TTA-SVX02C-EN
21
Unit Start-Up
Once the unit is properly installed and pre-start procedures
are complete, start the unit by turning the System Switch on
the indoor thermostat to either HEAT, COOL or AUTO. The
system should operate normally.
CAUTION:
Ensure the disconnect for the indoor air
handler is closed before operating the system. Operating
the indoor unit without the indoor fan energized, can
cause unit trip-out on high pressure control and/or liquid
flood back to the compressor.
Sequence of Operation
Electro-Mechanical Controls
Unit Model Number Digits 9 and 10 = 00 or 0S
General
Operation of the system cooling (and optional heating) cycles
is controlled by the position of the system switch on the room
thermostat. Once the system switch is placed in either the
HEAT
or
COOL
position, unit operation is automatic. The
optional automatic changeover thermostat, when in the
AUTO
position, automatically changes to heat or cool with sufficient
room temperature change.
Evaporator Fan (Indoor Supply Air)
The evaporator fan is controlled by an
ON/AUTO
switch on
the room thermostat. With the switch positioned at
AUTO
and
the system operating in the cooling mode, fan operation
coincides with the cooling run cycles. If the system is
equipped with heat and is operating in the heating mode while
the fan switch is at
AUTO
, fan operation coincides with the
heating run cycles. When the fan switch is positioned at
ON,
fan operation is continuous.
System Start Procedure
Electro Mechanical Controls
Cooling Mode
With the disconnect switch in the
ON
position, current is
supplied to the compressor sump heater(s) and control
transformer. The sump heater(s) supplies heat to the
compressor(s) during the
“Off”
cycle. The transformer steps
down the line voltage to 24V for the low voltage control circuit.
With the room thermostat system switch is positioned at
COOL
and the fan switch is at
AUTO
, the compressor
contactor energizes on a call for cooling. When the contacts of
the compressor contactor close, operation of the compressor
and condenser fan begins. The evaporator fan contactor also
energizes on a call for cooling and initiates evaporator fan
operation.
On units with dual circuits, the second stage of cooling is
initiated as a result of the 2-stage thermostat calling for
additional cooling.
Содержание TTA075AD series
Страница 19: ...TTA SVX02C EN 19 Installation Figure 11 Typical Split System Cooling...
Страница 31: ...31...
