McQuay RCS User Manual

Page 18 IM-738
Controls, Settings, and Functions
Table 3 and Table 4 on page 19 present a listing of all the unit
control devices. Included in the table are the device symbol, a
description of the device, its function, and any reset informa-
tion, its location, any device setting, any setting ranges, differ-
entials, and the device part number.
Table 3: Controls, settings and functions
SYMBOL DESCRIPTION FUNCTION RESET LOCATION SETTING RANGE DIFFERENTIAL PART NO.
CS1 & 2 Switch (toggle),
refrigerant circuit
Shuts off compressor control
circuits manually.
N/A Condenser
control box
N/A N/A N/A 01355000
DAT Discharge air
temperature sensor
Senses discharge air
temperature.
N/A Discharge air
section
N/A 3K ohms at
77°F (25°C)
N/A 060004705
DHL Duct high limit
switch
Prevents excessive VAV duct
pressures; shuts off fan.
Auto Main control
panel
3.5” w.c (871.8 Pa) 0.05-5.0” w.c.
(12.5-1245.4 Pa)
.05" w.c.
(12.5 Pa), fixed
065493801
EFT Entering fan air
temperature sensor
Senses entering fan air
temperature
N/A Inlet of supply
fan
N/A 3K ohms
at 77°F (25°C)
N/A 060004705
FP1, 2 Evaporator frost
protection
N/A
FS1 Freezestat Shuts off fans, opens heating
valve and closes outdoor
damper if low air temperature
at coil is detected.
Auto Heating
section
38°F (3°C)
or as required
35°F - 45°F
(2°C - 7°C)
12°F (7°C), fixed 065830001
HP1, 2,
3 & 4
High Pressure
Control
Stops compressor when
refrigerant discharge pressure
is too high.
Manual
(relay
latched)
Compressor Cutout = 400 psig
(2758 kPa)
Cutin = 300 psig
(2068 kPa)
N/A 100psi
(689 kPa)
047356110
LP1, 2 Low Pressure
Control
Stops compressor when
suction pressure is too low
(used for pumpdown).
Auto Compressor Cutout=35 psig
(241 kPa)
Cutin=60 psig
(414 kPa)
N/A 25 psi
(172 kPa)
047356111
MCB Main Control Board Processes input information. N/A Main control
box
N/A N/A N/A 060006101
MP1, 2,
3 & 4
Compressor motor
protector
Senses motor winding
temperature, shuts off
compressor on high
temperature.
Notes:
1. Unit size 018C
compressors include
internal motor protector.
2. Unit sizes 020C - 036C,
circuit #1 compressors
include internal motor
protector (refer to unit
wiring diagram).
Auto at
3400
ohms
Compressor
junction box
9K-18K ohms 700 ohms cold N/A 044691509
OAE Enthalpy control
(electromechanical)
Returns outside air dampers
to minimum position when
enthalpy is too high.
Auto Economizer
section
"B" or as required A — D Temperature:
3.5°F (2°C)
Humidity:
5% fixed
030706702
Enthalpy control
(electronic)
Returns outside air dampers
to minimum position when
outside air enthalpy is higher
than return air empalthy
(use RAE)
Auto Economizer
section
Fully CW past "D"
(when used
with RAE)
A — D N/A 049262201
OAT Outside air
temperature sensor
Senses outside air
temperature.
N/A N/A 3K ohms at
77°F (25°C)
N/A 060004705
PC5 Dirty Filter switch Senses filter pressure drop. Auto First Filter
section
As required .05-5” w.c.
(12.5-1245.4 Pa)
.05” w.c.
(12.5 Pa)
065493801
PC6 Dirty Filter switch Senses filter pressure drop. Auto Final Filter
section
As required .05-5” w.c.
(12.5-1245.4 Pa)
.05” w.c.
(12.5 Pa)
065493801
PC7 Air flow proving
switch
Senses supply fan pressure
to prove airflow.
Auto Supply fan
section
.10" w.c. (25 Pa) .05-5” w.c.
(12.5-1245.4 Pa)
.05” w.c.
(12.5 Pa), fixed
060015801
PS1, 2 Pumpdown switch Used to manually pump down
compressor.
N/A Condenser
control box
N/A N/A N/A 01355000
PS3 Master pumpdown
switch
Used to manually pump down
all compressors.
N/A Main control
box
N/A N/A N/A 01355000

McQuay RCS Specifications

General

Brand	McQuay
Model	RCS
Category	Air Handlers
Language	English