User Guide

Installation Instructions
Issue Date September 30, 2009
© 2009 Johnson Controls, Inc. 1
P66 Series Electronic Fan Speed Controls
Application
IMPORTANT: Use this P66 Series Electronic Fan
Speed Control only as an operating control. Where
failure or malfunction of the P66 control could lead to
personal injury or property damage to the controlled
equipment or other property, additional precautions
must be designed into the control system.
Incorporate and maintain other devices, such as
supervisory or alarm systems or safety or limit
controls, intended to warn of or protect against
failure or malfunction of the P66 control.
Part No. 24-7664-1482, Rev. D
The P66 Series Electronic Fan Speed Controls are
pressure-actuated electronic motor-speed controllers
designed primarily to control condenser fan motors on
Heating, Ventilating, Air Conditioning, and
Refrigeration (HVAC/R) applications (Figure 1). These
controls vary the supply voltage to the fan motor in
response to the sensed refrigerant pressure, providing
direct response to changes in condenser pressure,
regardless of the variations in air delivery curves.
P66 controls are available with one or two pressure
sensor inputs. In dual sensor models, the control
selects the input with the greatest demand.
P66 control models are also available with NEMA 3R
(Rainproof) enclosures for outdoor applications
(Figure 1). These models come with a plastic
enclosure, appropriate gaskets, and low voltage wire
leads for 24 VAC power. In addition, the critical high
voltage components are encapsulated in a potting
compound.
Note: NEMA 1 models cannot be retrofitted in the
field to obtain the NEMA 3R (Rainproof) rating.
A P66 and speed controlled motor can replace On/Off
fan cycling controls, multiple speed motors, condenser
flood-back systems, temperature fan-speed controls,
and modulating louver systems.
Typical applications include:
• computer room air conditioning
• commercial air conditioning
• commercial refrigeration
The P66 Series controls must be applied only to
single-phase motors intended for use with a solid-state
motor speed control. An applicable motor must be a
single-phase, permanent split-capacitor motor and
must be:
• ball-bearing construction only (Sleeve-bearing
motors are not acceptable for use with P66
controls.)
• designed to handle non-sinusoidal waveforms
generated by solid-state motor speed controls
• designed to dissipate the motor heat generated at
reduced speed operation
!
CAUTION: Risk of Property Damage
Use only single-phase Permanent Split-Capacitor
(PSC) motors approved by the manufacturer for
speed control applications with the P66 control.
Failure to use a single-phase PSC motor may
damage the motor and other property.
Installation
!
WARNING: Risk of Personal Injury
Do not install the P66 Electronic Fan Speed Control
in any application using corrosive or flammable
refrigerants. The P66 control is not designed or
intended for use with those refrigerants. Use of the
P66 control with corrosive or flammable refrigerants
may lead to release of refrigerant, which could cause
property damage, fire, severe personal injury or
death.