Procedures; Economizer Fault Detection And Diagnostics; Verify Economizer Status By; Economizer Actuator - Trane Voyager Commercial Installation, Operation And Maintenance Manual

D D i i a a g g n n o o s s t t i i c c s s
Economizer Actuator (ECA/
RTEM) Test Procedures
Economizer Fault Detection and
Diagnostics
Fault Detection of the Outdoor Air Damper will be
evaluated based on the commanded position of the
damper actuator compared to the feedback position
from the damper actuator. The damper is commanded
to a position based on a 2-10 VDC signal. If the damper
position is outside of ±10% of the commanded
position, a diagnostic is generated.
N N o o t t e e : : Only one diagnostic will be active at any given
time.
Unit Not Economizing When it Should Be
The unit is operating in cooling mode, economizing is
enabled and/or mechanical cooling is enabled. If the
commanded economizer position is greater than the
current economizer feedback position +10% for 5
continuous minutes, a 'Unit Not Economizing When it
Should Be' diagnostic is generated.
Unit Economizing When it Should Not Be
The unit is operating in cooling mode, economizing is
enabled and/or mechanical cooling is enabled. If the
commanded economizer position is less than the
current economizer feedback position -10% for 5
continuous minutes, a 'Unit Economizing When it
Should Not Be' diagnostic is generated.
Outdoor Air Damper Not Modulating
If the unit is operating in ventilation only mode - not
attempting to economize - and the commanded
damper position is greater than the current damper
feedback position +10% for 5 continuous minutes, a
'Outside Air Damper Not Modulating' diagnostic is
generated.
Excessive Outdoor Air
If the unit is operating in ventilation only mode - not
attempting to economize - and the commanded
damper position is less than the current damper
feedback position -10% for 5 continuous minutes, a
'Excessive Outdoor Air' diagnostic is generated.
Mixed Air Temperature Low Limit Diagnostic
In all conditions on all ReliaTel controlled units, if the
Mixed Air Temperature falls below 45°F, the 'Mixed Air
Temperature Low Limit' diagnostic is active and the
economizer actuator will close to the active minimum
position. On Title 24 compliant units, ReliaTel will set
an Auto-Reset Diagnostic to be used by BAS and TD5
when the Mixed Air Temperature Low Limit is active.
The RTEM will revert to normal operation when the
Mixed Air Temperature rises above 48°F. The
134
Diagnostic will be reset when the Mixed Air
Temperature Low Limit is inactive.
Verify Economizer Status by Economizer
Actuator (ECA/RTEM)
LED indicator:
• OFF: No Power or Failure
• ON: Normal, OK to Economize
• Slow Flash: Normal, Not OK to Economize
• Fast Flash: ¼ Second ON/2 Seconds OFF
Communications Failure
• 1 Flash: Actuator Fault
• 2 Flashes: CO2 Sensor out of range
• 3 Flashes: RA Humidity Sensor out of range
• 4 Flashes: RA Temp Sensor out of range
• 6 Flashes: OA Humidity Sensor out of range
• 7 Flashes: OA Temp Sensor out of range
• 8 Flashes: MA Temp Sensor out of range
• 9-11 Flashes: Internal ECA failure
N N o o t t e e : : The Outdoor Air Sensor (OAS) is also used
for the economizer operation. It is connected
to the RTRM.
Test 1: Voltage
Disconnect the OAS from the wires in the return air
section. Check the voltage at the wires going to the
RTRM. The voltage should be 5 (± 0.25) Vdc.
Check the resistance at the wires going to the OAS and
measure the temperature at the OAS location. Using
the Temperature versus Resistance chart, verify the
accuracy of the OAS.
If voltage specified is not present, the ECA has failed.
Test 2: Testing the ECA sensors
1. Testing the Mixed Air Sensor (MAS). Disconnect the
cable connected to MAT on the ECA. Using the
Thermistor Resistance / Temperature Chart
a. Measure the resistance of the sensor between
the connector terminals P23-1 and P23-2.
b. Measure the temperature at the MAS location.
Using the Temperature versus Resistance chart,
verify the accuracy of the MAF.
Replace the sensor if it is out of range.
2. Testing the Return Air Sensor (RAS). Disconnect the
cable connected to RAT on the ECA. Using the
Thermistor Resistance / Temperature Chart
a. Measure the resistance of the sensor between
the connector terminals P10-1 and P10-2.
b. Measure the temperature at the RAS location.
Using the Temperature versus Resistance chart,
verify the accuracy of the RAS.
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