12 on an Ecoforest heat pump: Failure of any indoor th-Tune ambient terminal (defective terminal indicated on screen)
Short answer
On an Ecoforest heat pump, 12 means: Failure of any indoor th-Tune ambient terminal (defective terminal indicated on screen). The manual does not say whether the heat pump stops. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 2 sources
What it means
On the ecoGEO Basic & Compact (R410A inverter GSHP)
The manual says: Failure of any indoor th-Tune ambient terminal (defective terminal indicated on screen).
When it shows: Monitored parameter outside normal range: Failure of any indoor th-Tune ambient terminal (defective terminal indicated on screen).
On the ecoGEO HP (high power)
The manual says: Failure of a th-Tune indoor terminal (defective terminal shown).
When it shows: Monitored parameter outside normal range: Failure of a th-Tune indoor terminal (defective terminal shown).
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
Manual reset: User ALARM menu: Alarm reset -> Yes (2013 manual p60).
What you can check
- Read and note the alarm number/message shown on the heat pump front panel (Alarm button lights red).
- Check the heat pump supply breaker at the consumer unit is on.
- Reset active alarms via the user ALARM menu (Alarm reset -> Yes) as the user manual allows; if the alarm returns, call the installer/service centre.
- Check the th-Tune room terminal display is powered and showing readings.
What the engineer will check
- Check th-Tune terminal power/communication wiring.
- Consult Ecoforest technical service documentation (restricted portal).
Who to ask for: heat pump / heating engineer.
What you might notice
Sources
- ecoGEO B1/B2/B3 & C1/C2/C3 3-12 / 5-22 kW Installation and User Manual V03.B03_EN (23/09/2015) ↗ · V03.B03_EN · page 79 · Reviewed 23 September 2026
- ecoGEO HP Installation and Operating Manual Version 1.00 (08/05/2014) ↗ · 1.00 · page 54 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026