Mini-Split Support Center

Troubleshooting: No Heat / Blowing Cold Air

• Check the mode: Ensure the remote is set to HEAT mode (sun icon), not AUTO or COOL
• Set temperature correctly: Set temperature higher than room temperature (at least 3-5° above)
• Wait for defrost cycle: In cold weather, the outdoor unit may run a defrost cycle for 5-10 minutes
• Check outdoor unit: Verify the outdoor unit fan is spinning and compressor is running
• Touch the line set: In heat mode, the suction line (larger) should feel warm, and the liquid line (smaller) should be hot. If both are cold, system may be low on refrigerant or have a reversing valve issue
• Verify refrigerant pressure: In heat mode, PSI should read 400-450 PSI

Troubleshooting: Blower Shuts Off Immediately in Heat Mode

• Low refrigerant: This is the most common cause. In heat mode, the indoor coil must reach a certain temperature before the blower will run
• Check error code 13: If you see E13, the refrigerant level is likely too low to heat the coil properly
• Touch the outdoor lines: If the suction line (larger line) feels cool or just slightly warm, and the liquid line (smaller line) is not hot, the system is likely low on charge
• Unit may cool fine: It's common for a unit to work in cooling mode but fail in heating mode due to low refrigerant
• Have a technician check: Locate and repair any refrigerant leak, then evacuate and recharge the system to factory specifications

Troubleshooting: Unit Cools But Won't Heat

• Check reversing valve: The reversing valve switches between cooling and heating - it may be stuck or faulty
• Both lines cold in heat mode? If both suction and liquid lines are cold, the system pressures are likely balanced, suggesting a failed reversing valve (stuck in cooling position or leaking internally)
• Low refrigerant: Your unit can cool properly but fail to heat due to insufficient refrigerant
• Verify wiring: Ensure all wire connections between indoor and outdoor units are secure
• Check outdoor temperature: Heat pumps are less efficient below 40°F - some units have minimum operating temps
• Listen for click: When switching to heat, you should hear a "click" from the reversing valve

Heat Pump Freezing in Cold Weather (Below 40°F)

• Normal operation: Heat pumps become less efficient as outdoor temperatures drop, especially below 40°F
• Defrost cycle is normal: The outdoor unit will periodically run in reverse to melt accumulated ice/frost (takes 5-15 minutes)
• During defrost: Indoor fan may blow cool air or shut off temporarily - this is normal
• Check for low refrigerant: If unit struggles below 40°F, low refrigerant is the most common cause - unit needs more charge in cold temps
• Ice buildup on outdoor coil? Minor frost is normal, but heavy ice coating indicates airflow restriction or low charge
• Line set temperature check: In heat mode at 35-40°F outdoor temp, suction line (larger) should feel warm/hot and liquid line (smaller) should be very hot. If cool, refrigerant is low
• Minimum operating temperature: Most residential heat pumps have minimum operating temps (typically 5-15°F). Check your manual
• Consider backup heat: For consistent heating below 35°F, a backup heating source (electric or gas) is recommended

Error Code 19 E19 - Outdoor Control Board Fault

• Power cycle the unit: Turn off at breaker for 5 minutes, then restart
• Check for power surges: Control boards commonly fail due to electrical surges - install a surge protector
• Check for critters: Small animals (lizards, snakes, rodents) can get inside the outdoor unit and cause damage
• Inspect outdoor coils: Clean any debris, ice, or dirt from outdoor unit coils
• Verify voltage: Ensure proper voltage supply to outdoor unit (230V or 115V depending on model - check nameplate)
• Check compressor: If compressor isn't starting, the capacitor or compressor itself may be faulty

Troubleshooting: Compressor Not Running

• Check power supply: Verify proper voltage at outdoor unit disconnect (230V or 115V depending on model - check nameplate)
• Listen for sounds: Humming = possible bad capacitor. Clicking = possible relay issue
• Check for error codes: Note any codes on indoor display (E19 is common)
• Check LED lights: Remove outdoor unit top panel and observe LED pattern on control board
• Inspect control board: If the board shows signs of damage (burn marks, bulging components), the entire board needs replacement
• Verify thermostat demand: Indoor unit must be calling for heat/cool
• Check overload protection: Compressor may have thermal overload - let it cool down 30 minutes
• Compressor shorted? If a technician finds the compressor shorted to ground on all terminals, the compressor has failed and needs replacement

