Carrier 58MXA Furnace User Manual


 
Fig. 16—Service Label
A99107
SERVICE
COMPONENT TEST
To initiate the component test sequence,shut OFF the room thermostat or
disconnect the "R" thermostat lead. Briefly short the TEST terminal to the "Com
24V" terminal. Status LED will flash code and then turn ON the inducer motor. The
inducer motor will run for the entire component test. The hot surface ignitor,
blower motor-heat speed, and blower motor-cool speed will be turned ON for
10-15 seconds each. Gas Valve and Humidifier will not be turned on.
G
R
Y
W
Com
HUM
TEST
STATUS
320615-102 REV. J
CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and
SEC-2.
CONTINUOUS ON - Control has 24V power.
RAPID FLASHING - Line voltage (115V) polarity reversed. If twinned, refer to
twinning kit instructions.
LED CODE
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST
DIGIT DETERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY
THE NUMBER OF LONG FLASHES.
STATUS
24V
11 NO PREVIOUS CODE - Stored status codes are erased when power
(115V or 24V) to control is interrupted or 48 hours after each fault is cleared.
12 BLOWER ON AFTER POWER UP (115V or 24V) - Blower runs for 90 seconds,
if unit is powered up during a call for heat (R-W closed).
13 LIMIT OR FLAME ROLL-OUT SWITCH LOCKOUT - Control will auto reset after
three hours unless flame roll-out switch or fuse link is opened, refer to #33.
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT - Control will NOT auto reset.
Check for:- Mis-wired gas valve -Defective control (valve relay)
22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is
de-energized. Inducer will run until fault is cleared.
Check for: - Leaky gas valve -Stuck-open gas valve
23 PRESSURE SWITCH (ES) DID NOT OPEN Check for:
- Obstructed pressure tubing. - Defective pressure switch (stuck closed).
24 SECONDARY VOLTAGE FUSE IS OPEN
Check for:- Short circuit in secondary voltage (24V) wiring.
31 PRESSURE, DRAFT SAFEGUARD, AUXILIARY-LIMIT (when used), OR BLOCKED
VENT SHUTOFF (when used) SWITCH DID NOT CLOSE OR REOPENED - If open
longer than five minutes, inducer shuts off for 15 minutes before retry.
Check for: - Inadequate Combustion air supply.
- Proper vent sizing and condensate pitch or sag
- Low inducer voltage.
- Vent restriction or high winds.
- Disconnected or obstructed pressure tubing
- Defective inducer motor or start capacitor.
- Defective pressure switch or connections. If it opens after trial for ignition
period, blower will come on for 90 second recycle delay.
33 LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN - If open longer than three
minutes, code changes to #13. Flame roll-out switch requires manual reset.
Check for: - Defective blower motor or capacitor.
- Dirty filter or restricted duct system.
- Loose blower wheel.
- Defective switch or connections.
- Inadequate Combustion air supply (Flame Roll-out Switch or fuse link).
- Open Flame Roll-out switch,or fuse link. Manual reset or replace.
34 IGNITION PROVING FAILURE - Control will try three more times before a
lockout #14 occurs. If flame signal lost after trial for ignition period, blower
will come on for 90 second recycle delay. Check for:
- Oxide buildup on flame sensor (clean with fine steel wool).
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal).
- Gas valve defective or gas valve turned off.
- Defective Hot Surface Ignitor
- Manual valve shut-off.
- Low inlet gas pressure.
- Green wire MUST be connected to furnace sheet metal.
- Inadequate flame carryover or rough ignition.
If status code recall is needed, do not remove power or blower door. Briefly remove and then
reconnect one main limit wire to display stored status code.
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