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1.13 ANTI-RECYCLE TIMER
The programmable Anti-Recycle Timer allows the user
to select the compressor anti-recycle time to best suit
their needs. Motor heating is a result of inrush current
when the motor is started. This heat must be dissipated
before another start takes place or motor damage may
result. The anti-recycle timer assures that the motor
has sufficient time to cool before it is restarted.
An adjustable timer allows for the motor cooling, but
gives the user the ability to extend the anti-recycle timer
to cut down on cycling. In some applications, faster com-
pressor start response is necessary and shorter anti-
recycle times are required. These needs should be kept
in mind but, whenever possible, the timer should be ad-
justed for the longest period of time tolerable. 600 sec-
onds is recommended, although 300 seconds provides
adequate motor cooling time. Longer periods will allow
more heat dissipation, reduce cycling, and possibly in-
crease motor life. See Section 9 (8.2), page 145 for pro-
gramming of the anti-recycle timer.
1.14 ANTI-COINCIDENCE TIMER
The Anti-Coincidence Timer assures that 2 systems
do not start simultaneously. This assures that inrush
current is kept to a minimum. A 60-second time delay
will always separate motor starts. This timer is not
programmable.
1.15 EVAPORATOR PUMP CONTROL
Dry contacts (Terminals 25 and 26, see Fig. 9 for loca-
tion) are provided, which transition (close) when the
Daily Schedule is calling for chiller operation and power
has been applied to the micro panel for 30 seconds. If
for some reason the evaporator pump contacts have
been closed to run the pump and a power loss or Daily
Schedule shuts the pump down (contacts open), the
contacts will not reclose for any reason until 30 sec-
onds have elapsed after power re-application, or 30 sec-
onds have elapsed between a Daily Schedule shutdown
and restart.
The contacts will also close if a Low Water Temp Fault
occurs.
1.16 COMPRESSOR HEATER CONTROL
Each compressor has its own heater. The heater will be
off whenever the compressor is running.
YORK INTERNATIONAL
1.17 EVAPORATOR HEATER CONTROL
The evaporator heater is controlled by ambient tem-
perature. When the ambient temperature drops below
4°C (40°F), the heater is turned on when the compres-
sors are turned off. When the temperature rises above
7°C (45°F), the heater is turned off. An undervoltage
condition will keep the heater off until full voltage is
restored to the system. The heater will provide freeze
protection to -29°C (-20°F).
115VAC power must remain "ON"
through CB1 and CB3 for freeze pro-
tection. Otherwise, the evaporator
must be drained.
1.18 PUMPDOWN CONTROLS
Pumpdown control will pump down a system to the suc-
tion pressure cutout whenever the compressor shuts
down on a normal shutdown. Additionally, a recycling
pumpdown is employed on an as-needed basis to as-
sure that liquid does not accumulate in the evaporator
on an OFF system while cold chilled liquid is flowing
through the evaporator. Since pumpdown at startup is
not employed, the liquid line solenoid valve will open
immediately when a compressor starts.
"Pumpdown on shutdown" will pump a system down
whenever a system shuts down, except in two circum-
stances: a pumpdown will not occur whenever a fault
causes a shutdown, or when unit rocker switch is turned
"OFF". Pumpdown will continue until the suction pres-
sure falls below the suction pressure cutout. If the pres-
sure never drops below the cutout, pumpdown will con-
tinue until a three-minute pumpdown timer has expired.
During pumpdown, the following STATUS message will
be displayed:
S Y S # 1
P U M P I N G
S Y S # 2
P U M P I N G
The "Pumping Down" message indicates that the re-
spective compressor is unloaded, the liquid line solenoid
valve is closed, and is presently in the process of pump-
ing the system down. The compressor will either be in a
recycling pumpdown or in a pumpdown prior to shut-
down when this message is displayed. The message
will disappear when the compressor shuts off.
FORM 150.52-NM2 (1001)
D O W N
D O W N
9
111
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