Midea MSH-21HRN1-QB8 Service Manual

[Page 1] Midea MSH-21HRN1-QB8

Cover Service manual Service manualService manual Service manual Room airconditioner Room airconditionerRoom airconditioner Room airconditioner Split Wall mounted Type Split Wall mounted TypeSplit Wall mounted Type Split Wall m...

[Page 2] Midea MSH-21HRN1-QB8

Content 2 Content 1. Precaution...........................................................................................................................................2 1.1 Safety Precaution.......................................

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Content 3 10. Troubleshooting...............................................................................................................................27 10.1 Display board ...............................................................

[Page 4] Midea MSH-21HRN1-QB8

Service manual 2 1. Precaution 1.1 Safety Precaution  To prevent injury to the user or other people and property damage, the following instructions must be followed.  Incorrect operation due to ignoring instruction will cause harm or...

[Page 5] Midea MSH-21HRN1-QB8

Service manual 2 electric shock.  Do not open the inlet grill of the product during operation. (Do not touch the electrostatic filter, if the unit is so equipped.) There is risk of physical injury, electric shock, or product failure. ...

[Page 6] Midea MSH-21HRN1-QB8

Service manual 3 2. Function The function will be operate in any operation mode. Indoor unit Operation ON/OFF by remote controller Room temperature sensor. Pipe temperature sensor. Sensing by room temperature Indoor fan...

[Page 7] Midea MSH-21HRN1-QB8

Service manual 4 The unit has 3 mins delay between continuously ON/OFF operations. Outdoor unit Power relay control Bird tail propeller fan makes the outdoor unit run more quietly. Low noise air flow system The hydrophilic fin ca...

[Page 8] Midea MSH-21HRN1-QB8

Service manual 5 3. Dimension 3.1 Indoor unit Dimension Mode W H D 21K 1030 313 221 24K 1030 313 221 3.2 Outdoor unit Dimension Mode W H D L1 L2 L3 21K 845 695 335 560 360 560 24K 845 695 335 56...

[Page 9] Midea MSH-21HRN1-QB8

Service manual 6 Specification： MSH-21HRN1-QB8 MSH-24HRN1-QB8 Ph-V-Hz 1, 220-240V~, 50Hz 1, 220-230V~, 50Hz Capacity Btu/h 21000 24000 Input W 2150 2450 Rated current A 9,3 10,7 EER Btu/w.h 9.8,2.86...

[Page 10] Midea MSH-21HRN1-QB8

Service manual 7 4. Refrigerant cycle diagram  Cooling only  Heat pump mode ...

[Page 11] Midea MSH-21HRN1-QB8

Service manual 8 5. Operation limits 5.1 Cooling operation Outdoor unit air temp.℃ DB Indoor air temp. ℃ DB Note: The chart is the result from the continuous operation under constant air temperature conditions. However, excludes ...

[Page 12] Midea MSH-21HRN1-QB8

Service manual 9 6. Wiring diagram Indoor： Outdoor： ...

[Page 13] Midea MSH-21HRN1-QB8

Service manual 10 7. Installation details 7.1 Wrench torque sheet for installation Outside diameter Torque mm inch Kg.m φ9.52 3/8 4.2 φ12.7 1/2 5.5 φ15.88 5/8 6.6 7.2 Connecting the cables The power cord of connect shou...

[Page 14] Midea MSH-21HRN1-QB8

Service manual 11 7.4 Air purging of the piping and indoor unit Required tools: Hexagonal wrench; adjustable wrench; torque wrenches, wrench to hold the joints and gas leak detector. Note: The air in the indoor unit and in the piping must b...

[Page 15] Midea MSH-21HRN1-QB8

Service manual 12 7.5 Pumping down (Re-installation) Procedure Confirm that both the 2-way and 3-way valves are set to the opened position. Remove the valve stem caps and confirm that the valve stems are in the opened position. Be sure ...

[Page 16] Midea MSH-21HRN1-QB8

Service manual 13 7.6 Re-air purging (Re-installation) Procedure: Confirm that both the 2-way and 3-way valves are set to the closed position. Connect the charge set and a charging cylinder to the service port of the 3-way valve. Leave th...

[Page 17] Midea MSH-21HRN1-QB8

Service manual 14 7.7 Balance refrigerant of the 2-way, 3-way valves Procedure: Confirm that both the 2-way and 3-way valves are set to the open position. Connect the charge set to the 3-way valve’s service port. Leave the valve on the ...

