SMX II Controls For Direct Expansion Air Conditioning Systems

The SMX II is a microprocessor-based electronic control for use with Cruisair direct expansion air conditioning systems. It can be retrofitted in the field to replace any electromechanical switch assembly.

The SMX II has a noncorrosive ABS cover and soft-touch membrane switches. All keys are clearly labeled, making operation simple. The large, easy-to-read digital display shows setpoint or cabin temperature and also is used to give information on operating parameters and fault code warnings. Small LEDs are used to indicate system status. Switchplates, which are available in black, brown, white or beige, must be ordered separately.

For normal operation, it is only necessary to turn the system on and select the desired setpoint. The user can select cooling only, heating only, or automatic changeover between cooling and heating. Fan speed is automatically controlled, or can be manually set. Factory settings may be changed, with user-programmable commands, permitting the boatowner to fine-tune the system for personal preferences. Programming modes are accessed by pressing special combinations of keys.

Programmable features Include AC line voltage calibration, temperature calibration, compressor restart time delay, continuous or intermittent fan operation, low and high fan speed adjustment, compressor response differential, Fahrenheit or Celsius temperature display The system's nonvolatile memory retains all user-programmed settings, even when the power is switched off.

The SMX II constantly monitors line voltage and refrigerant pressures. Whenever out-of-tolerance conditions are sensed, the SMX II computer displays a visual warning and shuts the system down to prevent damage.

Software upgrades for the SMX series controls are released periodically by Cruisair, and new software can be installed in the field by exchanging plug-in EPROMs.

The dehumidification program ensures, even when no one is aboard, the boat stays dry, eliminating mold, mildew and odor.