System Fault (Safety) Status Messages - York eco2 YCAS0425EB Installation Operation & Maintenance

the chiller must be manually reset. See Section 8.2 (page
142).
Flow Switch Open:
S Y S # N O
S Y S # N O
Closure of the flow switch(es) is monitored to check that
flow is present in the evaporator when a compressor is
running. Any external cycling devices fitted by the cus-
tomer are connected in series with the flow switch(es).
YCAS 2-system chillers have a single flow switch wired
to the control panel. YCAS 3-system chillers have two
flow switches mounted together with one wired to each
control panel. YCAS 4-system chillers have two flow
switches, one mounted in the flow from each evaporator
and wired to the associated control panel. If the flow
switch opens, all systems controlled by the panel it is
connected to will shut down and a NO RUN PERM (Per-
missive) message will be displayed. Closing of the flow
switch, when flow is present, will cause the message to
disappear and auto-restart to occur.
Never bypass a flow switch. This will
cause damage to the chiller and void
any warranties.
2.6 SYSTEM FAULT (SAFETY)
STATUS MESSAGES
A System Fault will shut the affected system down
whenever a preset safety threshold is exceeded for 3
seconds. Automatic restart will occur after the first 2
shutdowns when the anti-recycle timer times out and
temperature demand exists. After any combination of
3 Manual Reset Safeties in a 90 minute time period, the
affected system will shut down and lock out on the last
fault. When one or more systems are shut down on one
of these safeties, a message will appear on the Status
display informing the operator of the problem.
The High Motor Current Safety is a
unique safety which will lock out a sys-
tem after only a single fault.
To reset a locked-out system, turn the System Switch
for the affected system to the OFF position, then back
to the ON position (see Section 1.11, Fig.48 for switch
locations).
YORK INTERNATIONAL
R U N P E R M
R U N P E R M
Before returning a locked-out system
to service, a thorough investigation of
the cause of the fault should be made.
Failure to repair the cause of the fault
while manually allowing repetitive re-
starts may cause further expensive
damage to the system.
High Discharge Pressure Cutout:
S Y S # H I G H
S Y S # H I G H
The Discharge Pressure Safety prevents system pres-
sure from exceeding safe working limits. This safety is
a backup for the mechanical High Pressure Cutout in
each system. The Discharge Pressure Safety is program-
mable for a range of values below the system upper
limit (see Section 8.2 / Page 139, High Discharge Pres-
sure Cutout for more details).
High Discharge Temperature Cutout:
S Y S # H I G H
S Y S # H I G H
This safety protects the compressor rotors from dam-
age due to overheating, expansion, and breakdown of
the oil film seal between the rotors. It also protects
against excessive oil temperature in the discharge oil
separator.
For the first 4 seconds of operation discharge tempera-
ture is ignored. After 4 seconds of operation the com-
pressor will shut down if the discharge temperature ex-
ceeds 127°C (260°F).
High Oil Differential Pressure Cutout:
S Y S # H I G H
S Y S # H I G H
The High Oil Pressure Differential Safety protects the
compressors against loss of proper lubrication due to
oil return line blockage. The "differential oil pressure"
for this safety is computed by measuring discharge (oil
separator) pressure and subtracting oil pressure return-
ing to the compressor (Discharge - Oil = Oil PSID).
Under typical operation, the oil pressure differential
display will read less than 1.7 bar (25 PSID). If oil pres-
sure at the compressor drops due to filter blockage, the
differential pressure on the display will increase and
when the maximum limit is reached the compressor will
be shut down.
FORM 201.18-NM8
D S C H P R E S
D S C H P R E S
D S C H T E M P
D S C H T E M P
O I L D I F F
O I L D I F F
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