Hisense mini split error code 33

Common causes

• The indoor room temperature thermistor has failed (they do drift and fail with age and heat cycling).
• Its plug has worked loose from the control board, or a pin has corroded.
• The sensor lead is chafed, pinched or chewed, giving an intermittent open or short.
• The control board's sensor input has failed (rare compared with the sensor itself).

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
2. If the code comes straight back after a reset, the fault is real and not a glitch.
3. With power off, locate the indoor room temperature sensor behind the front panel near the air inlet. Follow its lead back to the board and reseat the plug firmly.
4. Inspect the lead for damage along its whole length, especially where it passes through the chassis.
5. If you have a multimeter, unplug the sensor and measure its resistance. A reading near zero ohms (short) or infinite (open) confirms a bad sensor. Most mini split thermistors read roughly 5 to 20 kΩ at room temperature, so a value in that range with a steady drift as you warm it in your hand means the sensor is fine and the board is the suspect.
6. Replacement thermistors are inexpensive and plug in. Match the part number from the parts list for your model.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Sensor swaps are a doable DIY job on most units. Call a technician if the sensor tests good and the code persists, because that points at the control board.

Which Hisense units show 33

This page applies to Hisense Hisense inverter single-zone and Hisense multi-zone units. Hisense's own documentation lists 33 as "Indoor room temperature sensor fault (open or short circuit)", the same definition used across the Hisense it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where Hisense shows this code

Hisense inverter splits store the fault as a number. When the compressor has stopped on a fault, point the remote at the unit and press the SLEEP button 10 times within 10 seconds: the indoor display then shows the code (a second stored fault shows after four more presses). The Sleep, Timer and Running lamps also blink a pattern that matches the code. Newer models show the number on the display without the button sequence. Codes 1 to 21 are outdoor-unit faults and protections; 33 to 41 are indoor-unit faults. 0 means no fault is stored.

Other Hisense codes

Same part of the system as 33:

All Hisense error codes

33 on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

• Haier 33 Zone B indoor unit gas pipe temperature sensor fault (open or short circuit)