Figure 3. Control Board Detail - Industrial Climate Engineering SlimPac ECUA12 Installation & Operation Manual

High Pressure Switch
The high pressure switch is mounted on the liquid line. It is electrically connected to a lockout circuit
on the board which shuts down the system if the refrigerant pressure rises to 625 PSIG. This protects
the unit if airflow through the condenser is blocked or if the outdoor fan motor fails.
Although the contacts of the high pressure switch close when the refrigerant pressure falls to approxi-
mately 450 PSIG, the system must be manually reset once the lockout circuit is activated. A manual
reset is necessary to prevent harmful short-cycling. To reset switch, turn primary power off, then back
on or turn thermostat system switch off, then back on.
Low Pressure Switch
The low pressure switch is mounted on the compressor suction line. It is designed to open if the re-
frigerant pressure drops to 40 PSIG; it resets when the pressure rises to 60 PSIG. The switch protects
the unit if airflow through the indoor blower is impeded, if the blower motor fails, or if there is a loss
of refrigerant.
LEDs
Post Purge Wheel

Figure 3. Control Board Detail

13
Delay on Make
(Compressor Time Delay) Wheel
ICE SlimPac ECUA12-18 I&O Manual 03/2019 Rev.2