Midea A2L Troubleshooting Manual

96% afue gas furnace

Hide thumbs

Table Of Contents

Table of Contents

Quick Links

Download this manual

A2L 96% AFUE Gas Furnace

Troubleshooting Guide

Table of Contents

Troubleshooting

Need help?

Do you have a question about the A2L and is the answer not in the manual?

Questions and answers

Summary of Contents for Midea A2L

Page 1 A2L 96% AFUE Gas Furnace Troubleshooting Guide...
Page 2: A P P N E X I D - A E S U Q N E E C F O P O R E I T A N
2 | 96% AFUE Gas Furnace Troubleshooting Guide Data subject to change...
Page 3: Table Of Contents
Troubleshooting Guide 96% AFUE Gas Furnace | 3 Table of Contents r t s o i t s l o y t e s e l i t o e l E r t c t s o i t a c s i e g r c e r...
Page 4: Key To Symbols And Safety Instructions
4 | 96% AFUE Gas Furnace Troubleshooting Guide 1 Key to Symbols and Safety Instructions 1.2 Safety Please read all instruction in the manual and retain all manuals for future 1.1 Key to Symbols reference. Warnings WARNING: Untrained personnel (homeowners) may only clean ...
Page 5 Troubleshooting Guide 96% AFUE Gas Furnace | 5 WARNING: FOLLOW ALL SAFETY CODES WARNING: FIRE, EXPLOSION Wear safety glasses, protective clothing, and work Check entire gas assembly for leaks after lighting this   gloves. Have a fire extinguisher available. Read these appliance.
Page 6: Troubleshooting
6 | 96% AFUE Gas Furnace Troubleshooting Guide 2 Troubleshooting 2.2 Resetting From Lockout Furnace lockout results when a furnace is unable to achieve ignition after three attempts. Refer to the troubleshooting chart on the following pages for assistance in determining the source of unit operational problems. WARNING: FIRE,EXPLOSION AND ASPHYXIATION The red diagnostic LED blinks to assist in troubleshooting the unit.
Page 7: Error Flash Codes
Troubleshooting Guide 96% AFUE Gas Furnace | 7 3 Error Flash Codes 3.1 No Light and No Fan (System Does Not Start Normally) Troubleshooting Chart Start Correct Are there any wiring loose wires or wrong according to connections? wiring diagram Is there Is the door Replace the...
Page 8: Troubleshooting Guide
8 | 96% AFUE Gas Furnace Troubleshooting Guide No Light and No Fan (System Does Not Start Normally) Figures & Tables 1. Check for 18-31Vac power between these 2 terminals with multi-meter. Figure 3 1. Check for 115Vac power supply between L1 and common terminal Figure 1 1.
Page 9 Troubleshooting Guide 96% AFUE Gas Furnace | 9 1. Check for 18-31Vac power between “W/W1” & “C” terminals with multi-meter 1. Check for 18-31Vac power between Hi-heat/lo-heat/hi-cool/lo-cool and COM with multi-meter Figure 5 2. Check for 115Vac power supply between CIRC-H and N with multi-meter Figure 7 BLACK...
Page 10: E7 System Lock-Out Due To Failed Ignition E8 System Lock-Out Due To Too Many Flame Dropouts
1 0 | 96% AFUE Gas Furnace Troubleshooting Guide 3.2 E7 (System Lock-Out due to Failed Ignition) E8 (System Lock-Out due to too Many Flame Dropouts) Troubleshooting Chart Start Correct wiring Are there any according to loose wires or wrong wiring diagram connections? Does the...
Page 11 Troubleshooting Guide 96% AFUE Gas Furnace | 11 E7 (System Lock-Out due to Failed Ignition) E8 (System Lock-Out due to too Many Flame Dropouts) Figures & Tables 1. Check for 9-17 between these two terminals with multi-meter. 1. Check for 18-31Vac power between “M/HI”&”C” terminals with a multi-meter Figure 9 Figure 11...
Page 12: E1 Low Fire Pressure Switch Stuck Closed
1 2 | 96% AFUE Gas Furnace Troubleshooting Guide 3.3 E1 (Low Fire Pressure Switch Stuck Closed) Troubleshooting Chart Start Correct wiring Are there any according to loose wires or wrong the wiring connections? diagram Does the resistance of low fire Replace the pressure switch show pressure...
Page 13 Troubleshooting Guide 96% AFUE Gas Furnace | 13 E1 (Low Fire Pressure Switch Stuck Closed) Figures High fire pressure switch Low fire pressure switch Overflow pressure switch Figure 13 1. Check for ∞ resistance between these two terminals with multi-meter. Figure 14 Data subject to change...
Page 14: E2 Low Pressure Switch Stuck Open
1 4 | 96% AFUE Gas Furnace Troubleshooting Guide 3.4 E2 (Low Pressure Switch Stuck Open) E4 (Pressure Switch Cycle Lockout) E3 (High Pressure Switch Stuck Open) Troubleshooting Chart Start Correct wiring Are there any according to loose wires or wrong the wiring connections? diagram...
