10 blinks, 2.5 s OFFMitsubishi Electric · MSZ / MSY / MUZ / MUY GL NA series · Mini Split

Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series error code 10 blinks, 2.5 s OFF

Discharge temperature too low, starved compressor

Needs attention soon

Also written as ten blinks, 10, low discharge temperature, starved, 122F

Quick answer

On Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series, 10 blinks, 2.5 s OFF is a fault. It means discharge temperature too low, starved compressor. A first thing to check: A refrigerant leak that has reduced the charge.

Applies to: Mitsubishi Electric MSZ / MSY / MUZ / MUY GL NA series; Mitsubishi Electric MR SLIM GL series split codes · Mini Split
Type of code: Fault; Urgency: Needs attention soon
First safe check: Inspect the refrigerant lines for oil staining or a frost patch, which is where a leak shows first.

Checked 2026-09-26

What 10 blinks, 2.5 s OFF means on this model

The opposite of five blinks, and usually a leak. The condition is a discharge temperature thermistor reading of 122 F, which is 50 C, or less, continuously for twenty minutes. A compressor that cannot get its discharge hot is not getting enough refrigerant, and the manual points at the electronic expansion valve and the refrigerant circuit and amount.

Symptoms you will notice

Upper lamp blinks ten times after a three second hold, no beep
The system runs for a while then stops
The discharge pipe is cool rather than hot
The system never reaches set temperature in either mode

Common causes

The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:

A refrigerant leak that has reduced the charge
An incorrect charge from installation
An electronic expansion valve that is not feeding the compressor, starving it
A restricted refrigerant circuit
A failed discharge temperature thermistor reading falsely low

What you can safely check

These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.

Inspect the refrigerant lines for oil staining or a frost patch, which is where a leak shows first.
Check that the system is not simply undercharged from the original installation rather than having leaked.
Check the discharge temperature thermistor resistance before assuming the charge is the problem.

Do not do these

×Do not add refrigerant without finding the leak. On a leaking system the refrigerant ends up in the atmosphere and the fault returns.
×Do not keep restarting. A starved compressor has no refrigerant to cool its windings, which is exactly what destroys it.
×Do not work on the refrigerant circuit without recovery equipment and the factory procedures.

When to call a technician

Book a technician, do not keep resetting it

This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.

The refrigerant circuit is sealed and legally requires licensed handling. Opening it without certification releases refrigerant and can put the whole system in violation of regulation, so a low-pressure or high-pressure fault on this equipment is a call-out, not a weekend job.
If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.

A licensed technician job. Looking for oil staining on the piping is reasonable for a homeowner.

What it costs to fix

Parts

Refrigerant by the pound $40 to $120. Electronic expansion valve $200 to $500. Discharge temperature thermistor $30 to $90.

Labor

Two to five hours to find the leak, recover and recharge.

DIY or technician