Heat pumps · Error codes · York
PbYork · YKF Mono (CNC/CRC, 5-16 kW, R32)
Pb on a York YKF Mono: Anti-freeze mode
Short answer
On a York heat pump, Pb means: Anti-freeze mode. The manual does not say whether the heat pump stops.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Anti-freeze mode.
Likely causes:
- Cause/corrective action column not provided in this YORK manual table; see Midea M-Thermal service documentation for the equivalent code (not copied here).
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The manual does not say whether the heat pump stops.
What you can check
- Read the display; this is a protection/indication state and the manual says the unit returns to normal automatically.
- Keep the heat pump powered in cold weather so frost protection can run.
What the engineer will check
- Cause/corrective action column not provided in this YORK manual table; see Midea M-Thermal service documentation for the equivalent code (not copied here).
Sources
- YKF Air Source Heat Pump System - Monoblock Single and Triphase, 5 kW to 16 kW - Installation, Commissioning, Operation and Maintenance, Form 201.55-ICOM1.EN.CE (622) ↗ · 201.55-ICOM1.EN.CE (622) · page PDF 60 (printed 57) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026