E152 on a CTC control system alarm/information platform: 4-way valve: fault with the EcoAir 4-way valve or EcoAir connection pipes connected wrongly; check the charge pump pumps to the heat pump lower connection
Short answer
On a CTC heat pump, E152 means: 4-way valve: fault with the EcoAir 4-way valve or EcoAir connection pipes connected wrongly; check the charge pump pumps to the heat pump lower connection. 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: 4-way valve: fault with the EcoAir 4-way valve or EcoAir connection pipes connected wrongly; check the charge pump pumps to the heat pump lower connection.
Part involved: 4-way reversing valve / EcoAir pipework.
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.
Manual reset: Press "Reset alarm" on the display; a persisting fault must be rectified before it can be reset.
What you can check
- If the manual instruction applies, press "Reset alarm" on the display once and note whether the alarm returns (manual: "Press reset and check whether the alarm recurs. If the fault recurs, contact your installer").
- Note the alarm code/text, the product model and serial number and contact your installer.
- Check the outdoor unit (air source) is not blocked by snow, leaves or debris.
What the engineer will check
- Check the charge pump pumps water to the heat pump lower connection (pipework not reversed).
- Check 4-way valve operation and coil.
Who to ask for: refrigeration / heat pump.
Certification: F-gas certification (refrigerant circuit work); R290 units require flammable-refrigerant competence.
What you might notice
Sources
- CTC EcoZenith i255 Installation and Maintenance Manual (400V 3N~/230V 1N~/230V 3~) ↗ · 162 505 67-9 CR01164 2026-05-10 · page 81 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026