Emerson AE4-1287 R7, Manual

6

© 2012 Emerson Climate Technologies, Inc.
Printed in the U.S.A.

AE4-1287 R7

Application Engineering

B

U

L

L

E

T

I

N

high or low resistance reading or over temperature 

condition.

The alarm relay uses a single-pole-double-throw 

contact. The contact terminals are “L”, “M”, and

“A”: 

“L” - Common (to “A” and “M”)

“L - M” - Normally Closed (compressor run. open 

   on alarm)

“L - A” - Normally Open (alarm signal, close on 

   alarm)

The Normally Closed (NC) contact of the alarm 

relay (“L” to “M”) should be wired in the compressor 

contactor control circuit so that opening this 

contact removes the compressor from the line and 

removes power to the CM. See 

Figures 5A, B, C, 

and

 D

. 

Figures 

5A 

and

  B

 also show a current sensing 

relay 

(which must be used with compressors 

employing internal over current protection. 

The current sensing relay is already included 

when using CoreSense protection)

 and Sentronic 

oil pressure switch. The control circuit is purposely 

arranged so that an internal overload protector trip 

removes power to both the Sentronic™ and the Demand 

Cooling module. This precaution prevents the oil 

pressure switch from timing out and the Demand 

Cooling solenoid from injecting when the compressor 

is not operating.

The alarm relay requires a manual reset in order to call 

attention to a system problem.

Demand Cooling

CoreSense Protection is compatible with Copeland

Demand Cooling

™

. However, the discharge temperature

protection is provided by the Demand Cooling module.

Discharge temperature information will not be 

communicated to the CoreSense Protection module. 

See 

Figure 5E

.

System Information

1. Demand Cooling is designed to work on all 

Copeland Discus

™

 compressors equipped with 

injection ports. A different kit is required for each 

compressor body style and control voltage. See 

Table 2

 for a listing of Demand Cooling Kit part 

numbers.

2. The system must be clean. A dirty system may 

have foreign material that can lodge in the solenoid 

ori

fi

 ce. Always install a liquid line 

fi

 lter dryer in 

the injection valve inlet line capable of removing 

particles as small as 25 microns.

3. Do not use any 

fi

 lters containing materials that 

can leave the 

fi

 lter and possibly clog the IV ori

fi

 ce.

4. The liquid refrigerant supply line must be a 

minimum of 3/8" and routed so it will not interfere 

with compressor maintenance. Liquid refrigerant 

must have suf

fi

 cient subcooling at the injection 

valve to prevent 

fl

 ashing upstream of the valve.

5.  The liquid refrigerant supply line to the IV must be 

supported so that it does not place stress on the 

IV and IV tubing or permit excess vibration. Failure 

to make this provision may result in damage to the 

IV and its tubing and/or refrigerant loss.

6.  A head fan must be used to help lower compressor 

discharge temperatures for compressors using 

HCFC-22. Contact your Application Engineer for 

head fan requirements with other refrigerants.

7.  Return gas temperatures must 

NOT

 exceed 65°F.

8. System designers are advised to review their 

defrost schemes to avoid floodback to the 

compressor which may occur at defrost termination 

with HCFC-22, HFC-407A, HFC-407C and HFC-

407F. These refrigerants have a signi

fi

 cantly 

higher heat of vaporization than does CFC-502, 

and if the same design parameters used with CFC-

502 are used, 

fl

 oodback may occur.

Demand Cooling with Discus Compressor Unloading

Demand Cooling has been approved with unloading 

for 4D, 6D and 3D Copeland Discus Digital™. Demand 

Cooling has NOT been approved for 3D Moduload. 

Note! For Discus compressors with CoreSense 

Diagnostics with the build of material (BOM) 

nomenclature beginning with -ADx (e.g. 4DKNF63KL-

TSK-AD0) Demand Cooling capability is built in. 

4D and 6D Unloading with Demand Cooling

Demand Cooling protection is applicable with 

compressors using conventional blocked suction 

unloading. Earlier application guidelines required 

that liquid injection only occur when the compressor 

is in its fully loaded state. This was to avoid 

fl

 ooding 

the compressor with saturated liquid. After further 

evaluation, Emerson engineering has determined 

that the Copeland Discus compressor will still 

fl

 ash 

the injected liquid refrigerant when the compressor is 

unloaded should the discharge temperatures govern 

the need for added cooling. The Demand Cooling