[Page 18] Midea MSH-21HRN1-QB8

Service manual 15 7.8 Evacuation Procedure: Connect the vacuum pump to the charge set’s centre hose. Evacuation for approximately one hour. Confirm that the gauge needle has moved toward -0.1 Mpa (-76 cmHg) [vacuum of 4 mmHg or less]. ...

[Page 19] Midea MSH-21HRN1-QB8

Service manual 16 7.9 Gas charging Procedure: 1. Connect the charge hose to the charging cylinder.  Connect the charge hose which you disconnected from the vacuum pump to the valve at the bottom of the cylinder. 2. Purge the air fro...

[Page 20] Midea MSH-21HRN1-QB8

Service manual 17 8. Electronic function 8.1 Electronic control working environment Input voltage: 175~253V or 100~130V Input power frequency: 60Hz Ambient temperature: -7°C+43°C Indoor fan normal working amp is less than 1A Outdoor fa...

[Page 21] Midea MSH-21HRN1-QB8

Service manual 18 8.4 Protection 8.4.1 3 minutes delay at restart for compressor. 8.4.2 Sensor protection at open circuit and breaking disconnection 8.4.3 Fan Speed is out of control. When Indoor Fan Speed is too high(higher than High ...

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Service manual 19 ...

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Service manual 20 Auto fan at cooling mode: 4 T-Ts Room temp. up Room temp. down 5 High fan Low fan 1 Mid. fan Anti-freezing control to indoor evaporator at cooling mode ( T: evaporator temp. ) TE5 T EVAP. temp. up EVAP. temp. down TE6 Comp...

[Page 24] Midea MSH-21HRN1-QB8

Service manual 21 8.8.3 Action of compressor and outdoor fan motor at heating mode: compressor must run for 7 minutes after starting and then judge temperature. Meanwhile other protections are still valid. Ts+2* T Room temp. up Room temp. down ...

[Page 25] Midea MSH-21HRN1-QB8

Service manual 22 T T temp. up T temp. down TE7 Compressor on Fan on TE8 TE9 Compressor off Fan off Compressor on Fan off The louver opens to Standard Angle ANGLHEAT when power is on for the first time 8.9 Defrosting mode(available for heati...

[Page 26] Midea MSH-21HRN1-QB8

Service manual 23 -1 TA-TS 2 Heating (fan only at cooling) Fan only Cooling 8.10.2 The indoor fan blows automatically in corresponding selected mode； 8.10.3 The motion of indoor fan’s blade should accord with the selected operation mode；...

[Page 27] Midea MSH-21HRN1-QB8

Service manual 24 The set temperature decrease 1℃ per hour. Two hours later, the set temperature will maintain as a constant and the air circulation is kept at low speed (Anti-cold function takes precedence over all). Time Room temperature 2 ...

[Page 28] Midea MSH-21HRN1-QB8

Service manual 25 9. Model and Parameters Model MSR1-21HRN1-QB8 MSR1-24HRN1-QB8 I3SEC 14A 18A I5MIN 20A 24A IFAN 22A 26A TE1 25℃ 25℃ TE2 32℃ 32℃ TE3 30℃ 30℃ TE4 20℃ 20℃ TE5 2℃ 2℃ TE6 12�...

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Service manual 26 10. Troubleshooting 10.1 Display board  Operation The indicator flashes once every second after power is on and illuminates when the air conditioner is in operation.  Timer indicator: The indicator illumin...

[Page 30] Midea MSH-21HRN1-QB8

Service manual 27 10.3 Diagnostic chart After energizing, no indicator is lighted and the air conditioner can’t be operated. After energizing , the air conditioner can not be operated . Check if AC 220V power supply outputs to indoor PC...

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Service manual 28 10.4 Resetting phenomenon often occurs during operation. (That is automatically entering to the status when power is on.) The reason is that the instantaneous voltage of main chip is less than 4.5V. Check according to the...

[Page 32] Midea MSH-21HRN1-QB8

Service manual 29 10.6 Temperature sensor error. Including the indoor room, indoor evaporator and outdoor condenser temperature sensor. Is connector connection good ? Replace the sencor, No Repair the connector . 10.7 Outdoor unit...

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Service manual 30 11. Characteristic of temperature sensor Temp. ℃ Resistance K Ω Temp. ℃ Resistance K Ω Temp. ℃ Resistance K Ω -10 62.2756 17 14.6181 44 4.3874 -9 58.7079 18 13.918 45 4.2126 -8 56.369...