Trane Voyager RT-SVX17C-EN Installation Operation & Maintenance page 72

SYMPTOM
Q. Economizer will not 1. Economizer connector not
operate.
2. Economizer Actuator
3. Wiring or terminal failure.
4. ECA is defective.
R. Minimum position 1. Remote Minimum position
is at zero, cannot
be adjusted. Economizer
2. Minimum position
still modulates.
S. Economizer goes to 1. OAS has failed.
minimum position,
and will not modulate. 2. MAS has failed.
T. Economizer modulates, 1. Comparative enthalpy setup, 1. Check the return air sensor (RAS) at connector P10 by disconnecting
but system does not
seem to operate as
effeciently as in the past.
2. Referance enthalpy setup,
3. Comparative enthalpy setup, 3. Perform #2 above.
U. Power Exhaust will 1. Exhaust motor has failed.
not operate. 2. XFR has failed.
3. ECA has failed.
4. XFSP has Failed
V. IGV/ VFD will not 1. RTAM has Failed
operate properly 2. IGV / VFD has Failure
3. Setpoint Failure
PROBABLE CAUSE
plugged into unit wiring
harness
(ECA) has failed
potentiometer has failed.
potentiometer has failed.
RAS or RHS failed.
System is operating using
Referance enthalpy
OHS has failed.
System is operating using
dry bulb control.
OHS has failed.
System is operating using
dry bulb control.
System Troubleshooting Chart (Continued)
RECOMMENDED ACTION
1. Check connector, and connect if necessary.
2. Verify that 24 VAC is present between ECA terminals 24 VAC and Common.
Place the unit in econ test mode, economizer actuator should drive open.
In any other unit test mode, economizer actuator should drive to minimum
position. If ECA does not drive as specified, replace ECA.
3. Check wiring and terminals. Repair or replace if necessary.
4. Perform the ECA Test Procedures discussed previously.
1. With the main power off, check the resistance between terminals P
and P1 at the ECA by rotating the remote minimum position
potentiometer knob. Resistance should be 50 to 200 Ohms.
2. Rotate the onboard minimum position potentiometer knob.
If ECA does not drive to different minimum position, replace ECA.
1. Check the OAS at connector P8 by disconnecting P8 from J8 on the
RTRM. Check resistance between P8-1 and P8-2, refer to the
Resistance versus Temperature Chart. Replace sensor if necessary.
2. Check the MAS at connector P23 by disconnecting P23 from MAT on
the ECA. "MAT" is marked on the actuator. Check for
resistance between P23-1 and P23-2, refer to the Resistance versus
Temperature Chart. Replace sensor if necessary.
P10 from RAT on the ECA.
Check for resistance between P10-1 and P10-2, refer to the
Resistance versus Temperature Chart. Replace the sensor
if necessary.
Check the return air humidity sensor (RHS) by measuring the
operating current at terminals RAH-1 and RAH-2 on the ECA.
Normal operating current is 4 to 20 milliamps mA.
Note: The humidity sensors are polarity sensitive, and will not operate
if connected backwards.
2. Check the outside humidity sensor (OHS) by measuring the opeating
current at terminals OAH-1, and OAH-2 on the ECA. Normal
operating current is 4 to 20 milliamps mA.
1. Check the exhaust fan motor, and replace if necessary.
2. Check the exhaust fan contactor (XFR). Replace if necessary
3. Perform the ECA Test Procedures discussed previously.
4. Perform the Exhaust Fan Setpoint Test Procedures discussed
previously.
1. Perform the RTAM Test Procedures discussed previously.
2. Check the IGV / VFD
3. Perform the IGV / VFD Setpoint Test Procedures discussed
previously.
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