ELECTRONIC CLIMATE CONTROL II
SERVICE MANUAL Part No’s. 00-00855-000 / 00-00856-000
Intellitec
1485 Jacobs Rd.
Deland, FL 32724
386.738.7307
www.Intellitec.com
- 6 -
P/N 53-00855-856 Rev. C 080819
they are shorted, the system will not operate. To help diagnose a fault with this line, the control module includes two LED
indicators, “IPX OK” and “IPX FAULT”, associated with this circuit. Under normal operation, the “IPX OK” light should be
lit. This shows the presence of 12 volts and signal available at the output of the control module. If the IPX
communication line between the thermostat and the control module is shorted to ground or +12 volts, the “IPX OK” LED
will be out and the “IPX FAULT” LED will be lit. If neither is on, the 12 volt supply is probably missing.
WIRING FAULT INDICATOR:
The 12 volt wires feeding the air conditioners are protected from short circuits. If any of these wires are shorted to
ground, the
“WIRING FAULT”
indicator
will be lit indicating the short. To help locate the short, the plugs feeding the air
conditioners should be unplugged, one at a time, to see which cable is at fault. When the shorted cable is unplugged, the
“WIRING FAULT”
indicator will go out and the other air conditioner will operate normally. The individual wires of the
shorted plug can be tested for shorts to find which one is at fault.
The
“SHORT”
indicator operates in the
“OFF”
and
“TEST”
modes of the
TEST SWITCH
.
The Control Module also includes two minute timers for each air conditioner to eliminate the possibility of short-cycling the
A/C compressors. Short-cycling causes undue stress on the compressor motor when refrigerant pressures are not
allowed to stabilized prior to restarting the compressor.
The timer is started each time one of three conditions is encountered:
1) If the Control Module shuts down the associated A/C compressor during the shedding sequence.
2) If the 120 VAC line voltage sensed by the Line Voltage Sensor goes off.
This will occur during an interruption
of power, if the generator is not running, or if the shore power cord is not plugged in.
3) If the unit is recovering from load-shedding, the Control Module will signal the ECC Thermostat to alternately
flash the red
SHED
indicator on the control panel. The Control Module will not allow the compressor to be re-
energized until the two-minute period has elapsed.
LOAD SHEDDING:
An important feature included in the control module is the automatic load shedding function. This circuitry measures the
total current being drawn by all of the 120 VAC operated equipment in the coach being fed through the main panel. The
current sensor is mounted in the main panel and supplies an input signal to the control module. When enough 120 VAC
appliances are operated so that the current exceeds 30 Amps for more than approximately 5 seconds, the control module
begins to shed (shut off) the A/C compressors and fans to bring the current back below the 30 Amp limit. This prevents
nuisance tripping of the main 30 Amp breaker.
The shedding sequence occurs in the following order:
1. (A/C2) compressor (if running)
2. (A/C1) compressor (if running)
3. (A/C2) fan (if running)
4. (A/C1) fan
When the Control Module sheds any of the loads, it returns a signal to the thermostat to light the corresponding A/C1 or
A/C2
”SHED”
indicator. Based on the shedding sequence, the A/C2
”SHED”
indicator will always be the first to light. If
enough appliances are operated to generate a load current of 30 Amps, the control module will proceed through the entire
shedding sequence and essentially shut down both A/C compressors and fans.
It is important to note that if the
control module has shed all four loads and the line current continues to exceed the 30 Amp limit, it is likely that
the 30 Amp line breaker will open.
Current
Sensor