Troubleshooting: Cooling Issues

• Check mode setting: Ensure unit is in COOL mode (snowflake icon)
• Set temperature lower: Temperature must be set below current room temp
• Clean filters: Dirty filters drastically reduce cooling capacity
• Check outdoor unit: Ensure outdoor coils are clean and fan is running
• Verify refrigerant: Low refrigerant causes poor cooling - check for leaks
• Check airflow: Ensure vents aren't blocked and louvers are open

Troubleshooting: Remote Control Issues

Unit not responding to remote or settings "locked"

• Check for beep: If you hear a beep when pressing buttons, the unit is receiving the signal - remote is working
• Replace batteries: Weak batteries are the most common cause - replace with fresh AAA batteries
• Check battery polarity: Ensure batteries are installed with correct +/- orientation
• Unit locked? Some remotes have a lock function - check for a lock icon on display
• Remote sensor blocked? Ensure nothing is blocking the sensor on the indoor unit
• Distance test: Try operating from different distances and angles
• Power cycle unit: Turn off at breaker for 5 minutes to reset any software glitches
• Test with different remote: If available, try another compatible remote to isolate the issue
• Settings won't change: If unit blows air but won't respond to temperature/mode changes, the remote may need replacement

Troubleshooting: Unit Tripping Breaker

Unit has power but won't turn on, or trips breaker when starting

• Verify voltage supply: Unit requires 230V or 115V depending on model - have an electrician test voltage at the disconnect box and compare to nameplate
• Check breaker size: Ensure breaker is properly sized for your unit (typically 15-20A for residential units)
• Test L1-L2 voltage: Should read approximately 230V between L1 and L2 for 230V models, or 115V for 115V models
• Test neutral-line voltage: For 230V models, check voltage between Neutral and each line (L1 and L2) - should read ~115V each. For 115V models, verify 115V at the supply
• Inspect wiring connections: Look for loose, corroded, or overheating connections at both units
• Check for short circuit: A short in wiring or components will trip breaker immediately
• Damaged compressor: A shorted compressor will trip breaker on startup
• Failed control board: Indoor unit electrical failure can prevent power-up
• Extreme cold conditions: Units may struggle to start in polar vortex conditions (below -10°F)

Error Code 6 E6 - Voltage/Electrical Issue

• Check voltage supply: Unit requires 230V or 115V depending on model - verify with multimeter against nameplate rating
• Inspect wiring: Look for loose or damaged wire connections - connections may be loose or wired incorrectly
• Check breaker: Ensure dedicated breaker is properly sized (230V or 115V depending on model)
• Verify neutral/ground: Proper grounding is essential for operation
• Check wire gauge: Ensure proper gauge wire for the distance run - refer to nameplate on outdoor unit

Error Code 12 E12 - Outdoor Temperature Sensor Issue

LED Pattern: Solid / Blinking / Blinking

• Primary causes: Outdoor temperature sensor dirty, faulty, or ambient temperature too cold to operate
• DIY Fix - Clean the sensor: Locate the small black tube on the top corner of the outdoor coil
• Cleaning procedure: Gently wash the sensor with warm water to remove dirt, debris, or frost buildup
• Test after cleaning: Power cycle the unit (off at breaker for 5 minutes) and restart
• Too cold to operate? E12 can appear if outdoor temperature is below the unit's minimum operating range (typically 5-15°F for heating)
• Check service valve caps: Missing caps can cause slow refrigerant leaks, which may trigger this error
• Low refrigerant connection: This error can also indicate low refrigerant - check line temperatures
• Sensor replacement: If cleaning doesn't resolve the issue, the outdoor temperature sensor may need replacement

