SL* / BL* Series Air Handler Installation Guide Page 4
INSTALLATION GUIDE
Change the lter every 30 days or as soon as dust or dirt
appear on the lter. Failure to change the lter in a timely
fashion can result in reduced air ow, increased operating
cost, and may result in damage to the indoor unit and/ or
outdoor unit.
THERMOSTAT
Select a thermostat that is commonly referred to as a single
stage cooling with electric heat sub base. This thermostat
will energize the fan on a demand for heat or cool.
Install the thermostat on an inside wall, away from drafts,
lights, or other heat sources in a location that has good air
circulation from the other rooms being controlled by the
thermostat. The thermostat should be mounted 4 to 5 feet
above the oor.
START UP
Once all connections are completed, the unit should be
started up, and a check of the completed system should
be performed. Before performing any system test make
sure that all grilles, registers, and dampers are open and
set to the correct positions. Also make certain that an air
lter is installed in the return air prior to the Air Handler. A
performance test should be completed in accordance with
the outdoor equipment manufacturer’s instructions. Airow
test should be conducted in the heating and cooling modes
to ensure satisfactory operation.
SEQUENCE OF OPERATION
Cooling. (Cooling only or heat pump with reversing valve
energized in heat mode). When the thermostat calls for
cooling, the blower relay is energized. The N.O. contacts will
close, after a time delay, and the indoor blower will operate.
The circuit between R and Y is complete. Which allows
the contactor on the outdoor equipment to close, start the
compressor and the outdoor fan motor.
Cooling. (Heat pump with reversing valve energized in
cooling mode). When the thermostat calls for cooling, the
circuit between R and G, and R and O is complete. Circuit R
and O energizes the reversing valve to the cooling position.
Circuit R and O energizes the blower relay. The N.O.
contacts will close, after a time delay, and the indoor blower
will operate. The circuit between R and Y is complete, which
allows the contactor on the outdoor equipment to close, and
start the compressor and outdoor fan motor.
Heating. (Electric heat only). When the thermostat
calls for heat, the circuit between R and W is complete,
and the heat sequencer is energized. A time delay will
occur, allowing the heating element(s) and the indoor
blower motor to come on.
Heating. (Heat pump reversing valve energized
in heat mode). When the thermostat calls for heat,
the circuits between R and B, R and Y, and R and G
are complete. Circuit R and B energize the reversing
valve, switching it to the heat position. Circuit R and
Y energized the outdoor unit contactor, starting the
compressor and outdoor fan. Circuit R and G energizes
the blower relay, starting the blower motor.
If the indoor room temperature should continue to fall,
circuit R and W2 is by the second-stage heat bulb
on the thermostat. Circuit R-W2 energizes the heat
sequencer. The completed circuit will energize the
supplemental electric heat.
Blower Time Delay. This unit is equipped with timed
on and a timed off relay. This relay delays the start and
delays the stopping of the indoor fan motor to maximize
the efciency of the unit.
Defrost. When the unit starts the defrost cycle,
supplemental heat during defrost can be provided by
connecting B on the blower coil to the defrost relay on
the outdoor heat pump. This will complete the circuit
between R and B in the blower coil, through a set of
contacts in the defrost relay in the outdoor unit. This
circuit, when it is connected, will help prevent cold air
from being discharged from the indoor unit during the
defrost mode.
MAINTENANCE
The system air lter(s) should be inspected, cleaned,
or replaced at least monthly. If the lter is mounted
internal to the unit, make sure that electrical power is
disconnected before removing the access panels. Make
certain that the access panels are replaced and secured
properly before placing the unit back in operation. This
product is designed for dependable service however,
periodic maintenance should be scheduled to be
conducted by a trained professional service personnel.
This unit service should be conducted at least annually,
and should include testing, inspection of electrical and
refrigerant components. The heat transfer surface
should be cleaned. The blower motor is permanently
lubricated for normal operating conditions.
