Bard MC4000 installation instructions Manual, Page, 10 of

4th cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 3. On a call for 4th Stage cooling the Stage 4 LED comes on solid (no delay), and the lag unit compressor will switch to compressor Stage 2 full capacity operation.

3.1-Stage Compressor Units with Older EIFM Economizers (Enthalpy OD Sensor)

1st stage cooling set point is the setting (SP) input into the controller. Factory default is 77F (25C). On a call for cooling the blower of the lead unit will come on immediately (if not already on – See Blower Operation), and the Stage 1 LED will blink for 10-seconds before going solid, at which time the lead unit Y1 cooling output turns on. If the outdoor temperature and humidity conditions are below the set point of the economizer control the lead unit economizer will operate instead of the compressor. If outdoor conditions are not acceptable for free cooling the compressor will automatically operate instead of the economizer.

2nd cooling set point is 4F (default setting, user selectable 2-6F) warmer than Stage 1. On a call for 2nd Stage cooling the blower of the lag unit is turned on (if not already on – See Blower Operation), and the Stage 2 LED will blink for 10-seconds before going solid, at which time the lag unit Y1 cooling output turns on. If the outdoor temperature and humidity conditions are below the set point of the economizer control the lag unit economizer will operate instead of the compressor. If outdoor conditions are not acceptable for free cooling the compressor will automatically operate instead of the economizer.

3rd cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 2. On a call for 3rd Stage cooling the lead unit economizer will close and the compressor will operate.

4th cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 3. On a call for 4th Stage cooling the lag unit economizer will close and the compressor will operate.

4.1-Stage Compressor Units with Newer ECONWMT Economizers (See Note A)

1st stage cooling set point is the setting (SP) input into the controller. Factory default is 77F (25C). On a call for cooling the blower of the lead unit will come on immediately (if not already on – See Blower Operation), and the Stage 1 LED will blink for 10-seconds before going solid, at which time the lead unit Y1 cooling output turns on. If the outdoor temperature and humidity conditions are below the set point of the economizer control the lead unit economizer will operate instead of the compressor. If outdoor conditions are not acceptable for free cooling the compressor will automatically operate instead of the economizer.

2nd cooling set point is 4F (default setting, user selectable 2- 6F) warmer than Stage 1. On a call for 2nd Stage cooling the blower of the lag unit is turned on (if not already on – See Blower Operation), and the Stage 2 LED will blink for 10- seconds before going solid, at which time the lag unit Y1 cooling output turns on. If the outdoor temperature and humidity conditions are below the set point of the economizer control the lag unit economizer will operate instead of the compressor. If outdoor conditions are not acceptable for free cooling the compressor will automatically operate instead of the economizer.

3rd cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 2. On a call for 3rd Stage cooling the lead unit economizer will continue to operate as long as outdoor conditions are acceptable, and the compressor will operate.

4th cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 3. On a call for 4th Stage cooling the lag unit economizer will continue to operate as long as outdoor conditions are acceptable, and the compressor will operate.

5.2-Stage Compressor Units with Older EIFM Economizers

1st stage cooling set point is the setting (SP) input into the controller. Factory default is 77F (25C). On a call for cooling the blower of the lead unit will come on immediately (if not already on – See Blower Operation), and the Stage 1 LED will blink for 10-seconds before going solid, at which time the lead unit Y1 cooling output turns on. If the outdoor temperature and humidity conditions are below the set point of the economizer control the lead unit economizer will operate instead of the compressor. If outdoor conditions are not acceptable for free cooling the compressor will automatically operate on compressor Stage 1 partial capacity instead of the economizer.

2nd cooling set point is 4F (default setting, user selectable 2-6F) warmer than Stage 1. On a call for 2nd Stage cooling the blower of the lag unit is turned on (if not already on – See Blower Operation), and the Stage 2 LED will blink for 10-seconds before going solid, at which time the lag unit Y1 cooling output turns on. If the outdoor temperature and humidity conditions are below the set point of the economizer control the lag unit economizer will operate instead of the compressor. If outdoor conditions are not acceptable for free cooling the compressor will automatically operate on compressor Stage 1 partial capacity instead of the economizer.

3rd cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 2. On a call for 3rd Stage cooling the lead unit economizer will close and the compressor will operate on full capacity compressor Stage 2.

4th cooling set point is 2F (default setting, user selectable 2- 3F) warmer than Stage 3. On a call for 4th Stage cooling the lag unit economizer will close and the compressor will operate on full capacity compressor Stage 2.

Manual	2100-563C
Page	10 of 40