Error Code 13 E13 - Low Refrigerant / Temperature Issue

• Low refrigerant: This error typically indicates the refrigerant level is too low to heat the indoor coil to the required temperature
• Blower won't run in heat: The indoor blower fan won't trigger if the coil can't reach a certain temperature
• Touch the outdoor lines: In heat mode, lines should feel warm/hot. If cool or just slightly warm, refrigerant is low
• AC may work fine: The unit may cool properly but fail in heating mode due to insufficient charge
• Have a tech check: Contact your local HVAC technician to refill refrigerant and check for leaks

Error Code 15 E15 - Temperature Sensor / Low Refrigerant

• Primary cause: Temperature sensor issue or low refrigerant charge
• Check line temperatures: Touch the outdoor lines - if suction line (larger) is cool/warm instead of hot, refrigerant is low
• Sensor failure: The outdoor coil temperature sensor may have failed or become disconnected
• Verify sensor connection: Check that the outdoor coil sensor is plugged into the control board
• Test sensor resistance: A technician can test the sensor with a multimeter (typical resistance: 5-50kΩ depending on temperature)
• Refrigerant leak check: If sensor is OK, have technician check for refrigerant leaks and recharge system
• Power cycle: Turn off at breaker for 5 minutes, then restart - if error returns immediately, likely sensor failure

Error Code 17 E17 - Indoor/Outdoor Communication Failure

• Communication failure: Error 17 indicates the indoor and outdoor units cannot communicate properly
• Symptom: Fan may blow briefly then stop, unit won't heat or cool
• Power cycle first: Turn off at breaker for 5 minutes, then restart
• Check communication wiring: Verify all wires between indoor and outdoor units are securely connected
• Inspect terminals: Look for loose, corroded, or damaged wire connections at both units
• Verify wiring order: Ensure wires are connected according to the wiring diagram (typically Ground, White, Black)
• Outdoor control board: If wiring is correct and error persists, the outdoor control board likely needs replacement
• Check for surge damage: Power surges are a common cause of board failure

Error Code 18 E18 - DC Compressor Start Failure

• Compressor won't start: The DC inverter compressor is failing to start or reach required speed
• Check power supply: Verify proper voltage at outdoor unit (230V or 115V depending on model) - low voltage can prevent compressor start
• Inspect control board: If the board shows signs of damage (burn marks, bulging components), the entire board needs replacement
• Check outdoor temperature: E18 can occur if outdoor temp is outside operating range (too cold or too hot)
• Refrigerant level: Low refrigerant can cause compressor to fail startup checks
• Outdoor control board: The board may not be sending proper signals to the compressor - may need replacement
• Compressor failure: If all else checks out, the compressor itself may have failed (shorted windings, seized mechanically)
• Power cycle test: Turn off at breaker for 10 minutes to allow compressor to cool, then restart

Error Code 36 E36 - Communication Failure

• Indoor/Outdoor communication: E36 indicates a communication failure between the indoor and outdoor units
• Check cable connections: Ensure all communication cables between units are securely connected
• Inspect wire terminals: Look for loose, damaged, or corroded connections at both units
• Verify wiring order: Check that wires are connected in the correct order per the wiring diagram (Ground, White, Black)
• Check outdoor LED lights: If outdoor LEDs don't light up at all, the outdoor board may be damaged
• Power cycle: Turn off at breaker for 5 minutes, check all connections, then restart

Error Code 39 E39 - Indoor Fan Motor Issue

• Check for obstructions: Make sure nothing is blocking the indoor fan motor
• Check fan motor connection: Verify the fan motor cord is securely connected to the indoor board
• Test the fan motor: If connections are good and there's no blockage, the fan motor may have failed
• Indoor control board: If the fan motor is functional, the indoor control board may need replacement
• Get a tech report: A technician can verify whether the motor or board needs replacement

Other Error Codes

Common additional codes include E14, E16, E34, E74, and E77. For these codes:

• Document the code: Note the exact error code displayed
• Power cycle first: Turn off at breaker for 5 minutes, then restart
• Check your manual: Error code meanings are listed in your unit's documentation
• Get both codes: Check the indoor display AND the outdoor LED pattern
• Multiple codes: If seeing multiple codes (e.g., 16, 19, 77, 74, 34), contact support with all codes

