MCC Control Board / DDC Control Board Replacement ASY-405-XXX / 290000201

MCC Control Board / DDC Control Board Replacement ASY-405-XXX / 290000201

MCC Control Board
The MCC Control Board is a fully-compatible replacement for the DDC® control board, offered with some Marine Air Systems® chillers. MCC is a complete, standalone chiller controller. In addition, up to 6 MCC control boards can be networked together using the MCC Master control board to operate a large, multi-stage chiller system.

Marine Air Systems and DDC are a registered trademarks of Dometic Corporation

The Marine Chiller Control, identified in this document as MCC, can be used as a standalone or staged chiller controller to regulate loop water temperature in tempered water
systems. MCC also provides a level of protection against system damages caused by high or low
refrigerant pressures, water flow problems, freezing of the compressor, and low line voltage.
The MCC can be used to control directly connected compressors, VFD’s, reversing valves,
electric heaters and system pumps.

Wiring

Controls must be connected as shown in the wiring diagram contained in this manual.
High limit, freeze and return sensors must be the appropriate Microair sensor listed in the
diagram. Switch inputs are dry contact only and must not have any outside connections to
voltage or current sources. External contactors must be used for water pumps over ½ HP,
compressors over 2 HP, and for electric heaters.

Stand Alone Operation

Power Application
When power is first applied, the display will show the firmware revision for 2 seconds
and then go blank if the mode switch is in the off position. Change the mode switch to select
heating or cooling.

Reversing Valve Operation
If a cycle is called within 75 seconds of a power restore or termination of a cycle, the
reversing valve will toggle to equalize system pressures. This toggle will not occur if electric heat
is enabled. The reversing valve will remain active when the compressor is active in heat mode.

Water Pump Operation
The circulating water pump (CWP) output will remain in operation whenever the mode
switch selects heat or cool. The seawater pump (SWP) output will cycle with the compressor or
run continuously depending on the “CON, dc” program parameter setting. See the program
parameters section in this manual for more information.
September 28, 2020 5 Rev 2.02

Operating Modes
When heat or cool is selected on the mode switch, the display will alternate between
showing “SUP” (supply or outlet temperature measured by the freeze sensor), followed by the
temperature and “rtr” (return or inlet temperature) followed by the temperature. If the water
temperature deviation is 2° or greater from the set point, then the MCC will start a cycle. The
compressor will start and continue to operate until the loop return temperature reaches set
point.

Direct replacement for Dometic DDC control board 4220002