Heat pumps · Error codes · Midea
bAMidea · M-Thermal Arctic HT R290 monobloc (MHC ...WD2N7)
bA on a Midea M-Thermal Arctic HT R290 monobloc: T4 sensor out of operation range protection
Short answer
On a Midea heat pump, bA means: T4 sensor out of operation range protection. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: T4 sensor out of operation range protection.
Likely causes:
- See R290 service manual troubleshooting (section 6) for this code.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
What you can check
- Read and note the exact code shown on the controller display.
- Check the heat pump's breaker/isolator at the consumer unit is on.
- Restart once via the controller (OFF then ON) as the manual allows; if the code returns, call an engineer.
What the engineer will check
- See R290 service manual troubleshooting (section 6) for this code.
Sources
- R290 M thermal Arctic HT Series Service Manual ↗ · 2025-10-15 v5 (from file name) · page 92 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026