Carrier PG80MSU Installation, Start-Up, Operating And Service And Maintenance Instructions page 33

PG80MSU: Installation, Start-up, Operating and Service and Maintenance Instructions
of gas valve outlet pressure, insufficient or poor quality combustion air,
incorrect size or damaged orifice(s), improper gas, or a restricted heat
exchanger. Action must be taken to correct the problem.
If it becomes necessary to clean the heat exchangers because of dust or
corrosion, proceed as follows:
1. Turn OFF gas and electrical power to furnace.
2. Remove outer access door.
3. Disconnect vent connector from furnace vent elbow.
4. Disconnect wires to the following components. Mark wires to aid in
reconnection of (be careful when disconnecting wires from
switches because damage may occur):
a. Inducer motor
b. Transducer
c. Limit over-temperature switch
d. Gas valve
e. Hot surface igniter
f. Flame-sensing electrode
g. Burner thermal switch
h. DSS Draft Safeguard
5. Remove screws that fasten the inducer cover assembly to the cell
panel. Be careful not to damage the collector box. Inducer assembly
and elbow need not be removed from collector box.
6. Disconnect gas supply line from gas valve.
7. Remove screws that attach the burner assembly to the cell panel.
The gas valve and burners tube need not be removed from burner
box.
NOTE: Be very careful when removing burner assembly to avoid
breaking igniter.
8. Remove insulation assembly from burner tube inlets.
NOTE: Proper use of Personal Protective Equipment (PPE) must be
followed, including safety glasses, gloves, and dust mask when
removing and reinstalling the heat exchanger insulation assembly.
9. Using field-provided large caliber rifle cleaning brush, 36-in. (914
mm) long steel spring cable, a variable speed, reversible electric
drill, and vacuum cleaner, clean cells as follows:
NOTE: The materials needed in item NO TAG can usually be purchased
at local hardware stores.
a. Remove metal screw fitting from wire brush to allow insertion
into cable.
b. Insert the twisted wire end of brush into end of spring cable, and
crimp tight with crimping tool or crimp by striking with
ball-peen hammer. TIGHTNESS IS VERY IMPORTANT.
Fig. 38 – Igniter Position
(1.) Attach variable-speed, reversible drill to the end of spring
cable (end opposite brush).
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
(2.) Insert brush end of cable into the outlet opening of cell and
slowly rotate with drill. DO NOT force cable. Gradually
insert cable into upper pass of cell, see
(3.) Work cable in and out of cell 3 or 4 times to obtain sufficient
cleaning. DO NOT pull cable with great force. Reverse drill
and gradually work cable out.
(4.) Insert brush end of cable in burner inlet opening of cell, and
proceed to clean two 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.) Reinstall the insulation assembly.
NOTE: If insulation assembly is damaged, do not attempt to repair,
must be replaced with insulation kit.
NOTE: Proper use of Personal Protective Equipment (PPE) must be
followed, including safety glasses, gloves, and dust mask when
removing and reinstalling the heat exchanger insulation assembly.
(10.)Reinstall burner assembly.
10. Remove old sealant from cell panel and collector box flange.
11. Spray releasing agent on the heat exchanger cell panel where
inducer cover 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
Dow-Corning 738) are needed before starting installation.
NOTE: DO NOT substitute any other type of RTV sealant.
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 connection
diagram on wiring label, if wires were not marked for reconnection
locations.):
a. Burner thermal switch
b. Inducer motor
c. Transducer
d. Limit over-temperature switch
e. Gas valve
f. Hot surface igniter
g. Flame-sensing electrode
h. DSS Draft Safeguard
14. Reinstall vent connector on furnace vent elbow. Securely fasten
vent connector to vent elbow with two (2) field-supplied,
corrosion-resistant, sheet metal screws located 180° apart.
15. Replace blower access door only, if it was removed.
16. Set thermostat above room temperature and check furnace for
proper operation.
17. Verify blower airflow and speed changes between heating and
cooling.
18. Check for gas leaks.
19. Replace outer access door.
A180230
33
Fig. 39.