Troubleshooting - Trane TTA240F Series Installation Operation & Maintenance

Cooling Failure
1. Cooling and heating set point
(slide pot) on the zone sensor has
failed. Refer to the "Zone Sensor
Test Procedure" section.
2. Zone temperature thermistor
ZTEMP on ZTS failed. Refer to the
"Zone Sensor Test Procedure"
section.
3. 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).
4. LPC1 has opened during the 3
minute minimum "on time"
during 4 consecutive compressor
starts, check LPC1 or LPC2 by
testing voltage between the J1-8
& J3-2 terminals on the RTRM
and ground. If 24 VAC is present,
the LPCs have not tripped. If no
voltage is present, LPCs have
tripped.
Simultaneous Heat and Cool
Failure
1. Emergency Stop is activated.
Method 2
The second method for determining
system status is done by checking
voltage readings at the RTRM (J6).
The system indication descriptions
and the approximate voltages are
listed below.
System Failure
Measure the voltage between
terminals J6-9 & J6-6.
• Normal Operation =
approximately 32 VDC
• System Failure = less than 1 VDC,
approximately 0.75 VDC
• Test Mode = voltage alternates
between 32 VDC & 0.75 VDC
20

Troubleshooting

ReliaTel™ Controls
Heat Failure
Measure the voltage between
terminals J6-7 & J6-6.
• Heat Operating = approximately
32 VDC
• Heat Off = less than 1 VDC,
approximately 0.75 VDC
• Heating Failure = voltage
alternates between 32 VDC & 0.75
VDC
Cool Failure
Measure the voltage between
terminals J6-8 & J6-6.
• Cool Operating = approximately
32 VDC
• Cool Off = less than 1 VDC,
approximately 0.75 VDC
• Cooling Failure = voltage
alternates between 32 VDC & 0.75
VDC
To use LED's for quick status
information at the unit, purchase a
BAYSENS010B ZSM and connect
wires with alligator clamps to
terminals 6 through 10. Connected
each respective terminal wire (6
through 10) from the Zone Sensor to
the unit J6 terminals 6 through 10.
Note: If the system is equipped with
a programmable zone sensor,
(BAYSENS019A, or
BAYSENS023A), the LED
indicators will not function
while the BAYSENS010A is
connected.
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.
Note: Before resetting Cooling
Failures and Heating Lockouts
check the Failure Status
Diagnostics by the methods
previously explained.
Diagnostics will be lost when
the power to the unit is
disconnected.
Method 1
To reset the system from the space,
turn the MODE selection switch at the
zone sensor 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" .
Lockouts can be cleared through the
building management system. Refer
to the building management system
instructions for more information.
Zone Temperature Sensor (ZTS)
Service Indicator
The ZSM SERVICE LED is a generic
indicator that will signal the closing of
a Normally Open switch at any time,
providing the Indoor Motor (IDM) is
operating. This indicator is usually
used to indicate an airside fan failure.
The RTRM will ignore the closing of
this Normally Open switch for 2 (±1)
minutes. This helps prevent nuisance
SERVICE LED indications.
TTA-SVN03A-EN