Product Overview

P66 Series Electronic Fan Speed Controls Product Bulletin2
Application
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 2). These controls
regulate 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 control 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
Operation
Condensing unit installation, operation, and
maintenance determine the overall capability to
maintain a satisfactory pressure by means of fan speed
control. Within the operating range, the P66 control
provides air delivery in direct proportion to heat
rejection requirements. This allows the refrigeration
system to perform efficiently, even in very low ambient
temperatures.
The P66 pressure transducer provides direct response
to changes in condenser pressure, regardless of the
variations in fan delivery curves. The dual input models
select the pressure input from the transducer sensing
the highest pressure.
See Figure 2 for a typical operational sequence for a
P66 control.
Repair and Replacement
Do not make field repairs. For a replacement control,
contact the Original Equipment Manufacturer or your
local Johnson Controls/PENN distributor.
IMPORTANT: Use P66 Series Electronic Fan
Speed Controls only as operating controls. Where
failure or malfunction of the P66 control could lead to
personal injury or property damage due 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 controls.
!
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.