Johnson Controls York YCAL0014E Series, Installation, Operation & Maintenance Instructions Manual

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JOHNSON CONTROLS
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FORM 150.62-NM6 (103)
EvAPORATOR PUMP START CONTACTS
Terminal block CTb2 – terminals 23 to 24, are nor mally-
open contacts that can be used to switch field supplied
power to provide a start signal to the evapo rator pump
contactor. The contacts will be closed when any of the
following conditions occur:
1. Low Leaving Chilled Liquid Fault
2. Any compressor is running
3. Daily schedule is not programmed OFF and the
Unit Switch is ON
The pump will not run if the micro panel has been pow-
ered up for less than 30 seconds, or if the pump has
run in the last 30 seconds, to prevent pump motor over-
heating. Refer to Figure 6 and unit wiring dia gram.
SYSTEM RUN CONTACTS
Contacts are available to monitor system status. Nor-
mally-open auxiliary contacts from each com pressor
contactor are wired in parallel with CTb2 – terminals
25 to 26 for system 1, and CTb2 – termi nals 27 to 28
for system 2 (YCAL0040 - YCAL0124). Refer to Figure
6 and unit wiring diagram.
ALARM STATUS CONTACTS
Normally-open contacts are available for each re frigerant
system. These normally-open contacts close when the
system is functioning normally. The respective contacts
will open when the unit is shut down on a unit fault, or
locked out on a system fault. Field connections are at
CTb2 terminals 29 to 30 (system 1), and terminals 31
to 32 (system 2 YCAL0040 - YCAL0124).
REMOTE START/STOP CONTACTS
To remotely start and stop the chiller, dry contacts can be
wired in series with the flow switch and CTB1 - termi nals
13 to 14. Refer to Figure 6 and unit wiring diagram.
REMOTE EMERGENCY CUTOFF
Immediate shutdown of the chiller can be accomplished
by opening a field-installed dry contact to break the elec-
trical circuit between terminals 5 to L on terminal block
CTb2. The unit is shipped with a factory jumper installed
between terminals 5 to L, which must be removed if
emergency shutdown contacts are installed. Refer to
Figure 6 and unit wiring diagram.
PwM INPUT
The PWM input allows reset of the chilled liquid set-
point by supplying a “timed” contact closure. Field wiring
should be connected to CTb1 – terminals 13 to 20. A
detailed explanation is provided in the Unit Control sec-
tion. Refer to Figure 6 and unit wiring diagram.
LOAD LIMIT INPUT
Load limiting is a feature that prevents the unit from
loading beyond a desired value. The unit can be “load
limited” either 33%, 40%, 50%, 66% or 80%, depending
on the number of compressors on unit. The field con
-
nections are wired to CTb1 – terminals 13 to 21, and
work in conjunction with the PWM inputs. A detailed
explanation is provided in the Unit Control section. Refer
to Figure 6 and unit wiring diagram.
When using the Load Limit feature,
the PWM feature will not function
– SIMULTANEOUS OPERATION
OF LOAD LIMITING AND TEM­
PERATURE RESET (PWM INPUT)
CANNOT BE DONE.
FLOw SwITCH INPUT
The flow switch is field wired to CTB1 terminals 13 - 14.
See Figure 6 and unit wiring diagram.
COMPRESSOR HEATERS
Compressor heaters are standard. If power is OFF more
than two hours, the crankcase heaters must be ener-
gized for 18 - 24 hours prior to restarting a compressor.
This will assure that liquid slugging and oil dilution does
not damage the compressors on start.
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