6 53-22130A100
131 EISENHOWER LANE NORTH
LOMBARD, ILLINOIS 60148-5413
630-268-0010 / 1-800-251-2408
ELECTRONIC CLIMATE CONTROL
INTELLITEC
TheSHORT INDICATOR operatesin the OFF and TEST modes of the TEST SWITCH.
The Control Module also includes protection circuitry to eliminate the possibility of “short-cycling” the A/C
compressors. Short-cyclingcauses unduestress onthecompressor motorwhen refrigerantpressuresare not
allowed to stabilized prior to restarting the compressor. A two minute timer is incorporated in each of the
controlsystems for thefrontand rear A/Ccompressors. Thetimer is started eachtime one of threeconditions
is encountered: 1) If the Control Module shuts down the associated A/C compressor during a the shedding
sequence,or ifthe ambienttemperature hasreached thesetpoint. 2) Ifthe 120VACline currentsensed bythe
Current Sensor goes below 1 Amp. This will occur during an interruption of power, if the generator is not
running,or if theshorepower cord isnotplugged in. 3) If +12VDC power is notapplied to the ControlModule.
TheControl Moduledoes notallowthe compressorto bere-energizeduntil thetwo minuteperiodhas elapsed.
If during this period, the coach requires cooling or if the unit is recovering from load shedding, the Control
Module will signal the ECC Thermostat to alternately flash the ON and SHED indicators on the control panel
until the period has elapsed. After the two minute period has elapsed the system will return to normal
operation.
An important feature included in the Control Module circuitry is the Automatic Load Shedding function. This
circuitrymeasures the total current being drawn byallof the 120 VAC operated equipment in the coach being
fedthrough the main panel. The Current Sensor is mounted in the mainpaneland supplies an input signal to
theControl Module. When enough 120 volt appliances are operated so that the current exceeds 30 Amps for
more than approximately 3 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 inthe following order:
1. RearA/C compressor (if running)
2. FrontA/C compressor (if running)
3. RearA/C fan (if running)
4. Front A/C fan
When the Control Module sheds any of the loads, it returns a signal to the ECC Thermostat to light the
correspondingfront or rearSHED indicator. Basedonthe shedding sequence,the rear SHED lightwill always
be the first to light. If enough appliances are operated to generate a load current of 30 Amps, the Control
Modulewill proceed through the entire shedding sequence and essentially shut down both A/C compressors
andfans. (It isimportant tonote thatif theControlModule hasshed allfour loadsand thelinecurrent continues
to exceed the 30 Amp limit, it is likely that the 30 Amp line breaker will open.)
ALTERNATINGOPERATION:
If the total current being drawn is such that only one A/C can operate, and the ECC Thermostat continues to
demandthat both A/C compressors operate, the ControlModulewill alternate operation of the front andrear
A/C compressors every 30 minutes. When the line current is low enough to allow operation of both air
conditioners,the Control Modulewillrestore their operationina reverse order tothe shedding sequence. The
front or rear SHED indicators on the ECC Thermostat will remain lit until the corresponding A/C compressor
andfan are restoredtonormal operation.
