Heat pumps · Error codes · Midea
HbMidea
Hb on a Midea heat pump: PP occurs 3 times in heating/DHW mode
Short answer
On a Midea heat pump, Hb means: PP occurs 3 times in heating/DHW mode. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 3 sources
What it means
On the M-Thermal Arctic HT R290 monobloc (MHC ...WD2N7)
The manual says: PP occurs 3 times in heating/DHW mode.
Likely causes:
- See R290 service manual troubleshooting (section 6) for this code.
On the M-Thermal Mono R32 (MHC ...W/D2N8-B / -B2 'Arctic')
The manual says: PP error occurred 3 times (stated in PP troubleshooting section).
Likely causes:
- See service manual troubleshooting procedure for this code.
On the M-Thermal Split R32 (MHA outdoor + HB hydronic box)
The manual says: PP protection appears three times in a row and Tw_out < 7 C.
Likely causes:
- See service manual troubleshooting procedure for this code.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Severity | Safety lockout |
| 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.
- Read the system pressure gauge and report the reading to your engineer (manuals ask for more than 1 bar when cold).
- Check the filling loop valves are closed.
- Restart once via the controller (OFF then ON) as the manual allows; if the code returns, call an engineer.
What the engineer will check
On the M-Thermal Arctic HT R290 monobloc (MHC ...WD2N7)
- See R290 service manual troubleshooting (section 6) for this code.
On the M-Thermal Mono R32 (MHC ...W/D2N8-B / -B2 'Arctic')
- See service manual troubleshooting procedure for this code.
On the M-Thermal Split R32 (MHA outdoor + HB hydronic box)
- See service manual troubleshooting procedure 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
- Midea M thermal Arctic Mono (4~16kW) Service Manual ↗ · not stated (MBT Confidential) · page 122 · Reviewed 23 September 2026
- M-Thermal A Series Split R32 Service Manual (Midea CAC, 202004) ↗ · 202004 (file v31) · page 50 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026