Heat pumps · Error codes · Kronoterm
LpHeatKronoterm · TERMOTRONIC-controlled heat pumps (legacy WP / WPL / WPLV water-water, brine-water, air-water)
LpHeat on a Kronoterm TERMOTRONIC-controlled heat pumps: Alarm: refrigerant pressure too low during heating (displayed "LpHea")
Short answer
On a Kronoterm heat pump, LpHeat means: Alarm: refrigerant pressure too low during heating (displayed "LpHea"). 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: Alarm: refrigerant pressure too low during heating (displayed "LpHea").
Part involved: low pressure switch.
Likely causes:
- Insufficient air flow through evaporator.
- Frozen evaporator blades and basin.
- Insufficient source water/brine flow.
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.
Manual reset: After fixing the cause restart by holding ENTER for 3 s.
What you can check
- Note the exact message shown on the TERMOTRONIC display.
- Check the outdoor unit is not blocked by snow/ice/debris.
What the engineer will check
- Check fan, condensate drain, heating cable; manual defrost (max 2x); source pump/strainer/antifreeze for W/W and B/W.
Who to ask for: heat pump engineer / F-gas.
Certification: F-gas certification for refrigerant work.
What you might notice
Sources
- KRONOTERM Owner's manual for heat pumps water-water, brine-water and air-water (TERMOTRONIC controller), Id 17-16-19-2972-05 ↗ · 17-16-19-2972-05 · page 51, 58 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026