Carrier 16DF013-050 - Manual (Page 30)

Table 10 — Abnormal Shutdown Conditions
AUTO. LIMIT LIMIT CONTROL STOP LOW
DILUTION
CONDITION SETTING SYMBOL CODE FIRE
Low leaving chilled water temperature cutout (cooling only) 4 C (39 F) 26CW E01 No Yes
High-temperature generator high-solution temperature
switch
170 C (338 F) T4H E05 No Yes
High-temperature generator high-pressure switch -20 mm Hg (-.8 in.) 63GE E05 No Yes
Exhaust gas high-temperature switch 300 C (572 F) 26EH E06 No Yes
Fire tube high-temperature switch 300 C (572 F) 26TH E06 No Yes
Burner combustion failure/limit
• Within 3 minutes of machine start
• After 3 minutes of machine start Per device 86X
• E08
• E09
No Yes
External emergency limit switch Per device SE E10 No Yes
Refractory high-temperature switch 150 C (302 F) 26CA E06 No Yes
Solution pump motor overloads Rated amp 51SP E04 Yes No
Solution pump motor high-temperature switch 135 C (275 F) 26SP E04 Yes No
Refrigerant pump motor overloads (cooling only) Rated amp 51RP E04 Yes Yes
Refrigerant pump motor high-temperature switch
(larger size chillers, cooling only)
135 C (275 F) 26RP E04 Yes Yes
High-absorber; weak solution temperature sensor
(cooling only)
45 C (113 F) T2 E07 Yes Yes
Chilled/hot water low flow 50% design 69CW1 E02 Yes Yes
Cooling water low flow (optional) (cooling only) 50% design 69CW2 E03 Yes Yes
Chilled/hot water pump interlock Open circuit 88EP E02 Yes Yes
Cooling water pump interlock (cooling only) Open circuit 88CP E03 Yes Yes
Sensor error (7 conditions) Out of range — E13-34 Yes Yes
Operating Limit Controls — Several special fea-
tures allow the machine to continue to run in limited opera-
tion with certain abnormal conditions, until those conditions
either are corrected to resume normal operation or deterio-
rate to a point where the machine is automatically shut down:
HIGH-TEMPERATURE GENERATOR, HIGH SOLU-
TION LEVEL — An immersion electrode with a switched
output continuously monitors the high-stage generator so-
lution level. If a problem causes a high level and the con-
dition continues for 5 minutes, the solution pump is turned
off to stop solution supply to the generators. If the tempera-
ture of the solution leaving the high-stage generator is below
212 F (100 C) the solution pump is restarted after 60 sec-
onds. If the solution temperature is 212 F (100 C) or higher,
the pump is restarted after 30 seconds.
If the high level continues for 10 minutes, meaning it was
not corrected by stopping the pump, the alarm buzzer will
sound, the status indicator will display safety shutdown code
E13 for ‘‘electrode fault’’, and the machine will shut down
with the normal dilution cycle. The solution pump will con-
tinue operating through the shutdown sequence.
HIGH-TEMPERATURE GENERATOR, HIGH LEAVING
SOLUTION TEMPERATURE — When this temperature
reaches 311 F (155 C), the capacity control signal to the burner
is limited to prevent an increase in the heat input. If the tem-
perature continues to rise, a ‘‘close’’ signal is given to the
burner control for 2 or 3 seconds for each incremental in-
crease of 0.5° F (0.3° C).
If this temperature rises above 329 F (165 C), the close
signal is given in increments for 5 seconds. If the tempera-
ture continues to rise to 338 F (170 C), the burner will be
stopped immediately, the alarm buzzer will sound, the status
indicator will display safety shutdown code E05 for ‘‘high
strong solution temperature’’, and the machine will shut down
with the normal dilution cycle.
HIGH-TEMPERATURE GENERATOR, HIGH-
SATURATION (VAPOR) TEMPERATURE — When this
temperature reaches 199 F (93 C), the capacity control sig-
nal to the burner is limited to prevent an increase in the heat
input. If the temperature continues to rise, a ‘‘close’’ signal
is given to the burner control for 2 or 3 seconds for each
incremental increase of 0.4° F (0.3° C). If this temperature
rises above 203 F (95 C), the close signal is given in incre-
ments for 5 seconds.
CONCENTRATION CONTROL VALVE — When the tem-
perature of the solution leaving the absorber drops below 91
F (33 C) during cooling operation, because of low cooling
water temperatures, the concentration control valve is opened.
This valve is located in a condensate line between the bot-
tom of the condenser and the evaporator and, when open,
drains extra refrigerant into the evaporator. This is to pre-
vent possible refrigerant pump cavitation and damage due to
loss of refrigerant with the low solution concentrations which
can occur with cooling water temperatures below design. The
valve closes when the solution temperature rises above 95 F
(35 C).
The concentration control valve is also opened during the
shutdown dilution cycle and during heating operation.
COOLING TOWER CONTROL — When the temperature
of the solution leaving the absorber drops below 77 F
(25 C) during cooling operation, because of low cooling wa-
ter temperatures, the tower fan is turned off. When the so-
lution warms to 86 F (30 C), the fan is turned back on.
If the solution temperature rises to 113 F (45 C), because
of very high cooling water temperatures or poor heat trans-
fer, the alarm buzzer will sound, the status indicator will dis-
play E07 for ‘‘high weak solution temperature’’, and the ma-
chine will shut down with the normal dilution cycle.
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