Johnson Controls AC8B - Manual (Page 2)

343787-UUM-B-0409
2 Unitary Products Group
FAN OPERATION SELECTION
A multi-position fan switch allows you to choose the type of fan opera-
tion of the indoor fan.
AUTO
With the thermostat fan switch set to “AUTO”, the fan will run intermit-
tently as required for either heating or cooling. This position will provide
the lowest operating cost. If you purchased one of our thermostats, they
have an Intelligent fan mode which continually circulates the air during
occupied modes or when you are at home, and can cycle the fan during
unoccupied mode or during the night while you sleep to further con-
serve energy.
ON
CONTINUOUS FAN OPERATION: With the thermostat fan switch set to
“ON”, the indoor fan will not shut off. However, the cooling (AC) or heat-
ing (heat pump) systems will still operate as required by room tempera-
tures. This provides continuous air filtering and more even temperature
distribution to all conditioned spaces.
FAN ONLY OPERATION: On moderate days, usually during spring and
fall, when neither heating nor cooling is required, you may want to run
only the fan to ventilate, circulate and filter the air in your home or build-
ing. Set the comfort control switch to “OFF” and the fan switch to “ON”.
Be sure to return the switches to their original positions for normal oper-
ation.
START-UP
The maximum and minimum conditions for operation must be observed
to assure a system that will give maximum performance with minimum
service.
The comfort control switch is assumed to be in the “OFF” position. If the
main power supply to the outdoor and indoor units is off, turn the appro-
priate disconnects to the “ON” position. Place the system into operation
as follows:
1. Set temperature adjustment to the desired temperature on your
thermostat.
COOLING - The higher the setting, the lower the amount of energy con-
sumed. Federal Guidelines recommend a setting of 78 °F.
HEATING - The lower the setting, the lower the amount of energy con-
sumed. Federal guidelines recommend a setting of 65 °F or lower.
NOTE: If your cooling and heating temperature adjustments are sepa-
rate, be sure to set both.
2. After considering “Fan Operation Selection” above, select and set
the fan operation mode you desire.
3. Move the comfort control switch to the desired mode of operation
(Cooling or Heating) found on your particular thermostat.
POWER FAILURE
When accidents, wind storms, etc. disrupt electrical power supply to
your house, switch thermostat to “OFF” position.
SYSTEM OPERATION
MANUAL CHANGE-OVER THERMOSTAT
COOLING YOUR HOME: With the comfort control switch in the
“COOL” position, the system will operate as follows: When the indoor
temperature rises above the level indicated by the temperature adjust-
ment setting, the system will start. The outdoor unit will operate and the
indoor fan will circulate the cooled, filtered air. When the room tempera-
ture is lowered to the setting selected, the system will shut off.
HEATING YOUR HOME: If your system includes a heating unit and the
comfort control switch is in the “HEAT” position, the system will operate
as follows: When the indoor temperature drops below the level indi-
cated by the temperature adjustment setting, the system will start. The
heating system will operate and the indoor fan will circulate the filtered
air. When the room temperature rises to the setting selected, the sys-
tem will shut off. Whether heating or cooling, the fan will continue to
operate if the fan switch was set in the “ON or Intelligent” position. The
“AUTO” setting on the fan switch will allow the fan to shut off when your
system does.
ELECTRONIC THERMOSTAT
The computerized electronic thermostat, when programmed, will func-
tion automatically to operate the system as follows: When the indoor
temperature rises above the higher (COOL) setting, the outdoor unit will
operate and the indoor fan will circulate the cooled, filtered air. When
the room temperature is lowered to the selected level, the system will
shut off. The indoor fan will either shut off or run continuously, depend-
ing upon your choice of fan switch setting. When the indoor tempera-
ture drops below the lower (HEAT) setting, the heating system will
operate, and the indoor fan will circulate the heated, filtered air. When
the indoor temperature rises to the selected setting, the system will shut
off. The indoor fan will either shut off or run continuously, depending
upon your choice of fan switch setting.
CARE OF SYSTEM
It is strongly recommended that regular periodic preventative mainte-
nance be performed on this equipment. The person most familiar with
the equipment in your H.V.A.C. system is a dealer. The dealer can
ensure your maintenance program meets the conditions of the War-
ranty”, maximize the efficiency of the equipment, and service your unit
within the federally mandated guidelines with regard to unlawful dis-
charge of refrigerants into the atmosphere.
FIGURE 1: Programmable Electronic Thermostat
FIGURE 2: Programmable Electronic Thermostat
TABLE 1: APPLICATION LIMITATIONS
Air Temperature at
Outdoor Coil, °F
Air Temperature at
Indoor Coil, °F
Min. Max. Min. Max.
DB
Cool
DB
Heat
DB
Cool
DB
Heat
WB
Cool
DB
Heat
WB
Cool
DB
Heat
60 -10 115 75 57 50 1
1. Operation below this temperature is permissible for a short period of
time, during morning warm-up.
72 80