Emerson E2 Manuel D’Utilisation

time, Superheat Control will begin.

Recovery Mode always lasts for a specific number of 

seconds. The case controller determines the duration based 
on past performance of the evaporator during previous 
Recovery Modes.
Thermostatic Expansion Valves (TXVs)

As an alternative to regulating superheat using EEVs, 

case controllers also support cases that use mechanical 
thermostatic expansion valves (TXVs). When TXVs are 
being used, the case controllers use only Temperature 
Control to turn refrigeration ON and OFF. Superheat 
Control is disabled, since it is assumed the TXV is tak-
ing care of the superheat.

The CC-100H, CS-100, and CCB (suction stepper and 

lineup) control case temperature from the suction side of 
the evaporator by using an EEPR to regulate suction pres-
sure. 

Suction-side control differs from liquid-side control in 

that Superheat Control is not used. In liquid-side control, 
the valve aperture is controlled in order to achieve a super-
heat setpoint. In suction-side control, the CC-100 changes 
the valve aperture to achieve the case temperature set-
point.

Case temperature may be supplied by a supply air sen-

sor, return air sensor, or a mixture of the two values.

Temperature Control uses PID control to operate the 

valve and keep the case temperature input value equal to 
the case temperature setpoint.
Recovery Mode

Recovery Mode for suction-side case controllers is 

slightly different than Recovery Mode for liquid-side 
controllers. Suction-side case controllers enter Recovery 
Mode only after a defrost or cleaning cycle, and it does 
so in order to bring the case temperature down to a level 
that is controllable by Temperature Control.

During Recovery Mode, the valve is opened to a fixed 

percentage until the case temperature falls below the 
case setpoint. When this occurs, the case controller exits 
Recovery Mode and begins normal Temperature Con-
trol.

The physical aspects of defrost control, such as shut-

ting off valves and turning on defrost heat sources, is han-
dled by the case controller. When operating on its own, a 
case controller initiates defrost cycles at programmed time 
intervals. When connected to a Case Circuit application, 
the case controllers’ defrost times are coordinated and 
scheduled by the E2.

The defrost cycle for a Case Circuit application con-

sists of three steps. Of these three, steps #1 and #3 apply 
only to cases with heated defrosts:

1.

Pump Down - 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 refrigerant in the evaporator to be 
evacuated before defrost heat is activated. The 
compressor(s) remain ON during Pump Down. 

         Pump Down times may only be used for hot gas       

and electric type defrosts.

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 - After defrost heat is deactivated, the 
application waits for the Run-Off time to pass 
before re-entering refrigeration mode. This 
allows melted frost on the evaporator to drain 
from the coil so that it will not re-freeze when 
refrigeration begins again. After the user-speci-
fied Run-Off time has passed, the defrost cycle 
has ended.

Run-Off times may only be programmed for hot 
gas and electric type defrosts.

There are many different ways used to defrost a refrig-

erated case. A case controller is capable of using three dif-
ferent types of defrost. 
Off Cycle (Timed)

Off Cycle defrost (also known as Timed defrost) is 

simply a period of time during which refrigeration is sus-
pended. No heat is applied to the evaporator. The applica-
tion simply turns refrigerant flow 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 valve and pump 
heated refrigerant through the evaporator coil. Any user-