(47.6 mm)
A05026
Fig. 47 --- Igniter Position-Top View
A01050
Fig. 48 --- Cleaning Heat Exchanger Cell
(4)Insert brush end of cable in burner inlet opening of cell, and proceed to clean 2 lower passes of cell in same manner as upper pass.
(5)Repeat foregoing procedures until each cell in furnace has been cleaned.
(6)Using vacuum cleaner, remove residue from each cell.
(7)Using vacuum cleaner with soft brush attachment, clean burner assembly.
(8)Clean flame sensor with fine steel wool.
(9)Install NOx baffles (if removed).
(10)Reinstall burner assembly. Center burners in cell openings.
10.Remove old sealant from cell panel and collector box flange.
11.Spray releasing agent on the heat exchanger cell panel where collector box assembly contacts cell panel.
NOTE: A releasing agent such as cooking spray or equivalent (must not contain corn or canola oil, aromatic or halogenated hydrocarbons or inadequate seal may occur) and RTV sealant (G.E. 162, 6702, or
12.Apply new sealant to flange of collector box and attach to cell panel using existing screws, making sure all screws are secure.
13.Reconnect wires to the following components. (Use con- nection diagram on wiring label, if wires were not marked for reconnection locations.):
a.Draft safeguard switch.
b.Inducer motor.
c.Pressure switch(es).
d.Limit
e.Gas valve.
f.Hot surface igniter.
g.
h.Flame rollout switches.
i.Install NOx baffles (if removed).
14.Reinstall internal vent pipe, if applicable.
15.Reinstall vent connector on furnace vent elbow. Securely fasten vent connector to vent elbow with 2
16.Replace blower access door only, if it was removed.
17.Set thermostat above room temperature and check furnace for proper operation.
18.Verify blower airflow and speed changes between heating and cooling.
!WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death and/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.
19.Check for gas leaks.
20.Replace outer access door.
Step 3 —Sequence of Operation
NOTE: Furnace control must be grounded for proper operation or control will lock out. Control is grounded through green/yellow wire routed to gas valve and manifold bracket screw.
Using the schematic diagram in Fig. 41, follow the sequence of operation through the different modes. Read and follow the wiring diagram very carefully.
NOTE: If a power interruption occurs during a call for heat (W), the control will start a
The blower door must be installed for power to be conducted through the blower door interlock switch ILK to the furnace control CPU, transformer TRAN, inducer motor IDM, blower motor BLWM,
1.Heating
(See Fig. 26 for thermostat connections.) The wall thermo- stat “calls for heat,” closing the
a.Inducer Prepurge Period- As the inducer motor IDM comes up to speed, the pressure switch contacts PRS close, 24 VAC power is supplied for a field in- stalled humidifier at the HUM terminal and the control begins a
b.Igniter
c.
310AAV
47