Emerson E2 Manuel D’Utilisation

A Standard Circuit application may apply one of four 

different control methods to a case circuit: the Tempera-
ture Monitor method, the Temperature Control method, 
and the Line Up(ESR)/Defrost method, and the 
Lineup(MFESR)/Defrost method. 

The Temperature Monitor method does not control 

case temperature. The application will read and record 
case temperature inputs, but it will not make any attempt 
to control temperature. The application will still initiate 
and control defrost, cycle fans, and perform other neces-
sary functions.

A Standard Circuit application using the Temperature 

Control method will pulse the refrigeration liquid line 
solenoid OPEN and CLOSED so as to control the case 
temperature to the user-defined setpoint. The application 
monitors up to six different temperature sensors in the cir-
cuit and combines them into a single value that is com-
pared to the setpoint.

In Line Up ESR, circuit temperature is controlled by 

an electronic evaporator pressure regulator (EEPR). The 
EEPR is controlled by a PID algorithm that steps the valve 
open from 0% to 100% based on how far away the circuit 
temperature is from the setpoint.

This strategy requires the use of the Echelon-based 

ESR8 stepper regulator output board, which has been dis-
continued and replaced by the I/O Network-based Multi-
Flex ESR.

In Line Up MFESR, circuit temperature is controlled 

by an electronic evaporator pressure regulator (EEPR). 
The EEPR is controlled by a PID algorithm that steps the 
valve open from 0% to 100% based on how far away the 
circuit temperature is from the setpoint.

This new strategy requires the use of the I/O Network-

based MultiFlex ESR and should not be used with the 
Echelon-based MultiFlex ESR.

Defrost cycles in a Standard Circuit application may be 

initiated in either of three ways: by schedule (at specific 
times of the day, programmed by the user), by external 
trigger (a user-initiated signal such as a switch or button), 
or by manual command (initiated on the E2 front panel by 
the user).

The defrost cycle for a Standard Circuit application 

consists of three steps.

1.

Pump Down (Elec & Hot Gas only) - The defrost 
cycle begins with this step immediately after the 
refrigeration solenoid is turned OFF. During the 
Pump Down phase, the application waits for a 
user-specific amount of time to elapse before 
turning on the defrost heat. This allows refriger-
ant in the evaporator to be evacuated before 
defrost heat is activated. The compressor(s) 
remain ON during Pump Down.

2.

Defrost - During the defrost phase, refrigeration 
is disabled. If using electric defrost heaters will 
be ON. If using hot gas, heated refrigerant will be 
pumped through the coil. This phase will con-
tinue until the defrost is terminated (see Section 
11.3.2.3 for information on how defrost is termi-
nated).

3.

Run-Off (Elec & Hot Gas only)- After defrost 
heat is deactivated, the application waits for the 
Run-Off time to pass before re-entering refrigera-
tion mode. This allows melted frost on the evapo-
rator to drain from the coil so that it will not re-
freeze when refrigeration begins again. After the 
user-specified Run-Off time has passed, the 
defrost cycle has ended.

There are many different ways used to defrost a refrig-

erated case. A Standard Circuit application is capable of 
employing five different strategies to accommodate five 
different types of defrost.
Timed and Reverse Air

Timed defrost and Reverse Air defrost are two differ-

ent defrost strategies, but both are alike in the way they are 
controlled by a Standard Circuit application. In both 
defrost types, no heat is applied to the evaporator. The 
application simply turns the refrigeration solenoid OFF for 
the duration of the defrost cycle.

When these defrost types are used, Pump Down and 

Run-Off times are not necessary; therefore, they will not 
be part of the defrost cycle.
Hot Gas and Reversed Cycle Hot Gas

Hot Gas and Reversed Cycle Hot Gas require the use 

of hot gas from the refrigeration lines. During these types 
of defrost, the application will open the circuit’s liquid line 
solenoid AND will send a command to the refrigeration 
rack to open the Master Liquid Line Solenoid. As a result, 
heated refrigerant will be pumped through the evaporator 
coil.