Heat pumps · Error codes · Dimplex
BLK-DefDimplex · WPM heat pump manager platform (error-code grouping)
BLK-Def on a Dimplex WPM heat pump manager platform: Heat pump blocked: with 'measure defrost' active the usual lowering of the flow temperature during defrosting did not occur
Short answer
On a Dimplex heat pump, BLK-Def means: Heat pump blocked: with 'measure defrost' active the usual lowering of the flow temperature during defrosting did not occur. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Heat pump blocked: with 'measure defrost' active the usual lowering of the flow temperature during defrosting did not occur.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: Automatic when condition clears.
What you can check
- Note the fault code, the heat pump model (type plate) and controller software version shown in operating data, and contact the installer/Dimplex service.
What the engineer will check
- Investigate cause (flow rate / refrigerant pressure / wiring bridge A1).
What you might notice
Sources
- Dimplex WPM EconPlus / WPM EconR heat pump manager - Operating instructions for users (Order no. 452114.66.57, FD 8902) ↗ · 452114.66.57 FD 8902 · page EN-14 (ManualsLib p.36) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026