16
E SERIES INSTALLATION MANUAL
Standard Microprocessor Control Features
Startup
The unit will not operate until all the inputs and safety controls are checked for normal conditions. At first power-up, a
four-minute delay is employed before the compressor is energized.
Component Sequencing Delays
Components are sequenced and delayed for optimum space conditioning performance.
Accessory Relay
An accessory relay on the control board allows for field connection of solenoid valves, electronic air cleaners, etc. The
accessory relay has a normally open output and a normally closed output.
Short Cycle Protection
The control employs a minimum "off" time of four minutes to provide for short cycle protection of the compressor.
Condensate Overflow Protection
The E Series control board incorporates an impedance sensing liquid sensor at the top of the drain pan. Upon a con-
tinuous 30-second sensing of the condensate, compressor operation is suspended (see Fault Retry), and the condensate
overflow lockout LED begins flashing.
Shutdown Mode
A 24VAC common signal to the “shutdown” input on the control board puts the unit into shutdown mode. Compressor,
hot water pump and fan operation are suspended.
Safety Controls
The E Series control receives separate signals for a high pressure switch for safety, a low pressure switch to prevent
loss of charge damage, and a low suction temperature thermistor for freeze protection. Upon a continuous 30-second
measurement of the fault (immediate for high pressure), compressor operation is suspended, the appropriate lockout LED
begins flashing. (Refer to the "Fault Retry" section below.)
Testing
The E Series control allows service personnel to shorten most timing delays for faster diagnostics. (Refer to the Field
Selection DIP switch SW2-1 on page 18.)
Fault Retry
All faults (except for low RPM faults with the ECM2 fan motor) are retried twice before finally locking the unit out. An
output signal is made available for a fault LED at the thermostat. The “fault retry” feature is designed to prevent nuisance
service calls.
Diagnostics
The E Series control board allows all inputs and outputs to be displayed on the LEDs for fast and simple control board
diagnosis. (Refer to the Field Selection DIP Switch SW2-1 on page 18.)
Resistance Heat Control
(208-230 Units)
The electric heat control module contains the appropriate high-voltage control relays. Control signals energize the relays
in the proper sequence, and the LED display board indicates which stages are energized.
Hot Water High Limit
(Domestic Hot Water Option)
This mode occurs when the hot water input temperature is at or above 130°F for 30 continuous seconds. The DHW limit
status LED on the unit illuminates and the hot water pump de-energizes. Hot water pump operations resume on the next
compressor cycle or after 30 minutes of continuous compressor operation during the current thermostat demand cycle.
