Er240 on an Ochsner OTE 3 / OTE 4 controller fault platform: OTE does not detect a Modbus PCB. Cause/remedy per manual: Contact OCHSNER Customer Service
Short answer
On an Ochsner heat pump, Er240 means: OTE does not detect a Modbus PCB. Cause/remedy per manual: Contact OCHSNER Customer Service. 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: OTE does not detect a Modbus PCB. Cause/remedy per manual: Contact OCHSNER Customer Service.
Part involved: OTE does not detect a Modbus PCB.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: Heat pump restarts automatically when the safety assembly re-enables it; 2 automatic acknowledgements allowed (manual 17.2).
Manual reset: Up to 3 manual acknowledgements via ESC > ERROR menu > setting button (manual 17.2.1).
What you can check
- Note the Er number and text (ESC on main screen opens the alarm menu) and contact your OCHSNER system partner.
- The manual allows the user to try acknowledging an ERROR once via the ESC menu; if it returns, leave it and call the installer.
What the engineer will check
- Contact OCHSNER Customer Service.
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 53 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026