Product Overview

P266 Series Single-Phase Condenser Fan Speed Control Product Bulletin2
Application
The P266 Series Single-Phase Condenser Fan Speed
Control, in conjunction with a P266 Series Electronic
Pressure Transducer, is a pressure-actuated, digital
electronic motor speed control designed for approved
single-phase, PSC motors used in a wide variety of
Heating, Ventilation, Air Conditioning, and Refrigeration
(HVACR) applications.
The P266 Series Fan Speed Control regulates supply
voltage to the fan motor in response to the condenser
refrigerant pressure and maintains the appropriate fan
speed (air movement) through the condenser
regardless of the ambient temperature or air delivery
variations.
The P266 Series control is housed in a NEMA 3R
(IP54) rainproof enclosure for outdoor applications.
The P266 Series control is an energy efficient and
effective alternative to On/Off fan-cycling controls,
multiple-speed motors, temperature fan-speed
controls, modulating air-damper systems, condenser
flood-back systems, and other condenser pressure
control methods.
P266 Series Fan Speed Control applications include:
• computer room air conditioning
• commercial refrigeration
• commercial air conditioning
P266 Series Fan Speed Control Operation
The P266 Series control regulates fan motor speed by
limiting the supply voltage to the motor based on the
sensed condenser pressure. In a typical P266 Series
control application, as the condenser pressure rises,
the P266 Series control increases the supply voltage to
the fan motor, which increases fan speed and air
movement across the condenser coil. The increased
air movement removes condenser heat faster, which
maintains the condenser pressure within the defined
range.
P266 Series Setup Values and Modes
The P266 Series control ships with up to ten factory
default setup values and modes. These settings can be
adjusted in the field (if required) to meet your specific
condenser application requirements.
The P266 Series control’s adjustable settings include:
• Start Voltage establishes the initial minimum
voltage delivered by the P266 Series control to the
fan motor to idle the fan motor at the minimum
speed.
• Start Pressure establishes the pressure setpoint
(psi or bar) at which the P266 Series control
outputs the Start Voltage and runs the fan motor at
minimum speed.
• End Voltage establishes the voltage output that is
maintained by the P266 Series control when the
sensed pressure is equal to or greater than the
End Pressure. The End Voltage to the motor can
be set to either 95% or 97% of the total input
voltage to the P266 Series control.
• End Pressure establishes the pressure setpoint
(bar or psi) at which the P266 Series control
outputs the End Voltage and runs the fan motor at
maximum speed.
Figure 2 show the relationship between Start Voltage,
Start Pressure, End Voltage, and End Pressure.
Low Pressure Mode (LPM) determines whether the
fan motor is powered On (at the start voltage and
typically idling at minimum speed) or is Off when the
condenser pressure is below Start Pressure. See
Figure 2.
IMPORTANT: Use this P266 Series Single-Phase
Condenser Fan Speed Control only as an operating
control. Where failure or malfunction of the P266
Series Fan Speed 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 P266 Series Fan Speed
Control.
!
CAUTION: Risk of Property Damage
Use only single-phase Permanent Split
Capacitor (PSC) motors approved by the
manufacturer for speed control
applications with the P266 Series control.
Failure to use a single-phase PSC motor
may damage the motor and other
property.