Carrier 30HR Product Data page 34

Guide specifications — 30HR (cont)
F. Controls, Safeties and Diagnostics:
1. Controls:
a. Unit controls shall include the following mini-
mum components:
1) Microprocessor.
2) Power and control circuit terminal blocks.
3) RUN/STANDBY control power switch.
4) Replaceable solid-state relay panel and
electronic expansion valve control.
5) Control panel with keypad and display
module.
6) Thermistors.
7) External communication port.
b. Capable of
functions:
1) Pumpout at beginning and end of every
circuit cycle.
2) Return temperature reset based on return
cooler fluid temperature outdoor-air tem-
perature, space temperature, or 4-20 mA
signal.
3) Scheduling of circulating pump and chiller
operation for occupied/unoccupied periods.
4) Capacity control based on leaving chilled
fluid temperature and compensated by rate
of change of return fluid temperature.
5) Limit the chilled fluid temperature pull-
down rate at start-up to 1° F (.56° C) per
minute to prevent excessive demand spikes
(charges) at start-up.
6) Automatic lead/lag control of refrigerant
circuits.
7) Two-stage demand limiting from remote
signal.
8) Remote alarm activation.
2. Safeties:
a. Unit shall be equipped with thermistors and
all necessary components in conjunction with
the control system to provide the unit with
the following protections:
1) Loss of refrigerant charge protection.
2) Low fluid flow protection.
3) Low chilled fluid temperature protection.
4) Low and high superheat protection.
5) Low oil protection for each compressor
circuit.
6) Low control voltage (to unit) protection.
b. Compressors shall be equipped with the fol-
lowing manual reset type protections:
1) Thermal overload.
2) Pressure overload.
34
performing the following
3) Electrical overload through the use of con-
tactors and calibrated, ambient compen-
sated, magnetic trip circuit breakers. Cir-
cuit breakers shall open all 3 phases in the
event of either an overload in any one
phase, or a single-phasing condition.
3. Diagnostics:
a. Diagnostic display module shall be capable of
indicating the safety lockout condition by dis-
playing a code for which an explanation may
be scrolled at the display. Protections included
for display shall be:
1) Compressor lockout.
2) Loss of charge.
3) Low fluid flow.
4) Low oil pressure.
5) Cooler freeze protection.
6) High or low suction superheat.
7) Thermistor malfunction.
b. Unit control must also be capable of perform-
ing a run test to verify operation of every
switch, thermistor, solenoid valve, unloader,
and compressor before chiller is started.
G. Electrical Requirements:
1. Control voltage shall be 115-v, single-phase, sepa-
rate power supply.
2. Unit shall be shipped with factory control and
power wiring installed.
3. Each primary electrical power supply shall be con-
nected at a single location.
H. Special Features:
Certain standard features are not applicable when the
features designated by * are specified.
* 1. Condenser manifold package (070-140), field welded.
* 2. Control circuit transformer (115 v), field installed.
* 3. Remote reset thermistor, field installed.
4. Unit sound enclosure panels, field installed.
5. Suction and discharge pressure gages with valves,
field installed.
* 6. Oil-pressure safety switch, field installed.
* 7. Leaving chilled fluid temperature reset. LCWT shall
be reset from occupied space, outdoor air, or re-
turn fluid temperature.
* 8. Demand limit control. Unit shall be equipped with
a 2-point demand limit control (0-49% and 50-
100%) actuated remotely by an electronic signal.
9. Chilled fluid flow switch, field installed.