Carrier 58DP - Manual (Page 8)

remain open until the thermostat is satisfied.
When the thermostat is satisfied, it will deenergize the main
gas valve and stop the gas flow. The vent damper motor will
energize and close the damper. When the vent damper
reaches the full-closed position, the damper motor is
deenergized and will remain so until the next “call for heat”
by the thermostat.
C. Cooling (Cooling Models Only)
When the thermostat “calls for cooHng,” power from trans­
former TRAN energizes the condensing unit contactor, cool­
ing relay coil CFR, closing its contacts and energizing
blower motor MTR on its cooling speed. It continues to
operate until the thermostat is satisfied.
When the thermostat is satisfied, the circuit to terminal Gc
is broken, deenergizing cooling relay coil CFR which, in
turn, opens its contacts, stopping blower motor MTR.
VIII. FILTER ARRANGEMENT
The two factory-supplied filters are shipped in the blower
compartment. After the return-air duct has been connected
to the furnace, install the filters in a V-formation inside the
retum-air plenum. See Fig. 12.
A WARNING
Never operate the unit without a filter or with the filter
access door removed. A failure to adhere to this warn­
ing can cause a fire, physical injury, or death.
A78654
Fig. 12—Position of Filters
IX. STARTUP AND ADJUSTMENT
In addition to the following information, refer to “Proce­
dures for Natural-Draft Gas-Fired Furnaces” packaged with
the unit.
NOTE:
There is a switch located in the blower compartment
that breaks the electrical power supply when the blower
access door is removed. Be sure the blower access door is
properly installed.
A CAUTION
This furnace is equipped with a fusible link in the vesti­
bule area that wQl melt if an overheating condition
caused by an inadequate combustion-air supply or
improper venting practices develops. Do not jumper
this fuse. Correct the condition and replace the fuse
with an identical part.
NOTE:
The gas valve regulator has been nominally-set at
3.5 in. wc for natural gas. Refer to “Procedures for Natural-
Draft Gas Furnace Installation” for readjusting when
checking input.
A. Adjustment of Blower Speed
A WARNING
Disconnect the electrical power before changing the
speed tap. A failure to adhere to this warning can cause
personal injury.
To change motor speed taps, remove the motor tap lead (See
Table 5.) and relocate it on the desired terminal on the plug­
in terminal block/speed selector located on the blower.
A CAUTION
When adjusting the blower speed, make certain that
the temperature rise across the heat exchanger does not
exceed that specified on the rating plate.
Table 5—Speed Selector
Speed Tap No.*t
Common C
Hi 1
Med-Hi 2
Med-Low 3
Low 4
♦Furnaces without a cooling fan relay are equipped with a 3-speed
motor.
fWhite wire from control box to common; black wire from control box
to cooling speed selection (when used); red wire from control box to
heating speed selection.
B. Automatic Gas Control Valve
These units are equipped with an automatic gas control
valve. If not already checked when lighting the main
burner, check the proper operation of this valve by moving
the room thermostat pointer above and below room temper­
ature and observing that the meiin burners light on “call for
heat” and go off when the pointer is moved below room tem­
perature setting.
NOTE:
For ease of adjusting the pilot flame, disconnect ter­
minal No. 1 at the gas valve. This will prevent main burner
ignition and allow time to adjust the pilot. Reconnect the
power lead after adjustment.
X. CARE AND MAINTENANCE
A CAUTION
Because of possible damage to the equipment or per­
sonal- injury, maintenance should be performed by qual­
ified persons only.
The gas service pressure must not exceed 0.5 psig (14
in. wc).
A WARNING
Never store anything on, or in contact with, the fur­
nace, such as:
1. Spray or aerosol cans, rags, brooms, dust mops,
vacuum cleaners, or other cleaning tools.
2. Soap powders, bleaches, weixes or other cleaning
compounds, plastic or plastic containers, gasoline,
kerosene, cigarette lighter fluid, dry cleaning fluids,
or other volatile fluids.
3. Paint thinners and other painting compounds,
paper bags or other paper products.
A failure to adhere to this warning can cause corrosion
of the heat exchanger and vent system, fire, personal
injmy, or death.
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