312AAV
SERVICE AND MAINTENANCE
PROCEDURES
!WARNING
FIRE, PERSONAL INJURY AND UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal injury, death and/or property damage.
The ability to properly perform maintenance on this equipment requires certain knowledge, mechanical skills, tools, and equipment. If you do not possess these, do not attempt to perform any maintenance on this equipment other than those procedures recommended in the User’s Manual.
!WARNING
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury or death.
Before installing, modifying, or servicing system, main electrical disconnect switch must be in the OFF position and install a lockout tag. There may be more than one disconnect switch. Lock out and tag switch with a suitable warning label. Verify proper operation after servicing.
!CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in improper unit operation or failure of unit components.
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation.
!CAUTION
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in environmental pollution.
Remove and recycle all components or materials (i.e. oil, refrigerant, control board, etc.) before unit final disposal.
Step 1 — Introduction
GENERAL
These instructions are written as if the furnace is installed in an upflow application. An upflow furnace application is where the blower is located below the combustion and controls section of the furnace, and conditioned air is discharged upward. Since this furnace can be installed in any of the 4 positions shown in Fig. 4, you must revise your orientation to component location accordingly.
ELECTRICAL CONTROLS AND WIRING
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
There may be more than one electrical supply to the furnace. Check accessories and cooling unit for additional electrical supplies that must be shut off during furnace servicing. Lock out an tag switch with a suitable warning label.
The electrical ground and polarity for
NOTE: If the polarity is not correct, the STATUS LED on the control will flash rapidly and prevent the furnace from heating. The control system also requires an earth ground for proper operation of the control and
The
Proper instrumentation is required to service electrical controls. The control in this furnace is equipped with a Status Code LED
For an explanation of status codes, refer to service label located on blower access door or Fig. 51, and the troubleshooting guide which can be obtained from your distributor.
See Fig. 56 for a brief Troubleshooting guide.
For Controls with an Amber LED
The stored status codes will NOT be erased from the control memory, if 115- or
1. To retrieve status codes, proceed with the following:
NOTE: NO thermostat signal may be present at control, and all
a.Leave
b.Remove outer access door.
c.Look into blower access door sight glass for current LED status.
d.BRIEFLY remove insulated terminal wire from the draft safeguard (DSS) switch until LED goes out, then recon- nect it.
NOTE: If wire to DSS is disconnected longer than 4 sec, main blower starts, and retrieval request is ignored.
2.When above items have been completed, the LED flashes status code 4 times. Record this status code for further troubleshooting. After the LED flashes status code four times, BRIEFLY remove wire again from DSS switch un- til LED goes out, then reconnect it to retrieve previous status code (if available). Repeat as needed for more previ- ous status codes or until Code 11 appears.
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