation manuals.
SPECIFICATIONS
1