Trane TSH 060, TSD manual Setting the economizer or 0-50% motorized hood option, Unoccupied mode

Operation

Unoccupied mode

If the thermostat being used is programmable, it will have its own strategy for unoccupied mode and will control the unit directly. If a mechanical thermostat is being used, 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 shown in Table 46.

Setting the economizer or 0-50% motorized hood (option)

The ECA board is mounted on the damper actuator. To access the ECA board on economizers:

•Remove the filter access panel of the unit.

•The electrical power must be disconnected to set the minimum position and check the economizer.

•Disconnect the power supply, put the thermostat fan selector to "ON" and the "HEAT/COOL" selector to "OFF". This puts the damper in the minimum ventilation position.

•To set the required minimum ventilation air position, turn the dial on the ECA clockwise to increase ventilation, or anti- clockwise to decrease ventilation. The damper will open at this setting whenever the fan circuit is powered up (see Figure 25).

•When the arrow on the dial's adjustment screw is pointing to 8 o'clock, the minimum position is roughly 0%. When the dial is pointing to 12 o'clock it is roughly 25%, and when the dial is pointing to 4 o'clock it is roughly 50% (see figure 25).

Table 46 - Cooling/Economizer Operation with Thermostat

OK to	Thermostat Thermostat		Call for Economizer	Compressor Staging
Economize?	Y1	Y2	Cooling	Request
No	On	Off	Inactive	Compressor Output 1
No	Off	On	Inactive	Compressor Output 2
No	On	On	Inactive	Compressor
				Outputs 1 & 2
Yes	On	Off	Active	Off
Yes	Off	On	Active	Compressor off
Yes	On	On	Active	Compessor

Notes:

40 to 50 ton CV only

This unit has 3 stages of cooling if using a zone sensor. If using a conventional thermostat it has 2 stages as follows:

Y1 = 1st stage

Y1 + Y2 = 3rd stage

VAV

Thermostat inputs are ignored on VAV units.

50 RT-SVX20A-E4