Vacuum & Refrigerant Line Setup

• Yes, you need to vacuum: All air and moisture must be evacuated from lines before releasing refrigerant
• 3/8" to 1/4" adapter required: Most units have 3/8" service valves, but standard vacuum hoses are 1/4" - you'll need a "3/8" Female SAE × 1/4" Male SAE adapter" available at HVAC supply stores or online
• Use a vacuum pump: Pull vacuum to at least 500 microns (lower is better)
• Hold vacuum test: System should hold vacuum for 15-30 minutes without rising
• Vacuum rising quickly? Indicates a leak - check all flare connections
• Check service valve caps: Before starting, verify all service valve caps are present and tight - missing caps cause slow refrigerant leaks
• After vacuum: Open service valves slowly to release refrigerant into lines
• Replace caps after vacuum: Ensure all service valve caps are reinstalled after releasing refrigerant
• Line set shortening: There is no minimum line set length - just coil any excess

Mounting & Placement Guidelines

• Indoor unit height: Mount 7-8 feet from floor, at least 6 inches from ceiling
• Wall clearance: Minimum 4-6 inches from side walls for proper airflow
• Outdoor unit: Place on level surface, 12+ inches from walls
• Line set routing: Keep lines as short as possible, avoid kinks
• Drainage: Indoor unit must have proper condensate drain slope

Wiring & Electrical Setup

• Power requirement: Units require either 230V or 115V dedicated circuit depending on model - check the nameplate on the outdoor unit
• Power cable (breaker to unit): The power cable from the breaker to the unit has 3 wires: green, white, and black
• Communication cable (connects the 2 units): The communication cable that connects the indoor and outdoor units together has 4 wires: white, black, red, and green
• Proper wire gauge: Check the nameplate on the outdoor unit for required wire gauge
• Control board: Outdoor control boards come pre-programmed - no additional programming needed
• Ground wire: Always connect ground wire for safety

Installation Component Checklist & Missing Parts

Before starting installation, verify you have ALL these components. Missing parts are a common installation delay!

Indoor Unit Package Should Include:

• Indoor air handler unit with mounting plate
• Remote control with batteries
• Indoor unit mounting hardware (screws, anchors)
• Drain tubing for condensate
• Owner's manual and installation instructions

Outdoor Unit Package Should Include:

• Outdoor condenser unit
• Outdoor mounting brackets or pad (depending on model)
• Service port caps (often pre-installed on unit)
• Installation manual

Typically NOT Included (Sold Separately):

• Refrigerant line set - Must purchase separately (ensure correct size and length for your model)
• Communication/control wire (14/4 or 16/4 stranded) between indoor/outdoor units
• Power wire from breaker panel to outdoor unit (consult electrician for proper gauge)
• Disconnect box for outdoor unit (required by code)
• Wall penetration kit (wall sleeves, escutcheon plates)
• Condensate drain pump (if needed for your installation)

Leak & Refrigerant Issues

• Indoor coil leaking water? Check condensate drain for clogs, verify unit is level
• Outdoor unit leaking refrigerant? Look for oily residue around connections - this indicates refrigerant leak
• Oil in the condenser base? This is a sign of refrigerant leak - the oil residue comes from the refrigerant
• Ice forming on lines? Often indicates low refrigerant or airflow restriction
• Check flare connections: Most leaks occur at indoor/outdoor unit flare connections. Use soapy water to identify bubbling
• Flare won't tighten? If the flare is as tight as possible but still leaks, the flare fitting may be damaged
• Compressor area leak? May require compressor or unit replacement under warranty

Parts & Warranty Information

• Parts warranty: Replacement parts are covered for 1 year from proof of purchase or installation date
• Compressor warranty: The compressor is covered for up to 7 years
• Indoor unit coil warranty: The indoor unit has a 2-year warranty on the coils when any leaks occur
• DIY installations: Warranty starts 3 months after manufacturing date if no proof of purchase
• Labor NOT covered: Our warranty does NOT cover labor or services provided by technicians, electricians, or HVAC professionals
• Surge protector required: Replacement boards that fail due to power surges without surge protection are NOT covered
• For warranty claims: You'll need proof of purchase, model number, serial number, batch number (K-XXXX), photos of issue, and for major components - a technician's diagnosis report