Bard MC4000 installation instructions StageCompressor Units No Economizer

6.2-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 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 continue to operate as long as outdoor conditions are acceptable, and the compressor will operate on compressor Stage 1 partial capacity. If outdoor conditions are not acceptable for free cooling the lead unit compressor will automatically be operating on compressor Stage 1 partial capacity and will go to Stage 2 full capacity operation.

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 on compressor Stage 1 partial capacity. If outdoor conditions are not acceptable for free cooling the lag unit compressor will automatically be operating on compressor Stage 1 partial capacity and will go to Stage 2 full capacity operation.

COOLING OPERATING SEQUENCES FOR NON-ALTERNATING LEAD/LEAD/LAG/ LAG CONFIGURATION

Note: Heat pumps cannot be operated in Non-Alternating Lead/Lead/Lag/Lag sequence. Selecting Heat Pump = Yes will override a Non-Alternating selection and force system to Alternating Lead/Lag/Lead/Lag sequence.

1.2-Stage Compressor Units No Economizer

1st stage1st 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 compressor will start in compressor Stage 1 partial capacity operation.

2nd cooling set point is 4F (default setting, user selectable 2-6F) warmer than Stage 1, at which time the lead unit compressor will switch to compressor Stage 2 full capacity.

3rd cooling set point is 2F (default setting, user selectable 2-3F) warmer than Stage 2. On a call for 3rd Stage cooling the blower of the lag unit will come on immediately (if not already on – See Blower Operation), and Stage 3 LED will blink for 10-seconds before going solid, and then the lag unit compressor will start in compressor Stage 1 partial capacity.

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.

2.1-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 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 lead unit Y2 cooling output turns on. The lead unit economizer will close and the compressor will operate. If the compressor is already running from 1st stage cooling call due to outdoor conditions being outside of free cooling range no action occurs at 2nd stage set point.

Manual	2100-563C
Page	11 of 40