Trane Precedent THC036E, Руководство по установке и обслуживанию

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Troubleshooting
RT-SVX22J-EN 57
Electro Mechanical Control
To prevent injury or death from electrocution, it is the
responsibility of the technician to recognize this hazard
and use extreme care when performing service
procedures with the electrical power energized.
Cooling Failure
1. Cooling and heating set point (slide pot) on the
thermostat has failed.
2. CC1 or CC2 24 VAC control circuit has opened, check
CC1 & CC2 coils, and any of the controls below that
apply to the unit (HPC1, HPC2, LPC1, LPC2, Frostat™).
Resetting Cooling and Heating Lockouts
Cooling Failures and Heating Lockouts are reset in an
identical manner. Method 1 explains resetting the system
from the space; Method 2 explains resetting the system at
the unit.
Method 1
To reset the system from the space, turn the “Mode”
selection switch at the thermostat to the “Off” position.
After approximately 30 seconds, turn the “Mode”
selection switch to the desired mode, i.e. Heat, Cool or
Auto.
Method 2
To reset the system at the unit, cycle the unit power by
turning the disconnect switch “Off” and then “On”.
Unit Economizer Control (ECA)
Test Procedures
Electro Mechanical Control
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 Unit, or if it is in the ECA. Test 2 tests sensor inputs.
Test 3 tests the resistors and sensors. Conduct the tests in
numerical order until problem is found.
Test 1
Verifying that the economizer actuator (ECA) is functional:
1. Using the “Test Mode” described in the “System Start-
Up” section, put the unit into the economizer mode
and verify that the economizer actuator (ECA) drives
fully open (approximately 90 seconds).
2. If the ECA is not driving the dampers, verify that 24 VAC
is between the ECA terminals TR and TR1 is present. If
24 volts is not present, a wiring or terminal problem
exists from the control transformer. Make any
necessary repairs, see wiring diagrams to
troubleshoot.
3. If 24 VAC is present, adjust the minimum position
potentiometer fully clockwise. If the actuator does not
drive, the economizer actuator is bad. Replace the ECA.
Test 2
Testing the ECA resistors and sensors
1. Testing the Mixed Air Sensor (MAS). Disconnect the
wires connected to T and T1 on the ECA, and;
a. Measure the resistance of the sensor between the
wires 180B and 181B.
b. Measure the temperature at the MAS location.
Using the Temperature versus Resistance chart,
verify the accuracy of the MAS.
Replace the sensor if it is out of range.
2. Testing the Outdoor Air Switch. If the temperature is
above 60 degrees, it will need to be chilled. Measure
the resistance of the sensor on the ECA SO and +.
The resistance should be approximately 390 Ohms.
Replace the Switch if it is open.
Replace the ECA if it is out of range.
3. Testing the R1 Resistance.
Measure the resistance of the sensor on the ECA SR
and +.
The resistance should be approximately 420 Ohms.
Replace the ECA if it is out of range.
4. Testing the R2 Resistance.
Measure the resistance of the sensor on the ECA P and
P1.
The resistance should be approximately 130 Ohms.
Replace the ECA if it is out of range.
Troubleshooting procedures for
Direct Drive Plenum Fan
Prior to troubleshooting, verify all wiring and wiring
connections. The motor has internal protections that will
shut down the motor before damage occurs. A power
cycle is required to reset some of the internal protections.
Before proceeding, power down unit for 1 minute and then
power on.
WARNING
Live Electrical Components!
During installation, testing, servicing and
troubleshooting of this product, it may be necessary to
work with live electrical components. Have a qualified
licensed electrician or other individual who has been
properly trained in handling live electrical components
perform these tasks. Failure to follow all electrical
safety precautions when exposed to live electrical
components could result in death or serious injury.