7H on a Daikin Altherma LT: Flow abnormality
Short answer
On a Daikin heat pump, 7H means: Flow abnormality. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Flow abnormality.
Part involved: water flow / circulation pump / flow sensor.
When it shows: The error is generated in case the water flow is too low or no water flow at all (minimum required water flow is 16 l/min).
Likely causes:
- Closed shut off valve; Air in the system; Clogged water filter; Insufficient water pressure; Too high external static pressure (pump speed setting); Malfunction of pump; Pump fuse open [FU2]; Malfunction of pump relay [K4M]; During defrost; Malfunction of the backup heater [Q1L, F1T]; Backup heater fuse [F1B]; In case of EKHWS(U) / EKHWE; Malfunction of the 3-way valve; In case of the EKHWSU; Malfunction of the tank thermostat [Q1T, Q3L]; Malfunction of 2-way valve ESIE10-02 Error Codes: Hydro-box Part 3 –.
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: Reset via the remote controller (Inspection/Test button) after the cause is fixed; some codes need a manual reset of the remote-controller memory (service manual section 1.4).
What you can check
- Read the full error code shown on the user interface and note it, with the date/time, for your installer.
- Check the heating-system water pressure reading on the gauge/display: Daikin operation manuals ask users to check it is above 1 bar. If it is below that, report it to your installer (do not open the unit).
What the engineer will check
- Follow the service-manual troubleshooting flow chart for this code: check closed shut off valve; check air in the system; check clogged water filter; check insufficient water pressure; check too high external static pressure (pump speed setting); check malfunction of pump.
Who to ask for: Heat pump installer / heating engineer.
Certification: None specific for water-side checks; MCS-certified installer recommended.
What you might notice
What owners and engineers report
1 owner and engineer report mentions this.
- No heating on the Altherma LT (low temperature split): 1 report
Sources
- Service Manual ALTHERMA ERHQ006~008BAV3 / ERLQ006~008BAV3(9) / EKHBH(X)008BA (ESIE10-02) ↗ · ESIE10-02 · page 152 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026