Electronic Control Board Mode Of Operation - Industrial Climate Engineering SlimPac ECUA12 Installation & Operation Manual

1.7

Electronic Control Board Mode of Operation

Normal
24 VAC power must be continuously applied to "R" and "C". Upon a call for cooling "Y" and with the
high pressure switch (HPS) closed, the compressor will be energized. (Note: See the delay on make
feature.) The compressor will remain energized during the 3 minute timed low pressure by-pass cycle. If
the low pressure switch (LPS) is open after the 3 minute by-pass cycle, the compressor will de-energize.
Lock-out
If either of the fault conditions (LPS or HPS) occurs twice during the same call for cooling, the control
board will enter into and indicate the lockout mode. In the lockout mode, the compressor is turned off.
If there is a call for indoor air flow "G", the blower remains energized, the alarm output is energized and
the status LED will blink to indicate which fault has occurred. When the lockout condition is cleared, the
unit will reset if the demand for the thermostat is removed or when the power is reset. With the control
board, the user can now have either normally closed or normally open remote alarm dry contacts. The
air conditioners are factory wired to be normally open.
Delay on Break
If the compressor is de-energized due to a loss of a cooling "Y" call or the first fault, the unit re-start
will be delayed 3 minutes from the time the contactor is de-energized. (Note: There is no delay on
break if the lockout condition is reset.)
Delay on Make
On initial power up only, the unit will wait 0.03 to 10 minutes from the cooling "Y" call before al-
lowing the contactor to energize. The delay can be adjusted by the DOM wheel on the board. Factory
recommended wait is 3 minutes.
Low Pressure By-Pass Time
When starting, the low pressure switch (LPS) fault condition will be by-passed for 3 minutes before
the contactor is de-energized.
Post Purge
Upon a call for indoor airflow "G" the blower will energize immediately. When in the cooling mode,
the blower will remain energized for 10 to 90 seconds (adjustable) after the compressor has been de-
energized. The time period can be changed by fan purge wheel on the board. Factory setting is 90 seconds.
LED Indicator Lights
COLOR
Green
Red
Red
Red
Low Ambient Control
The low ambient control permits cooling when outdoor ambient temperatures are low. The control uses
a reverse-acting high pressure switch to cycle the condenser fan motor according to liquid refrigerant
pressure conditions. Switch closure and fan operation occurs when the pressure reaches 400 PSIG. The
switch opens again when the refrigerant pressure falls to 245 PSIG. Therefore, the outdoor fan always
starts after the compressor, and it will cycle frequently during normal operation at low outdoor
conditions.
ICE SlimPac ECUA12-18 I&O Manual 03/2019 Rev.2
TYPE STATUS
Power Contstant On
Status Contstant On
Status 1 Blink
Status 2 Blinks
DESCRIPTION
24 VAC power has been applied
Normal operation
High pressure switch has opened twice
Low pressure switch has opened twice
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