Carrier 30GTN Service And Troubleshooting Manual page 17

CEBD430351-0396-01C
J1
J2
J4 J3
J5
RED LED - STATUS
The capacity routine runs every 30 seconds. The routine
attempts to maintain the Control Point at the desired set point.
Each time it runs, the control reads the entering and leaving
fluid temperatures. The control determines the rate at which
conditions are changing and calculates 2 variables based on
these conditions. Next, a capacity ratio is calculated using
the 2 variables to determine whether or not to make any changes
to the current stages of capacity. This ratio value ranges from
LEN
STATUS
J6
GREEN LED -
LEN (LOCAL EQUIPMENT NETWORK)
Fig. 15 — Energy Management Module
−100 to + 100%. If the next stage of capacity is a compres-
sor, the control starts (stops) a compressor when the ratio
reaches + 100% (−100%). If the next stage of capacity is an
unloader, the control deenergizes (energizes) an unloader when
the ratio reaches + 60% (−60%). Unloaders are allowed to
cycle faster than compressors, to minimize the number of
starts and stops on each compressor. A delay of 90 seconds
occurs after each capacity step change.
17
J7
TEST 2