Secondary Heat Exchangers; Flushing Collector Box And Drainage System - Carrier 58MCB Service And Maintenance Instruction

burners. Burner flames should be clear blue, almost transpar-
ent. (See Fig. 11.)
→
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 commer-
cially 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
connectors.
4. Disconnect pressure switch tubes.
5. Disconnect vent pipe from inducer housing outlet by loosen-
ing 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
attaching 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.
BURNER FLAME
MANIFOLD
Fig. 11—Burner Flame
→
UNIT DAMAGE HAZARD
Failure to follow this caution may result in furnace compo-
nent 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. Tighten
→
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 or canola oil, halogenated hydrocarbons nor
aromatic content, to prevent inadequate sealing), to inducer hous-
ing. (See Fig. 12.) Apply a small bead of G.E. RTV 162, G.E. RTV
6702, or Dow-Corning RTV 738 sealant to groove in collector
box.
11. Refer to furnace wiring diagram and reconnect wires to
12. Reconnect pressure tubes to pressure switch. See diagram on
13. Turn on gas and electrical supplies to furnace.
14. Check furnace operation through 2 complete heat operating
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 commer-
cially available soap solution made specifically for the
detection of leaks to check all connections. A fire or explo-
sion may result causing property damage, personal injury, or
loss of life.
15. Check for gas leaks.
BURNER
A89020
8
the vent coupling clamp screw(s) to 15 in.-lb. of torque.
inducer motor and pressure switch or connectors.
main furnace door for proper location of tubes. Be sure tubes
are not kinked. (See Fig. 10.)
cycles. Check area below inducer housing, vent pipe, and
condensate trap to ensure no condensate leaks occur. If leaks
are found, correct the problem.
PAM
RTV
Fig. 12—Gasket on Collector Box
A93081