CH10 on a LG heat pump: BLDC water (circulation) pump lock – restriction or wrong connection of the BLDC water pump
Short answer
On a LG heat pump, CH10 means: BLDC water (circulation) pump lock – restriction or wrong connection of the BLDC water pump. 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: BLDC water (circulation) pump lock – restriction or wrong connection of the BLDC water pump.
Part involved: internal BLDC circulation pump.
When it shows: Pump speed feedback lost/low (R290 TS guide checks pump RPM below 50).
Likely causes:
- BLDC water pump defect; pump assembly condition abnormal; locked by foreign material; wrong connection or damaged driver cable; water circuit problems (leakage/low pressure) (R290 TS guide).
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: Service-engineer repair and restart required (LG: resumed only after certificated professional's check).
What you can check
- Read the code on the controller (LG shows 'CH' + number; older wired controllers alternate 'CH' and the number) and note it together with the model number. Report it to your installer or an LG-authorised service centre – LG owner's manuals say an error code generated by self-diagnosis is a reason to call the service. This is an 'Error'-class fault: LG says the system can only be resumed after a qualified professional has checked it, so do not keep trying to restart it. Look at the system pressure gauge and tell the engineer what it reads (LG commissioning guidance is roughly 1.5–2.5 bar when cold); do not top up or bleed the system yourself unless your installer has shown you how, and make sure any filling loop is closed.
What the engineer will check
- Check pump harness/connector and driver cable, pump RPM, system pressure (1.5-2.0 bar R290), leaks at expansion vessel/PHEX, strainer cleanliness, air in circuit; replace pump or PCB.
Who to ask for: Heating/heat pump engineer (wet-side hydraulics).
Certification: None statutory for sealed-system wet-side work; G3 unvented qualification if the DHW cylinder is worked on.
What you might notice
Sources
- LG THERMA V R290 Monobloc Trouble Shooting Guide (FHNW16606C0 / HM..HF UB60/UB40) – ManualsLib 4570773 ↗ · © 2023-2024 (revision not printed on viewed pages) · page 64, 71 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026