York Millennium YCAS 316 Installation Operation & Maintenance page 77

System 1
Pressures / Temperatures
Oil pressure, suction pressure, discharge pressure,
suction temperature*, discharge temperature, oil tem-
perature, saturated discharge temperature, saturated
suction temperature, slide valve position and superheat
on System 1 will be displayed when this key is repetitively
pressed. The key must be pressed 6 times to scroll
through the 6 displays required to display these operating
parameters.
Temperatures and pressures may be measured directly
by transducers and temperature sensors. Others are
computed from these measurements:
• Differential oil pressure is measured by subtracting oil
pressure measured by a transducer located in the oil
line after the oil filter from the discharge pressure. (Oil
in the oil separator is at discharge pressure.)
Ideally, oil injected after the filter, is at discharge
pressure. This makes ideal differential oil pressure 0
PSID. However, a pressure drop occurs across the oil
filter. Typically, the drop will be 0 - 10 PSID. As the filter
becomes clogged, oil pressure will eventually rise
above 40 PSID.
• Saturated Discharge Temperature is computed by
converting discharge pressure to temperature.
• Saturated Suction Temperature is computed by
converting suction pressure to temperature.
• Slide Valve Position is computed internally by an
algorithm in the micro based on average % FLA motor
current, programmed motor current equal to 100%
FLA, actual condensing temperature, programmed
condensing temperature for a particular chiller model,
and the number of load pulses sent by the micro.
NOTE: Slide valve position is approximate and should
be used for reference only.
• Superheat is computed by subtracting saturated suc-
tion temperature from suction temperature.
Shown below are the 6 pressure / temperature displays:
S Y S 1 O I L =
S P = 5 5 D P =
S Y S 1 S U C
D S C H
O I L T E M P 1
S A T D I S H 1
S A T S U C T 1
YORK INTERNATIONAL
SYSTEM 1
PRESS / TEMP
5 0 P S I D
2 4 8 P S I G
= 3 6 . 2 ° F
= 1 2 1 . 2 ° F
= 7 7 . 9 ° F
= 1 3 0 . 0 ° F
= 2 4 . 3 ° F
S Y S 1 S L I D E
P O S I T I O N
S Y S # 1 S U P E R H E A T
Minimum and maximum limits or values on the displays
are shown below. When a minimum limit or value is
exceeded, a " < " sign will appear before the numerical
value. In the case of maximum limits or values,
exceeding them will cause a " > " sign to appear.
NOTE: Minimum and maximum values may change as
software (EPROM) revisions are made.
MIN. LIMITS
OIL PRESSURE 208 PSID
SUCTION PRESSURE 0 PSIG (O BAR G) 199 PSIG (13.7 BAR G)
DISCHG. PRESSURE 0 PSIG (O BAR G) 399 PSIG (27.5 BAR G)
SUCTION TEMP. *9.0°F (-12.8°C)
DISCHARGE TEMP. 40.3°F (4.6°C)
OIL TEMP. 40.3°F (4.6°C)
SAT. DISCHG. TEMP. -41.0°F (-40.6°C)
SAT. SUCTION TEMP. -41.0°F (-40.6°C)
SLIDE VALVE POS
SUPERHEAT *-81.5°F (-63.1°C)
* NOTE: Below 9.0°F (-12.8°C), the Suction Temp. display will
disappear. This will in turn cause the Superheat display to
disappear.
System 2
Pressures / Temperature
Oil pressure, suction pressure, discharge pressure,
suction temperature**, discharge temperature, oil
temperature, saturated discharge temperature, saturated
suction temperature, slide valve position, and superheat
on system 2 will be displayed when this key is pressed.
The key must be pressed 6 times to scroll through the 6
displays required to display these operating parameters.
Temperatures and pressures may be measured directly
by transducers and temperature sensors. Others are
computed from these measurements:
• Differential oil pressure is measured by a subtracting
oil pressure measured by a transducer located in the oil
line after the filter, from the discharge pressure. (Oil in
the oil separator is at discharge pressure.)
Ideally, oil injected after the filter, is at discharge
pressure. This makes ideal differential oil pressure 0
PSID. However, a pressure drop occurs across the oil
filter. Typically, the drop will be 0 - 10 PSID. As the filter
becomes clogged, oil pressure will eventually rise
above 40 PSID.
• Saturated Discharge Temperature is computed by
converting discharge pressure to temperature.
FORM 201.10-NM1
V A L V E
= 1 0 0 %
= 1 2 . 2 ° F
MAX. LIMITS
0 PSID (O BARD)
84.2°F (29.0°C)
302.6°F (150.3°C)
240.0°F (115.6°C)
140.5°F (60.3°C)
101.3°F (38.5°C)
0% 100%
60.9°F (16.1°C)
SYSTEM 2
PRESS/TEMP
77