34
3. Reconnect wires to terminals LTB1-11 and LTB1-12. Mea-
sure voltage again between LTB1-11 and LTB1-12, volt-
age should flash high and low every 0.5 seconds. The
voltage on the low end will measure about 19 VDC, while
the voltage on the high end will measure from approxi-
mately 24 to 38 VDC.
4. Verify all modes of operation, by running the unit through
all of the steps in the “Test Modes” section discussed in
“Unit Start-Up”.
5. After verifying proper unit operation, exit the test mode.
Turn the fan on continuously at the ZSM, by pressing the
button with the fan symbol. If the fan comes on and runs
continuously, the ZSM is good. If you are not able to turn
the fan on, the ZSM is defective.
Unit Control Processor (UCP) Default Chart
If the UCP loses input from the building management
system, the UCP will control in the default mode after
approximately 15 minutes. If the UCP loses the Heating and
Cooling setpoint input, the UCP will control in the default
mode instantaneously. The temperature sensing thermistor
in the Zone Sensor Module is the only component required
for the “Default Mode” to operate.
System Defaults
Component or Function
Default Operation
Cooling Setpoint (CSP)
74 F
Heating Setpoint (HSP)
71 F
Economizer Normal
Operation
Economizer Minimum
Normal Operation
Position
Normal operation, or auto if
Mode
ZSM mode switch has failed
Normal operation, or
Fan
continuous if fan mode
switch on ZSM has failed
Disabled - Used with
Night Setback Mode
Integrated Comfort™ System
Programmable ZSM’s only
Disabled - Used with
Supply Air Tempering
Integrated Comfort™ Systems
Unit Control Processor (UCP) Switch Setting Table
In some Constant Volume (CV) applications, it may be
desirable to increase or decrease the heating anticipation in
the zone control algorithm to minimize temperature swings in
the space. This can be done by setting the switches on the
UCP per the following table.
Unit Control Processor (UCP) Switch Settings
Switch Switch
Heat
1
2
Anticipation
Off
Off
Normal (Default)
Off
On
Shorter
On
Off
Longer
On
On
Special
Trouble Shooting
Note: The Special setting is used when a very short
heating cycle is required, typically used when the
equipment heat capacity is over sized for the
application, will alleviate temperature swings.
Unit Operation without a Zone Sensor
This procedure is for temporary operation only. The
economizer and condenser fan cycling functions are
disabled.
1. Open and Lock the unit disconnect Switch.
2. Remove the Outside Air Sensor (OAS) from the return air
section of unit.
3. Use two (2) wire nuts, to individually cap the wires.
4. Locate the Low Voltage Terminal Board (LTB1) on the
right side of the control box. Connect two (2) wires to ter-
minals LTB1-1 and 2.
5. Connect the sensor (OAS) using two wire nuts to the two
(2) field supplied wires that were connected to terminals 1
and 2 on LTB1.
Unit Economizer Module (UEM) Test
Procedures
This series of tests will allow you to diagnose, and determine
where, and if a problem exists in the system economizer
operation. Test 1 determines if the problem is in the UCP, or
if it is in the UEM or ECA. Test 2 will determine if the
problem is in the UEM or the ECA. Test 3 is for the UEM’s
minimum position potentiometer. Test 4 tests sensor and
exhaust fan outputs. Test 5 shows how to test the sensors.
Conduct the tests in numerical order until problem is found.
Test 1
Verifying communication between the UCP and the UEM
1. Using the “Test Mode” described in the “System Start-Up”
section, Step the unit into the economizer mode and verify
that the economizer actuator (ECA) drives fully open (ap-
proximately 90 seconds). The LED on the UEM glows
continuously when the ECA drives.
2. If the ECA is not driving the dampers in Step 1, measure
the DC voltage output from the UCP. This is measured be-
tween terminals J1-11 and J5-5 on the UEM. The voltage
measured while the ECA is driving open should be ap-
proximately 1.7 VDC. When the 90 seconds have
elapsed, and the dampers should be fully open, the volt-
age will change to approximately 5 VDC.
3. Step the unit into the Cool 1 mode, the ECA should drive
fully closed (approximately 90 seconds), and then open to
the preset minimum position. The LED on the UEM glows
continuously when the ECA drives.
