Emerson EC2-391 Operating Instructions

Note: This document contains short form instructions for experienced users.
Use last column in List of Parameters to document your individual settings.
More detailed information can be found in the User Manual.
The EC2-391 is a dedicated refrigeration controller with superheat and a driver for
an Alco Controls Electric Control Valve EX2. In addition the EC2-391 controls air
temperature and manages defrost and fan(s).
Two ECN-Pxx pipe temperature sensors (1) and (2) measure suction gas
temperatures at the evaporator inlet / outlet and feed the signals into the superheat
control loop. The superheat controller output modulates the opening of the EX2
pulse width modulated Electrical Control Valve (6) thus optimising the refrigerant
mass flow through the evaporator. The air temperature sensors (3) and (4) measure
air-in and out temperature of the evaporator and feed signals into the air
temperature thermostat. The ECN-Fxx fin sensor (5) is used for defrost
termination. The controller has 3 relay outputs to control the defrost heater (9), the
evaporator fan (8) and an optional output (7). Please consult the technical data
(right) for input and output ratings.
In case of power loss, due to the positive shut-off characteristics of the EX2
Electrical Control Valves, a liquid line solenoid valve is not needed to prevent
flooding of the compressor.
!
Safety instructions:
Read installation instructions thoroughly. Failure to comply can result in
•
device failure, system damage or personal injury.
The product is intended for use by persons having the appropriate
•
knowledge and skills.
Ensure electrical ratings per technical data are not exceeded.
•
Disconnect all voltages from system before installation.
•
Keep temperatures within nominal limits.
•
Comply with local electrical regulations when wiring
•
EC2-391_65136_EN_R01.doc
EC2-391 Display Case and Coldroom Controller
Operating Instructions
Replacement for 00
Technical Data
EC2 Series Controller
Power supply 24VAC ±10%; 50/60Hz; Class II
Power consumption 20VA max including EX2
Communication LonWorks® Interface, FTT10, RJ45 connector
Plug-in connector size Removable screw terminals
wire size 0.14 ... 1.5mm
Temperature
storage -20 ... +65°C
operating
Humidity 0...80% r.h. non condensing
Protection class IP65 (front protection with gasket)
Pressure transmitter input 24VDC, 4...20mA
Output relays (3) SPDT contacts, AgCdO
Inductive (AC15) 250V/2A
Resistive (AC1) 250V/8A; 12A total return current
Triac output for EX2 24V AC, 0.1 ... 1A
Electrical Control Valve
Coil (ASC 24V only)
Marking
Mounting
The EC2-391 can be mounted in panels with a 71 x
29 mm cutout. See dimensional drawing below for
space requirements including rear connectors.
Push controller into panel cutout.(1)
Make sure that mounting lugs are flush with outside
of controller housing
Insert allen key into front panel holes and turn
clockwise. Mounting lugs will turn and gradually
move towards panel (2)
Turn allen key until mounting lug barely touches
panel. Then move other mounting lug to the same
position (3)
Tighten both sides very carefully until controller is
secured. Do not over tighten as mounting lugs will
break easily.

Electrical Installation

Refer to the electrical wiring diagram (below) for electrical connections. A copy of
this diagram is labeled on the controller. Use connection wires/cables suitable for
90°C operation (EN 60730-1).
EC2 analog inputs are for dedicated sensors only and should not be connected to
any other devices. Important: Keep controller and sensor wiring well separated
from mains wiring. Minimum recommended distance 30mm.
Warning: Use a class II category transformer for 24VAC power supply
(EN 60742). Do not ground the 24VAC lines. We recommend to use one
transformer per EC2 controller and to use separate transformers for 3
controllers, to avoid possible interference or grounding problems in the power
supply. Connecting any EC2 inputs to mains voltage will permanently damage the
EC2.
1 / 4
2
0 ... +60°C
PCN: 865 022
GB
rd
party
21.09.2007