Emerson E2 Manuel D’Utilisation

Any user-defined Pump Down and Run-Off times will 

be observed as normal.
Electric Defrost

Electric defrost uses electric heaters to defrost the 

evaporator coil. During electric defrost, the application 
will turn the Defrost output ON to activate the heaters con-
nected to the output.

Any user-defined Pump Down and Run-Off times will 

be observed as normal.

Both the start and the end times of a defrost cycle are 

determined by the user. The Pump Down, Defrost, and 
Run-Off stages all have fixed durations, and when the last 
stage of the cycle is complete, defrost is terminated.

However, a Standard Circuit application may be pro-

grammed to terminate the Defrost stage of the defrost 
cycle early if the temperature inside the case rises above a 
fail-safe temperature setpoint (called the termination set-
point). For certain defrost types, defrost heat may also be 
“pulsed” in order to keep the temperature below the set-
point without terminating defrost.
Pulsed Defrost

Pulsed Defrost is only available if the circuit is using 

heated defrost, such as Electric or Hot Gas defrost.

Pulsed Defrost is similar to the Temperature Termina-

tion strategy outlined in Section 11.3.2.3, except a defrost 
cycle always continues for the full programmed duration.

When the termination temperature rises above the set-

point, defrost does not end. Instead, the defrost heat is 
turned OFF until the case temperature falls below the set-
point, at which time the output will come back ON to con-

tinue heating.

Figure 11-4 illustrates what happens in a pulsed 

defrost cycle. In this example, the case reaches its termina-
tion temperature approximately 2/3 of the way into its 
defrost cycle. Defrost continues, but defrost heat is turned 
OFF until the temperature falls below the setpoint, at 
which point the heat is turned back ON. 

Defrost heat will continue to be pulsed in this manner 

until the defrost time has passed. The defrost cycle will 
then begin the Run-Off period, and then restart refrigera-
tion.

When necessary, a user can initiate an emergency 

defrost cycle in a circuit. Emergency defrost cycles are 
similar to normal defrost cycles, except an emergency 
defrost cycle will ignore all calls for termination and 
remain in defrost for the entire programmed defrost time. 
For cases using a pulsed defrost strategy, this means the 
defrost heat will not be pulsed during emergency defrost.

 Emergency defrosts are initiated by the user from the 

Standard Circuit Bypass screen (see Section 12.6, Manual 
Defrost and Clean Mode). 

If an ESR8 or MultiFlex ESR is used on a circuit that 

uses hot gas defrost, values for circuits in defrost are 
forced OPEN (100%) to allow hot gas to flow through the 
evaporators. 

A Standard Circuit application may be configured to 

entirely shut down a case circuit so that it may be cleaned 
or serviced. A case circuit enters clean mode when it 
receives a signal from an input called the clean switch.

Clean switches may be set up as either “Switched” or 

“Timed.” If a clean switch is configured as “switched,” the 
circuit enters clean mode when the switch is turned ON, 
and it remains in clean mode until the switch is turned 
OFF. If a clean switch is configured as “timed,” the circuit 
enters clean mode when the switch is turned ON, and it 
remains in clean mode for a fixed user-defined amount of 
time.

During clean mode, the Fan, Defrost, and Refrigera-

tion Solenoid outputs are all turned OFF, and the liquid 
line solenoid is CLOSED.

If desired, a notice may be sent to the E2’s Alarm Log 

so that the E2 can keep track of clean modes and times.