JOHNSON CONTROLS
34
FORM 150.67-NM2
ISSUE DATE: 01/31/2019
SECTION 4 – INSTALLATION
num wiring is not recommended due to thermal char-
acteristics that may cause loose terminations result-
ing from the contraction and expansion of the wiring.
Aluminum oxide may also build up at the termination
causing hot spots and eventual failure. If aluminum
wiring is used to supply power to the chiller, AL-CU
compression fittings should be used to transition from
aluminum to copper. This transition should be done in
an external box separate to the power panel. Copper
conductors can then be run from the box to the chiller.
A 120-1-60, 15 amp source must be supplied for the
control panel through a fused disconnect when a con-
trol panel transformer (optional) is not provided (Refer
to Figure 7 on page 36).
See unit wiring diagrams for field and power wiring
connections, chilled water pump starter contacts, alarm
contacts, compressor run status contacts, PWM input,
and load limit input. Refer to section on SECTION 8 –
UNIT OPERATION for a detailed description of opera-
tion concerning aforementioned contacts and inputs.
Evaporator Pump Start Contacts
Terminal block TB1 – 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
powered up for less than 30 seconds, or if the pump
has run in the last 30 seconds, to prevent pump motor
overheating. Refer to Figure 8 on page 37 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 TB1 – terminals 25
to 26 for system 1, and TB1 – termi nals 27 to 28 for
system 2 (YCAL0043 - YCAL0066). Refer to Figure
4 on page 23, Figure 8 on page 37 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 respec-
tive contacts will open when the unit is shut down on
a unit fault, or locked out on a system fault. Field con-
nections are at TB1 terminals 29 to 30 (system 1), and
terminals 31 to 32 (system 2 YCAL0043 - YCAL0066).
Remote Start/Stop Contacts
To remotely start and stop the chiller, dry contacts can
be wired to CTB1 terminals 13 to 51. Refer to Figure 4
on page 23, Figure 7 on page 36, and unit wiring
diagram.
Remote Emergency Cutoff
Immediate shutdown of the chiller can be accom-
plished by opening a field-installed dry contact to
break the elec trical circuit between terminals 5 to L
on terminal block TB1. The unit is shipped with a fac-
tory jumper installed between terminals 5 to L, which
must be removed if emergency shutdown contacts are
installed. Refer to Figure 8 on page 37 and unit wir-
ing diagram.
Remote Temp Reset Input
The Remote Temp Reset input allows reset of the
chilled liquid set point by supplying a voltage or cur-
rent signal field wiring should be connected to CTB1 –
terminals A+ to A-. A detailed explanation is provided
in the Unit Control section. Refer to Figure 2 on page
21 and Figure 4 on page 23 and unit wiring dia-
gram.
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%, depend-
ing on the number of compressors on unit. The field
connections are wired to CTB1 – terminals 13 to 21,
and work in conjunction with the PWM inputs. A de-
tailed explanation is provided in the Unit Control sec-
tion. Refer to Figure 4 on page 23, Figure 8 on page
37 and unit wiring diagram.
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