Product Overview
Specifications/Features for Basic Controller
MC4002 Basic Controller
• Input power: 18 to 32VAC, 60/50Hz, power is supplied from A/C #1 and/or A/C #2.
• Isolation circuitry: no line or low voltage phasing required.
• Backup power: connection for -24VDC or -48VDC (-20 to -56V) maintains microprocessor operation, front panel
indication, and alarm relay operation during commercial power outages.
• Digital display: 4-character LCD
• Temperature display: F or C
• HVAC outputs: Form A (NO) relays (1A @ 24VAC).
• Cooling control stages: 2 for each A/C unit (4 total).
• Heating control stages: 1 for each A/C unit, 2 for each heat pump if so configured.
•
Dehumidification circuit: requires optional humidity controller that closes on-rise as input signal, Bard Part #8403-038
recommended. Both HVAC units must be equipped with electric heat for this sequence to work properly.
• Locking feature, allows controller to be “locked” so no unauthorized changes to programming can be made.
• Operating temperature range: 0 to 120F (-18 to 49C)
• Storage temperature range: -20 to 140F (-29 to 60C)
• Temperature accuracy: +/- 1F from 60-85F (16-30C)
+/- 1% outside 60-85F
• Lead/lag changeover time: 0 to 30 days
• Timing accuracy: +/- 1%
• Inter-stage time delay: 10 seconds between stages
• Inter-stage differential: Adjustable – See Controller Programmable Features (Page 6).
• On-Off differential: – See Controller Programmable Features (Page 6).
• Cooling set point range: 65 to 90F (18 to 32C)
• Comfort setting-Cooling 72F, Heating 68F, for 1 hour
• Dead band (difference between cooling and heating set points): 2F to 40F (1C to 24C)
•
Fire/smoke interface: standard NC circuit jumper, remove for connection to building system control, shuts down both
A/C units immediately. Field supplied fire/smoke device must have normally closed (NC) dry contact rated at 2A 24VAC
minimum. Shielded cable (22-gauge minimum) must be used and shield grounded to controller enclosure.
• Generator run feature, inhibits lag A/C unit from operating if generator is operating (to limit amperage).
• Memory: EEPROM for set point and changeable parameters (maintains settings on power loss).
• Space temperature sensors: 1 local is standard, will accept up to 2 optional 35-foot remote sensors. When multiple
sensors are used temperatures are averaged.
•
LEDs for basic controller: Lead unit, Cooling stages 1 through 4, Heating stages 1 through 4, Dehumidification operation.
•
Six (6) Push-button controls: On/Off switch-Change lead unit-Increase and Decrease set points-Program/Save-Comfort.
• Controller Enclosure: 20-gauge pre-painted steel, 9.25"W x 13.50"H x 3.00"D, hinged cover, thirteen (13) .875"
diameter electrical knockouts.
Specifications/Features for Alarm Boards
MC4002-A w/Optional Base Alarm Board (Inputs/Outputs)
• Refrigerant alarm from A/C #1, input
• Refrigerant alarm from A/C #2, input
• Power loss alarm A/C #1, Form C (SPDT) output
• Power loss alarm A/C #2, Form C (SPDT) output
• Smoke/fire alarm, Form C (SPDT) output
• Low temperature alarm, Form C (SPDT) output
• 1
st
stage (H1) high temperature alarm, Form C (SPDT) output
• Refrigerant system lockout A/C #1, Form C (SPDT) output
• Refrigerant system lockout A/C #2, Form C (SPDT) output
MC4002-B w/Enhanced Version Alarm Board (Additional Outputs)
• All alarm inputs/outputs same as base version above, plus:
• 2
nd
stage (H2) high temperature alarm, Form C (SPDT) output
• 2
nd
stage cooling alarm, Form C (SPDT) output
• Controller system failure alarm, Form C (SPDT) output
• Emergency ventilation economizer outputs, Form A (SPNO) for both A/C #1 and A/C #2
o Emergency ventilation option for either air conditioner
with refrigerant alarm @ H1 high temp alarm set point
o Emergency ventilation option for both air conditioners
@ H2 high temp alarm set point
Note: All alarm/output relays are dry contacts rated
1A @ 24VAC, 1A @ 30VDC, 0.5A @ 150VDC
Alarm relays can be wired for NO (close on alarm) or
NC (open on alarm) strategy.
Alarm relays can be used individually if there are
enough available building alarm points, or can be
arranged into smaller groups or even a single group so
that all alarm capabilities can be utilized.
When multiple alarms are grouped together and
issued as a single alarm, there will be no off-site
indication of which specific problem may have
occurred, only that one of the alarms in the group has
been triggered. The individual alarm problem will be
displayed on the LED display on face of the controller.
Form No. S3548-1116
Supersedes NEW
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