H62 on a Dimplex LA MI inverter outdoor air-to-water: Water flow fault: insufficient water flow between heat pump and house detected by the flow switch
Short answer
On a Dimplex heat pump, H62 means: Water flow fault: insufficient water flow between heat pump and house detected by the flow switch. 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: Water flow fault: insufficient water flow between heat pump and house detected by the flow switch.
Part involved: Flow switch.
When it shows: Flow below minimum: approx. 16.6 l/min LA6MI, 26.6 LA9MI, 35 LA12MI, 46.6 LA16MI.
Likely causes:
- Low flow rate.
- Blocked inline strainer on return.
- Air in pipework.
- Low system pressure.
- Pump speed not at max (III).
- 2-port valves slow/sticking at changeover.
- Non-standard hydraulics / bypass not set.
- Faulty flow switch or main water PCB (last).
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: unknown.
Manual reset: Clear via control panel per Dimplex article (method shown as image).
What you can check
- Check the heating system pressure gauge reads about 1.0-1.5 bar; if low, contact the installer.
- Note the code and contact the installer or Dimplex service.
What the engineer will check
- Isolate the heat pump from mains before any work.
- Measure flow with Taconova flow checker in HEAT and TANK modes.
- Clean return strainer.
- Purge air / power flush.
- Set pump to speed III.
- Test 2-port valves.
- Check sprung bypass.
- Test flow switch continuity.
Who to ask for: heat pump service engineer / heating engineer.
Certification: Electrical competence (Part P / qualified electrician) for work inside control panels.
What you might notice
Sources
- GDHV Help Centre article: i have h62 error on my la mi heat pump what does this mean ↗ · GDHV article (modified 2023-02) · page n/a (web article) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026