Heat pumps · Error codes · Hisense
18Hisense · Hi-Therma Monobloc (R32)
18 on a Hisense Hi-Therma Monobloc: Water Pressure Sensor (Pw) Abnormality
Short answer
On a Hisense heat pump, 18 means: Water Pressure Sensor (Pw) Abnormality. 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: Water Pressure Sensor (Pw) Abnormality.
Part involved: temperature/pressure sensor.
Likely causes:
- Incorrect Wiring.
- Disconnecting Wiring.
- Breaking Wire.
- Short Circuit.
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: unknown.
What you can check
- Note the code shown on the controller and the unit model numbers (on the rating plate label) before contacting your installer.
- Check the heat pump's breaker/isolator at the consumer unit is on; do not open any casing.
- Check the controller display is lit; a single power cycle at the isolator may be tried only if your installer or manual allows it.
What the engineer will check
- Follow the handbook alarm-code flowchart (O.U. section from printed p.335, I.U. section from viewer p.383).
- Check sensor connector and wiring.
- Measure sensor resistance against the manual's sensor table.
- Replace sensor or PCB as indicated by the troubleshooting flowchart.
Who to ask for: Heat pump engineer.
Certification: Heat pump installer competence; F-gas / flammable-refrigerant (R290/R32) handling competence for any refrigerant-circuit work.
What you might notice
Sources
- Air-to-Water Heat Pump Technical, Installation and Service Handbook - Hi-Therma Series (TCY12021017E) ↗ · TCY12021017E · page p.333 (printed; ManualsLib viewer p.354) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026