York Millennium YCAJ150 Installation Operation & Maintenance Download

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FORM 150.65-NM4

YORK INTERNATIONAL

NOTE: Do not confuse FLA and RLA. FLA (full load

amps) is approximately 1.2 x RLA. RLA (run-
ning load amps) specified on the motor name-
plate, is typical current demand under rated op-
erating conditions in a fully loaded system. There-
fore, do not expect to see 100% FLA when the
system is fully loaded In this condition, currents
may run approximately 65 - 85% FLA.

INDIVIDUAL START INHIBIT SAFETIES

An Individual System Start Inhibit Safety will shut the
respective system down on a fault when the safety thresh-
old is exceeded and allows automatic restart after the
condition causing the shutdown clears. Restart will oc-
cur only after anti-recycle timers are satisfied and de-
mand requires.

When the chiller is shut down on one of these safeties,
a message will appear on the STATUS display informing
the operator of the problem. This is accessible by press-
ing the STATUS key.

Low Oil Temperature Inhibit Safety

The low oil temperature safety assures the compressor
is not allowed to start until the oil is free of liquid refriger-
ant. This is accomplished by assuring that the oil tem-
perature is a minimum of 15°F (8.3°C) above ambient
temperature.

In effect, this safety assures that the compressor oil
heater is operating and that it has been on long enough
after power application for all refrigerant to have been
expelled from the oil.

NOTE: This safety will only be operational if the chiller

is equipped with an I/O Expansion Board.

An example of the High Oil Temp safety display is shown
below.

AUTOMATIC RESET SAFETIES

An Automatic Reset Safety will shut the entire chiller
down on a fault when the safety threshold is exceeded
and allows automatic restart after the condition causing
the shutdown clears. Restart will occur only after anti-
recycle timers are satisfied and demand requires.

A reset hysteresis is built in so repetitive faulting and
clearing will not occur in a short time period. An ex-
ample would be if ambient temperature dropped below
the cut-out, temperature would have to rise 5°F (2.8°C)
above the cut-out before the fault lockout would clear
and restart can occur.

causes high internal compressor temperatures. It also
protects the compressor from overheating, due to im-
proper cooling from hot suction gas, high water tempera-
tures, or high discharge pressures.

The compressor will shut down whenever the sump tem-
perature exceeds 180°F (82.2°C) for the first minute of
operation or 160°F (71.1°C) after one minute of opera-
tion.

An example of the Oil Temp Inhibit safety display is
shown below:

MANUAL RESET SAFETIES (1 Fault and Lockout)

A Manual Reset Safety will shut the affected system
down and lock it out whenever the safety threshold is
exceeded.

After a system has shut down and locked out, a fault
display indicating the last system fault will appear on
the STATUS display message. This is accessible by
pressing the STATUS key.

To reset a locked out system, turn the affected system
switch on the Microprocessor Board (Page 74) to the
OFF position.

CAUTION: Before returning a locked out system to

service, a thorough investigation of the cause
of the fault should be made. Failure to re-
pair the cause of the fault while manually
allowing repetitive restarts may cause fur-
ther expensive damage to the system.

Each of the Manual Reset Safeties will be discussed in
detail below.

High Motor Current Safety

The High Motor Current Safety assures that motor life is
not diminished due to operating beyond the current rat-
ing of the motor. The Micro begins monitoring motor cur-
rent after 3 seconds of operation. If motor current ex-
ceeds 120% FLA after 3 seconds of operation, the com-
pressor will shut down. After 4 seconds of operation,
motor current must be less than 115% FLA as long as
the compressor continues to run.

An example of the High Motor Current display is shown
below:

S Y S # 1

H I G H

O I L

T E M P

S Y S # 2

H I G H

O I L

T E M P

S Y S # 1

H I G H

M T R