E219 on a CTC control system alarm/information platform: Blocking alarm after the fourth [E211] Risk of freezing low flow - heat pump blocked, contact installer
Short answer
On a CTC heat pump, E219 means: Blocking alarm after the fourth [E211] Risk of freezing low flow - heat pump blocked, contact installer. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Blocking alarm after the fourth [E211] Risk of freezing low flow - heat pump blocked, contact installer.
Part involved: heating circuit flow.
Likely causes:
- Heating circuit temperature and/or flow rate too low.
- Faulty HP in/HP out sensors (E135/E216).
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Safety lockout |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Manual reset: Critical alarms [E135]/[E211]/[E216]/[E217] can be acknowledged three times with code 4005 (Installer/Service/Coded settings); after the fourth the heat pump is blocked; counters reset after one year without alarms.
What you can check
- Note the alarm code/text, the product model and serial number and contact your installer.
- Check radiator/UFH valves in the house are not all closed.
- Check system pressure gauge reading is in the normal range.
What the engineer will check
- Check circulation pump speed, dirt filter, pipe sizes and flow sensor.
- Ensure heating return at least 25 C during defrost; consider volume tank.
- Check HP in/out sensors with an external thermometer and replace if required.
Who to ask for: heat pump / hydraulic.
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 82 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026