Clean Burners - Carrier 58MCA Service And Maintenance Instructions

f. Remove blower wheel from housing.
g. Clean wheel per instructions on degreaser cleaner.
9. Reassemble motor and blower wheel by reversing items 8.b.
through 8.f. Ensure wheel is positioned for proper rotation.
NOTE: Be sure to reattach ground wire on fixed-capacity fur-
naces (58MCA or 58MXA).
10. Reinstall blower assembly in furnace.
11. Reinstall condensate trap and tubing if previously removed.
a. Reinstall condensate trap in hole in blower shelf.
b. Connect condensate trap drain tubes. See Fig. 8 or 9 or
tubing diagram on main furnace door for proper tube
location.
(1.) Connect 1 tube (blue or blue and white striped) from
collector box.
(2.) Connect 1 tube (violet or unmarked) from inducer
housing.
(3.) Connect 1 tube (relief port, green or pink) from
collector box.
c. Connect field drain to condensate trap.
NOTE: Ensure tubes are not kinked or pinched, as this will affect
operation.
12. Reinstall control box, transformer, and door switch assembly
on blower shelf.
13. Reconnect wires.
a. Fixed-capacity furnaces (58MCA or 58MXA)
Refer to furnace wiring diagram, and connect thermostat
leads if previously disconnected. (See Fig. 18.)
NOTE: Refer to Table 1 for motor speed lead relocation if leads
were not identified before disconnection.
Table 1—Speed Selector (58MCA or 58MXA Only)
COLOR SPEED
Black
Yellow (When Present) Medium High
Blue Medium Low
Red
White Common
Heating speed selection MUST be adjusted to provide proper
temperature rise as specified on the rating plate. Failure to
adjust the heating speed may shorten heat exchanger life.
b. Variable-capacity furnaces (58MVP)
(1.) Refer to furnace wiring diagram, and connect motor
and auxiliary limit switch leads. (See Fig. 22.)
(2.) Connect thermostat leads if previously disconnected.
14. Turn on electrical supply. Manually close blower access panel
door switch, and check for proper rotation and speed changes
between heating and cooling by jumpering R to G and R to Y
on control center thermostat terminals. (See Fig. 13.)
FACTORY ATTACHED TO
High Cool
Spare
Heat
Low Spare
Com
Blower access panel door switch opens 24-v power to control
center. No component operation can occur. The 115-v power
is still present at control center and transformer. Caution must
be taken when manually closing this switch for service
purposes. Failure to follow this warning could result in
personal injury or death.
15. If furnace is operating properly, release blower access panel
door switch, replace blower access panel, and replace main
furnace door.
Step 3—Clean Burners
The following items should be performed by a qualified service
technician. If the burners develop an accumulation of light dirt or
dust, they may be cleaned by using the following procedure:
1. Turn off gas and electrical supplies to furnace.
2. Remove furnace door.
3. Remove burner box cover.
4. Using backup wrench, disconnect gas supply pipe from gas
valve.
5. Remove wires from gas valve. Note location for reassembly.
6. Remove burner box pressure tube from gas valve regulator
fitting.
7. Remove screws that secure manifold to burner box. (See Fig.
5.)
MANIFOLD
MOUNTING
SCREW
Fig. 5—Burner Box Assembly
8. Remove manifold, orifices, and gas valve as 1 assembly.
9. Remove screws attaching burner assembly in burner box.
10. Remove burner assembly from burner box.
NOTE: All burners are attached to burner bracket and can be
removed as 1 assembly.
11. Clean burners with soft brush and vacuum.
12. Reinstall manifold, orifice, and gas valve assembly in burner
box. Ensure manifold seal grommet is installed properly and
burners fit over orifices.
13. Reconnect wires to gas valve. Refer to furnace wire schematic
for proper wire location.
4
MANIFOLD
GAS VALVE
REGULATOR
FITTING
GAS VALVE
A93295