Heat pumps · Error codes · Danfoss
hgw-sensorDanfoss · DHP-AQ
hgw-sensor on a Danfoss DHP-AQ: Sensor fault alternatively cable fault
Short answer
On a Danfoss heat pump, hgw-sensor means: Sensor fault alternatively cable fault. 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: Sensor fault alternatively cable fault.
Part involved: HGW (hot gas) sensor.
Likely causes:
- Sensor or cable fault.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: Yes, when the condition clears (inferred).
What you can check
- Note the exact alarm text. The manual allows acknowledging by setting operating mode OFF then back once; if the alarm returns, call an engineer.
What the engineer will check
- Disconnect the sensor and measure resistance with and without its cable against the ohm table in 'Measurement points' (section 3.3); replace the sensor if out of tolerance, otherwise the cable.
Who to ask for: heat pump engineer.
What you might notice
Sources
- Service Instructions DHP-AQ (VMGFJ202) ↗ · VMGFJ202 · page p.10; p.18 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026