Er48 on an Ochsner OTE 3 / OTE 4 controller fault platform: TQE sensor/evaporator 1 faulty. Cause/remedy per manual: Replace sensor
Short answer
On an Ochsner heat pump, Er48 means: TQE sensor/evaporator 1 faulty. Cause/remedy per manual: Replace sensor. 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: TQE sensor/evaporator 1 faulty. Cause/remedy per manual: Replace sensor.
Part involved: TQE sensor/evaporator 1 faulty.
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: ALARM: substitute value used, heat pump continues in emergency mode.
What you can check
- Note the Er number and text (ESC on main screen opens the alarm menu) and contact your OCHSNER system partner.
What the engineer will check
- Replace sensor.
Who to ask for: OCHSNER customer service / authorised service partner (manual: ERROR faults only remedied by OCHSNER or authorised partners).
What you might notice
Sources
- OCHSNER OTE 3 / OTE 4 Controller manual (end customer), EN06 ↗ · EN06 (RA_982072) · page 52 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026