HVAC Cooling Monitor

Peripheral Specification
Part #150858
HVAC Cooling Monitor
Overview
The Quest HVAC Cooling Monitor is designed to monitor the
supply air temperature of an HVAC system and provide an
alarm contact when the cooling is not operating properly.
This acts as an early indication that the air conditioner will
not support the temperature requirements of the building.
The device is simple to install and will work with any air
conditioning system.
Installation
The Cooling Monitor can be mounted in the low voltage
control section of the HVAC unit or in a double gang box near
the unit. The basic connections are 24 VAC power, cooling run
signal, supply air temperature and alarm output connection.
•Connect the R terminal to the available 24 VAC R
(or Hot) terminal in the AC unit or at the T-stat.
•Connect the C terminal to the 24 VAC Common (C)
terminal in the AC unit or at the T-stat.
•Connect the Cooling enable terminal (Y) from
the AC Unit to the Y/CT terminal of the Cooling
Monitor.
•Optional - instead of using a cooling enable
signal you can connect a current switch to the
AC compressor to provide a contact closure when
the compressor is on. Connect the current switch
to the Cooling monitor at terminals Y/CT and CTV.
•Install the included supply air sensor to monitor
the temperature of the air coming out of the AC
unit. Connect the two leads to the Therm + and
Therm – terminals on the Cooling Monitor. These
connections are not polarity sensitive.
•Connect the alarm output from the cooling
monitor to your Quest monitoring system. The
contacts are normally closed and will open on
alarm, temperature sensor failure or
power failure.
Specifications
Part Number: 150858
Connectors: Two-piece pluggable connector for HVAC,
thermistor, and alarm wiring
Alarm Status: LEDs for power and alarm/status
Configuration using DIP Switches
The cooling monitor provides an eight position DIP switch
(SW2) for configuration of setpoint, hysteresis and time values.
The switches are labeled 1-8 and read left to right looking
directly at the board with the terminal block to the left edge of
the board. The switch positions are:
Switches 1-3: Alarm Temperature Threshold (degrees F)
Switches 4-5: Alarm Hysteresis Temperature (degrees F)
Switches 6-7: Initial Call for Cooling Wait (minutes)
Switch 8: Delay before Alarm (minutes)
Detail of board (left). HVAC Cooling Monitor
board in enclosure (part #150858) shown with
Supply Air Temperature Thermistor Sensor
(part #300199) included.
Once you set the switches appropriately for your installation,
you must reset or power cycle the device to have the settings
take effect.
Configuration using DIP Switches (factory default settings shown in white text)
Switch
2
OFF
OFF
ON
ON
OFF
OFF
ON
ON
1
OFF
OFF
OFF
OFF
ON
ON
ON
ON
3
OFF
ON
OFF
ON
OFF
ON
OFF
ON
Temp.
(°F)
57
59
61
63
65
67
69
71
Switch
4
OFF
OFF
ON
ON
-
Hysteresis
(°F)
1
2
3
4
-
5
OFF
ON
OFF
ON
-
Start up
On power up, the green power LED (labeled PWR) will be on
and the Cooling Monitor will go through a diagnostic check to
ensure it is operating properly. The red status LED (labeled STA)
will blink four times and then enter normal operating mode if
it passes its internal diagnostics. The status LED will be on solid
and the alarm contacts will be open (alarm) if the board fails
initial startup. Replace the Cooling Monitor if it fails the initial
startup diagnostics.
Normal Operation
After start up, the Cooling Monitor will constantly monitor the
call for cooling. When there is a call for cooling (24 VAC present
at Y/CT terminal) for the configured “Initial Call for Cooling
Wait” continuous minutes, the cooling monitor will transition
to the supply sensor monitor mode. In this mode, once the
Switch
6
OFF
OFF
ON
ON
-
7
OFF
ON
OFF
ON
-
Wait Switch Delay
(min.)
8
(min.)
10
OFF
5
15
ON
10
30
45
-
supply temperature is greater than the “Alarm Temperature
Threshold” plus the “Alarm Hysteresis Temperature” for
the “Delay before Alarm” continuous minutes, the cooling
monitor will go into Alarm mode (opens the alarm contact.)
If at any time the supply sensor dips under that setpoint
while counting the delay (before going into the Alarm
mode), the cooling monitor will transition back to the
beginning call for cooling mode (and the initial wait starts
over.) Once in Alarm mode, the cooling monitor must see
a supply temperature of less than “Alarm Temperature
Threshold” minus the “Alarm Hysteresis Temperature”
degrees AND the call for cooling must still be present before
it will transition out of Alarm mode and back into the
beginning call for cooling mode.
Alarm Notification: 1 output for system alarm. Contact
rated for 48VDC @ 100 mA
The Cooling Monitor has the following alarm capabilities
Inputs: One (1) thermistor input for monitoring cooling
temperature (10K Type III thermistor.) Also monitors Y Control
signal for call for cooling signal.
Green LED
Power (PWR)
RED LED
Status (STA)
Alarm Output
Problem
OFF
OFF
Open (in alarm)
ON
ON
Open (in alarm)
No power to the Cooling Monitor
Cooling running for initial wait and supply air temp > the alarm
temp threshold plus the alarm hysteresis temp for alarm delay
Programming: Factory configured using 65°F setpoint for
cooling detection (with 1°F of hysteresis each side.)
Power: 24 VAC @ 75 mA normal operation
Operating Range: -40 to 180°F (-40 to 82°C)
ON
Storage Temperature: -40 to 185°F (-40 to 85°C)
ON
Size (W x H x D) / weight: 4” x 4” x 1.5” (102 x 102 x 38 mm)
/ 1 lb (454 g), Thermistor Sensor: 4” x 9.7” x 2.6” (102 x 246 x
66 mm) / 0.5 lb. (227 g)
www.questcontrols.com
Tel: (941) 729-4799, Fax: (941) 729-5480
208 9th Street Drive West, Palmetto, Florida 34221
150858 HVAC 102313 V6 Specifications subject to change without notice
Blinks once per
second
OFF
Open (in alarm)
The supply air sensor has either an open or short on the wires
Closed (normal)
Air conditioner is operating properly