Page 15: Figure 17
Troubleshooting Guide 96% AFUE Gas Furnace | 15 E2 (Low Pressure Switch Stuck Open) E4 (Pressure Switch Cycle Lockout) E3 (High Pressure Switch Stuck Open) Figures The pressure switch that you are checking in this step depends on the number of LED ﬂ ashes. Refer to the speciﬁ c ﬂ ashes and their descriptions above.
Page 16: E5 Limit/Rollout Switch Open Less Than 5 Mins E6 Limit/Rollout Switch Open More Than 5 Mins
1 6 | 96% AFUE Gas Furnace Troubleshooting Guide 3.5 E5 (Limit/Rollout Switch Open Less than 5 Mins) E6 (Limit/Rollout Switch Open More than 5 Mins) Troubleshooting Chart Start “SW2” is used for the fan delay after burner starts. Correct wiring Are there any according to loose wires or wrong...
Page 17 Troubleshooting Guide 96% AFUE Gas Furnace | 17 E5 (Limit/Rollout Switch Open Less than 5 Mins) E6 (Limit/Rollout Switch Open More than 5 Mins) Figures & Tables 1. Rollout limit switch locations. Figure 21 1. Chamber mounted limit switch (behind the gas valve) 1 Chamber mounted limit switch (behind the gas valve) 2.
Page 18 1 8 | 96% AFUE Gas Furnace Troubleshooting Guide External static pressure (in. WC) Furnace Return-air Speed size inlet 1339 1327 1338 1309 1321 1320 1342 1334 1316 1335 Temp Rise-1st stage Temp Rise-2nd stage 37.3 37.7 37.5 38.3 38.1 38.1 37.6 37.9...
Page 19 Troubleshooting Guide 96% AFUE Gas Furnace | 19 External static pressure (in. WC) Furnace Return-air Speed size inlet 1752 1764 1768 1781 1774 1786 1762 1802 1792 1786 Temp Rise-1st stage 47.3 47.0 Temp Rise-2nd stage 47.5 47.3 47.3 47.0 47.7 46.8 47.2...
Page 20: Pr Incorrect Polarity Of
2 0 | 96% AFUE Gas Furnace Troubleshooting Guide 3.6 Pr (Incorrect Polarity of L1/L2) Troubleshooting Chart Start Correct the wire connection(black and white wire) according to wiring diagram. See Figure 23. Figures BLOWER DOOR SWITCH 115V FIELD- J-BOX SUPPLIED DISCONNECT TERMINAL BLOCK...
Page 21: Fl Low Flame
Troubleshooting Guide 96% AFUE Gas Furnace | 21 3.7 FL (Low Flame) Troubleshooting Chart Start Replace the gas Adjust the gas valve valve if the to ensure manifold pressure cannot gas pressure meets be adjusted the required values Is the Is the inlet gas manifold gas...
Page 22: Appendix A - Sequence Of Operation
2 2 | 96% AFUE Gas Furnace Troubleshooting Guide Appendix A - Sequence of Operation Two Stage Controller Logic A1. There are two heating modes: A1.1 Low Fire Heating Mode: Only W1 signal A1.2 High Fire Heating Mode: Both W1 and W2 signal If you are using a single stage thermostat, only a W1 signal will be sent.
Page 23: A1.1 Low Fire Heating Mode Logic (Only W1 Signal)
Troubleshooting Guide 96% AFUE Gas Furnace | 23 Heating Modes A1.1 Low Fire Heating Mode Logic (only W1 signal): Figure 24 When there is a call for heat (W1), the inducer will start on HIGH speed and the low pressure switch closes. This will last for 15s. Inducer will turn to low speed and ignitor will energize.
Page 24: A1.2 High Fire Heating Mode Logic (W1+W2 Signal)
2 4 | 96% AFUE Gas Furnace Troubleshooting Guide A1.2 High Fire Heating Mode Logic (W1+W2 Signal): Figure 25 When there is a call for heat (W1), the inducer will start on HIGH The blower motor will run at high speed for 30s for fan delay. speed and the low pressure switch closes.
Page 25 Troubleshooting Guide 96% AFUE Gas Furnace | 25 Ignition Failure and Reignition Sequence If the furnace fails to ignite, there is a separate logic for the re-ignition sequence: Figure 26 When there is a call for heat (W1), the inducer will start on HIGH speed and the low pressure switch closes.
Page 26: Requirements For Refrigerant Leakage Sensors
2 6 | 96% AFUE Gas Furnace Troubleshooting Guide Requirements for refrigerant leakage sensors W2 DELAY HEAT OFF DELAY COOL OFF DELAY DIP SW DIP SW DIP SW NOMINAL NOMINAL NOMINAL (MINUTES) (SECONDS) (SECONDS) S1-1 S1-2 S2-1 S2-2 S2-3 S2-4 *OFF *OFF *OFF...
Page 27 Requirements for refrigerant leakage sensors WARNING: According to the safety requirements of UL 60335-2-40 on combustible refrigerant A2L, when the gas furnace is used  with coil and the new type of combustible refrigerant is used in the coil, the unit must be equipped with the refrigerant gas detection sensor to monitor the refrigerant concentration around the unit in real time to prevent the danger of abnormal refrigerant leakage.
Page 29 说明书更改说明此页不做菲林技术要求：双胶纸100g，黑白印刷，210*297mm...