York YLAA0041 Manual page 130

SECTION 7 – UNIT CONTROLS
Motor Protector/High Pressure Cutout Fault
The Motor Protector/High Pressure Cutout protects the
motor from overheating or the system from experienc-
ing dangerously high discharge pressure. This fault
condition is present when CR1 (SYS 1) or CR2 (SYS
2) opens causing 0 VDC to be read on the input. The
fault condition is cleared and will allow to restart the
system when a 30 VDC signal is restored to the input
by closing CR1 or CR2. This fault will shut down the
system 0.5 seconds after the relay opens. This fault will
only occur when a system is running. Following are the
messages for both systems.
S Y S 1 M P / H P C O
S Y S 2 M P / H P C O
Motor Protector/High Pressure Cutout Inhibit
The Motor Protector/High Pressure Cutout Inhibit pre-
vents the system from trying to start when a motor pro-
tector is faulted or the mechanical high pressure cutout
is open. This inhibit condition is present when CR1
(SYS 1) or CR2 (SYS 2) opens causing 0 VDC to be
read on the input. The inhibit condition is cleared and
will allow to restart the system when a 30 VDC signal
is restored to the input by CR1 or CR2 closing. This
inhibit will only occur when a system is not running.
Following are the messages for both systems.
S Y S 1 M P / H P C O
S Y S 2 M P / H P C O
High Motor Current
The Motor Protector/High Pressure Cutout Inhibit pre-
vents the system from starting when a motor protec-
tor is faulted or the mechanical high pressure cutout is
open. This inhibit condition is present when CR1 (sys
1) or CR2 (sys 2) opens, causing 0 V to be read on the
input. The inhibit condition is cleared and allows the
system to start when a 30 V signal is restored to the
input by CR1 or CR2 closing. This inhibit only occur
s when a system is not running. The following are the
messages for both systems.
S Y S 1 H I G H
S Y S 2 H I G H
130
F A U L T
F A U L T
I N H I B
I N H I B
M T R C U R R
M T R C U R R
Low Superheat Cutout (EEV Mode Only)
The Low Superheat Cutout protects the compressors
from liquid flowing back due to low suction superheat.
This safety is only active when EEV is selected as the
expansion valve type. This safety is ignored for the
first 15 seconds of system run time.
Two events can trigger this safety. The first event is
when the suction superheat is lower than 2.0°F for 3
seconds. The second event is when the LLSV is closed
10 times in 2 minutes due to low superheat. See the
LLSV control section for further details. Following are
the messages for all systems.
S Y S 1 L O W S U P E R H E A T
S Y S 2 L O W S U P E R H E A T
Sensor Failure Cutout (EEV Mode Only)
The Sensor Failure Cutout prevents the EEV from run-
ning when the sensors measuring superheat are not
functioning properly. This safety is only active when
EEV is selected as the expansion valve type. This
safety is ignored for the first 15 seconds of system run
time. This safety will shut down a system if either the
suction temperature or suction pressure sensors read
out of range high or low. The condition must be pres-
ent for 3 seconds, to cause a system shutdown. This
safety will lock out a system the first time and will not
allow automatic restarting. Following are the messages
for all systems.
S Y S 1 S E N S O R
S Y S 2 S E N S O R
Anti-Vacuum Low Pressure Cutout
When the suction pressure falls below the anti-vacuum
low pressure cutout for more than the programmed de-
lay time 3 times in 90 minutes, this safety will shut
down a system. This fault is a standard system fault.
Following are the messages for both systems.
S Y S 1 A T V S U C T
S Y S 2 A T V S U C T
Fault and Inhibit Codes and Reset
Table 14 shows the fault and inhibit codes and how to
reset them. There are three ways to reset the fault and
inhibit. See Table 15 for more information.
FORM 150.72-ICOM6
ISSUE DATE: 08/03/2022
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JOHNSON CONTROLS