Marine Air Systems ECU-Maxx, Operation Manual

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PAGE 23
ECU-Maxx VER:10a 12/1/97
ECU-M
AXX
O
PERATIONS
M
ANUAL
S
YSTEM
I
NPUTS AND
O
UTPUTS
Internal Sensor Inputs
The ECU-Maxx has four internal sensors:
1. Control Panel Air Temperature Sensor
2. Control Panel Ambient Light Sensor
3. AC Line Voltage
4. System Amperage
External Sensor Inputs
The standard ECU-Maxx has inputs for three external sensors. Please
refer to Figure 3 for a graphic representation of where these inputs are.
1. Alternate Air / Outside Air Temperature Sensor
2. High Freon Pressure Input (Optional)
3. Low Freon Pressure Input (Optional)
System Outputs
The fan motor is connected to this output. Varying the output voltage controls
fan speeds. The fan can be configured for two different modes of operation:
1. On continuously when the system is on.
2. On when the compressor is running and off when the compressor is not
running. Note that the fan shuts off 15 seconds after the compressor during
normal heating and cooling. If the CAL Rod Heater is installed, the fan
runs for 4 minutes after the heater is turned off. The fan also has a 4 minute
shut-off delay in moisture control mode.
This output can be configured for two different modes of operation:
1. On continuously when the system is on and the fan is operating.
2. On when the compressor is ON and OFF when the compressor is OFF.
This setting reduces pump wear. The pump will cycle off 2 minutes after
the compressor in this mode.
The valve output is turned on when the control senses the need for heating.
The water temperature must be greater than the low water limit to activate
the valve, if the optional CAL rod heater has been installed.
The compressor output is on when the ECU-Maxx is calling for heating or
cooling. The compressor is not on in the heating mode if heat is being supplied
by the optional electric CAL rod heater.
The heater output is on when heat is called for and the water temperature
is equal to or less than the low water limit, and the heater is installed. Low
sea water temperature will cause the unit to switch to the electric heater
(if installed). When the heater option is selected, the water inlet option
should also be installed.
The compressor start relay is included in the control outputs. The ECU-
Maxx monitors compressor starting time and run current to assure proper
operation of the relay and efficient compressor start-up. Low line voltage
cannot cause the relay to reenergize accidentally as happens with conven-
tional start relays. A start relay malfunction will cause compressor shut
down and lock out to prevent compressor failure.
VALVE
HEATER
COMP.
START
RELAY
PUMP
FAN