Johnson Controls 100 Series User Manual

JOHNSON CONTROLS
78
FORM 100.50-NOM12
ISSUE DATE: 04/02/2019
SECTION 5 – SEQUENCE OF OPERATION
Low Pressure Cutout (LPCO) Switch
• Each compressor system contains a LPCO.
• The IPU board monitors the status of the LPCO
whenever a compressor system is in operation.
• The LPCO status is ignored for the rst 45 sec-
onds after a compressor system is started to al-
low the suction pressure to build up to a stabilized
condition.
• Wiring of the LPCO is shown in Figure 37 on
page 77 (Comp Sys #1 shown). Refer to the
unit's wiring diagrams for other systems.
• If the LPCO faults/opens while a compressor sys-
tem is in operation, compressor operation termi-
nates immediately, and a compressor LPCO trip
occurs. Once the LPCO switch closes, normal
compressor operation continues.
• At this time, the IPU board starts a 120 minute
timer. When two or more LPCO trips occur with-
in this 120 minutes, a Compressor LPCO Safety
Lockout occurs.
• A Compressor LPCO Safety Lockout requires a
manual reset through the IPU board.
Resetting a Compressor System Safety
Lockout
• Once a compressor system experiences either
a Compressor Safety Lockout or a Compressor
LPCO Safety Lockout, a manual reset is required
• Resetting a Safety Lockout is achieved by per-
forming the following steps:
a. Leave the control/rocker switch in the ON
position.
b. Press the COMPRESSOR SYSTEMS key.
c. Use the left/right arrows to navigate to the
compressor system with the lockout.
d. Use the up/down arrows to find the screen that
displays Compressor Sys # State Lockout.
The # symbol is replaced by the compres-
sor system number, 1, 2, or 3 in the actual
display on the unit.
e. Press the PROGRAM key and use the left/
right arrows, navigate until the top line of
display shows Program - Compressor Sys-
tem #.
On older versions of software, resetting
the Comp Sys # Safety Lockout was done
in the Options menu. If the reset is not
found in the Program menu, try nding
it in the Options menu.
f. Press the  key and enter the password when
prompted (9725) and then press the  key
again.
g. The display should now show
Program-Compressor System #: Check to Edit
Compressor Sys # State: Lockout
h. Press the  key and use the left/right arrows
to change from Lockout to Run, and press
the  key again.
1. When the compressor state returns to
Lockout, that means a safety switch is
still open and further troubleshooting is
required.
2. When the compressor state remains in
Run, press the X key and exit out of
the PROGRAM-COMPRESSOR SYS-
TEM # menu.
i. The Compressor System Lockout has now
been cleared and reset.
Suction Temperature Monitoring
• On the Series 100 unit, each compressor system
contains a suction line temperature sensor.
• This sensor monitors the temperature of the suc-
tion line while a compressor system is operating.
• When one compressor in a system is running and
the suction line temperature falls below the low
suction temperature limit (37.0°F for R-410A) for
10 seconds, the compressor shuts OFF. The sec-
ond compressor in the system is allowed to start
when the suction line temperature rises above the
low suction temperature limit.
• The compressor remains off until the suction line
temperature rises above the suction temperature
low limit by 10.0°F for 10 minutes.

Johnson Controls 100 Series Specifications

General

Brand	Johnson Controls
Model	100 Series
Category	Air Conditioner
Language	English