Heat pumps · Error codes · ESP
6ESP · Classic / Classic II fixed-speed air/water (PASRW-0x0B-KA/KD)
6 on an ESP Classic / Classic II fixed-speed air/water: High pressure (High pressure switch action)
Short answer
On an ESP heat pump, 6 means: High pressure (High pressure switch action). The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: High pressure (High pressure switch action).
Likely causes:
- High pressure switch action.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: yes (table "Recover: Yes").
What you can check
- Note the code and any text shown on the display/controller.
- Check the heat pump isolator and consumer-unit breaker are on.
What the engineer will check
- Check through the pressure switch and system.
Who to ask for: heat pump engineer.
Certification: F-gas certified engineer (refrigerant circuit).
Sources
- ESP Classic II 13kW, 15kW, 17kW & 25kW Air Source Heat Pump - Installation & Operation Manual V2.3 (PASRW-040B-KA/050B-KA/060B-KA/080B-KA/080SB-KA) ↗ · V 2.3 · page 39-40 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026