Emerson Copeland EazyCool OMQ-56-Nxx-TWD Series Application Manuallines page 11

4) PT3 Pressure Transmitter (Alco Controls)
Two compressor-condensing units are equipped with HP and LP pressure transmitters
that are connected to the EC2 electronic controller.
The EC2 controller description and programming instructions are available in the
corresponding guideline (C6.1.5/E, Part no: 3136444) which is shipped with the units. It
is also available for download on www.eCopeland.com.
An Alco PT3-30A pressure transmitter is used at the high-pressure part of the system.
An Alco PT3-07A pressure controller is used at the low-pressure part of the system.
The PT3 pressure transmitter converts a pressure into a linear electrical 4-20 mA
current output signal. The heart of the transmitter is a piezo resistive chip enclosed in an
oil capsule.
Features:
Pressure sensitive piezo-based cell with strong primary output signal for precise
and sound-free operation
Vibration and pulsation resistant
2.6.7 Fan speed controller (FSP150) Alco Controls
An electronic speed control is fitted as standard in units
suitable for refrigeration networks. It controls the speed of the
fans based on condenser pressure. Fan speed is controlled by
the EC2-551 condensing unit controller in combination with a
FSP-150 fan speed controller.
Two fans are controlled at the same time.
The control operates with single-phase motors.
The electrical connection is made in the terminal box of the condensing
unit.
Using a fan speed controller offers the following benefits for your
application:
The head pressure can be kept high enough to ensure proper operation of the
expansion valve, and hence, sufficient mass flow through the expansion valve to
feed the evaporator. This maintains the required cooling capacity and avoids a
drop of evaporator temperature.
The sound level of fan motors can be kept at a minimum by avoiding the
permanent on/off cycling of the fan motor. The Alco Controls fan speed control
can be delivered with the Copeland units or as a separate accessory.
2.6.8 Liquid line equipment (only for 2 unit network configuration)
a) Filter drier Alco Controls ADK-plus
ADK-plus liquid line filter-drier is for new installation or after service.
Optimum blend of molecular sieve and activated alumina
b) Liquid sight glass Alco Controls AMI 1SS*
The AMI series of moisture indicator is designed to monitor the moisture
content within the liquid line of a refrigeration system. When the line is empty
of liquid, circles may be seen in the glass. However, when the liquid refrigerant
touches the glass, the circles disappear indicating the system is fully charged.
2.6.9 Liquid line solenoid valve (for low temp. model only) Alco
Controls 200 RBT 5
This is used in low temperature with 2, 3 & 4 unit network systems
Compact size
Snap-on clip for attaching solenoid coils
∆p minimum = 0,05 bar
C6.1.4/0305/E
Condensing Unit For Refrigeration Networks
10 Part no: 3136433