Trane ReliaTel Diagnostic Manual page 76

Operation with a Conventional Thermostat (Constant Volume)
a field applied time clock with relay contacts connected to J6-11 and J6-12 can initiate an
unoccupied mode as follows:
Contacts open: Normal occupied operation.
Contacts closed: Unoccupied operation as follows - Fan in auto mode regardless of fan switch
position. Economizer closes except while economizing regardless of minimum position setting.
Cooling/Economizer Operation:
If unit does not have an economizer, the Cool/Econ Stage 1 and Stage 2 will call directly for
mechanical cooling (compressor) stages. If the unit has an economizer, the Cool/Econ stages will
function as follows.
Table 25. Cooling/Economizer Operation with Thermostat
OK to
Economize?
No
No
No
Yes
Yes
Yes
76
Thermostat
Y1
On
Off
On
On
Off
On
40 to 50 ton CV only.
This unit has 3 stages of cooling if using a zone sensor or binary inputs as shown above.
If using a conventional thermostat it has 2 stages as follow:
Y1 = 1st stage
Y1 + Y2 = 3rd stage
VAV
Thermostat inputs are ignored on VAV units.
Call for
Thermostat Economizer
Y2 Cooling
Off Inactive
On Inactive
On Inactive
Off Active
On Active
On Active
Compressor
Staging
Request
Compressor
Output 1
Compressor
Output 2
Compressor
Outputs 1 & 2
Off
Off
Compressor
Output 1
RT-SVD03G-EN