Secondary Heat Exchangers; Flushing Collector Box And Drainage System - Carrier 58MTB Service And Maintenance Instructions

13. Refer to furnace wiring diagram and reconnect wires to
flame rollout switch, gas valve, igniter, and flame sensor.
14. Reconnect pressure switch tubes to gas valve and intake
housing. Refer to tube routing label on main furnace door
or Fig. 10 for proper tube location. Be sure tubes are not
kinked.
15. Turn on gas and electrical supplies to furnace.
16. Check furnace operation through 2 complete heat operating
cycles. Look through sight glass in burner enclosure to
check burners. Burner flames should be clear blue, almost
transparent. (See Fig. 11.)
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result in
serious injury, death, or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically for the
detection of leaks to check all connections.
17. Check for gas leaks.
18. Replace main furnace door.

Secondary Heat Exchangers

NOTE: The condensing side (inside) of the secondary heat
exchangers CANNOT be serviced or inspected. A small number
of bottom outlet openings can be inspected by removing the
inducer assembly. See Flushing Collector Box and Drainage
System section for details on removing inducer assembly.
Step 5 — Flushing Collector Box and Drainage
System
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Disconnect inducer motor and pressure switch wires or con-
nectors.
4. Disconnect pressure switch tubes.
5. Disconnect vent pipe from inducer housing outlet by
loosening coupling clamp on inducer outlet.
6. Disconnect drain tube from inducer housing. (See Fig. 10.)
NOTE: Ensure the drain tube disconnected from the inducer
housing is higher than the collector box opening or water will flow
out of tube.
7. Remove inducer housing assembly by removing 4 bolts at-
taching assembly to cell panel.
8. Flush inside of collector box with water until discharge
from condensate trap is clean and runs freely.
9. Inspect inside area of collector box for any pieces of foreign
materials and remove them if present.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in furnace component
damage.
DO NOT use wire brush or other sharp object to inspect or
dislodge materials in secondary heat exchangers as cutting the
secondary heat exchanger protective coating may occur. Flush
with water only.
10. Reassemble inducer assembly by reversing items 5-7. Tight-
en vent coupling clamp screw(s) to 15 in.-lb of torque.
NOTE: If seal between the inducer housing and the collector box
is damaged in any way, it must be repaired. To repair, apply
sealant releasing agent such as PAM cooking spray or equivalent
(must not contain corn nor canola oil, halogenated hydrocarbons
nor aromatic content, to prevent inadequate seal from occurring) to
inducer housing. Apply a small bead of G.E. RTV 162, G.E. RTV
6702, or Dow- -Corning RTV 738 sealant to groove in collector
box. (See Fig. 12.)
11. Refer to furnace wiring diagram and reconnect wires to in-
ducer motor and pressure switches or connectors.
12. Reconnect pressure tubes to pressure switches. See diagram
on main furnace door for proper location of tubes. Be sure
tubes are not kinked. (See Fig. 10.)
13. Turn on gas and electrical supplies to furnace.
14. Check furnace operation through 2 complete heat operating
cycles. Check area below inducer housing, vent pipe, and
condensate trap to ensure no condensate leaks occur. If
leaks are found, correct the problem.
WARNING
!
ELECTRICAL OPERATION HAZARD
Failure to follow the safety warnings exactly could result in
serious injury, death, or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically for the
detection of leaks to check all connections.
15. Check for gas leaks.
16. Replace main furnace door.
RTV
Combustion- - Air Intake Housing
Fig. 9 - -
Gasket Repair
8
PAM
A93087