SolarpunkHomes
Sign inCall us · +44 7510 081687
Heat pumps
Heat pumps · Error codes · Toshiba
P19Toshiba

P19 on a Toshiba heat pump: 4-way valve inversion failure

Short answer

On a Toshiba heat pump, P19 means: 4-way valve inversion failure. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.

Reviewed 23 September 2026 · 4 sources

What it means

On the R32 Estia 1-Series (split, Wall-Mounted and All-in-One)

The manual says: 4-way valve inversion failure.

Part involved: refrigerant charge, PMV, valves, pressure switch/sensor.

When it shows: TE > 30C or TS > 50C during heat pump operation.

Likely causes:

  • 4-way valve or coil.
  • PMV defect.
  • TE/TS sensors.

On the Estia (Series 4) Standard & Powerful

The manual says: 4-way valve inversion error.

Part involved: refrigerant charge, PMV, valves, pressure switch/sensor.

When it shows: TE > 30C or TS > 50C during heat pump operation.

Likely causes:

  • 4-way valve/coil.
  • PMV defect.
  • TE/TS sensors.

On the Estia 5 Series (Standard)

The manual says: 4-way valve inversion error.

Part involved: refrigerant charge, PMV, valves, pressure switch/sensor.

When it shows: TE > 30C or TS > 50C during heat pump operation.

Likely causes:

  • 4-way valve/coil.
  • PMV defect.
  • TE/TS sensors.

On the Estia 5 Series Powerful (Hi Power / Extreme)

The manual says: 4-way valve inversion error.

Part involved: refrigerant charge, PMV, valves, pressure switch/sensor.

When it shows: Trigger thresholds not printed in the IM; see SM.

Likely causes:

  • 4-way valve/coil.
  • PMV defect.
  • TE/TS sensors.

Is it safe?

Does the heat pump stop?Partly
SeverityFault — needs a manual reset once the cause is fixed
Engineer needed?Yes

The heat pump keeps running with some functions stopped.

Resetting itself: no.

Manual reset: Cause must be fixed by an engineer; hardware faults reappear until repaired.

What you can check

  • Note the check code shown on the remote controller and the outdoor/hydro model numbers before contacting an engineer.
  • Check the outdoor unit is not blocked by leaves, debris, snow or ice, and that nothing is covering the air inlet/outlet.

What the engineer will check

On the R32 Estia 1-Series (split, Wall-Mounted and All-in-One)

  • Follow manufacturer's check-code flowchart.
  • 4-way valve or coil.
  • PMV defect.
  • TE/TS sensors.

Who to ask for: F-gas certified refrigeration / heat pump engineer.

Certification: F-gas Category I; R32 is A2L mildly flammable - trained handler required.

On the Estia (Series 4) Standard & Powerful

  • Follow manufacturer's check-code flowchart.
  • 4-way valve/coil.
  • PMV defect.
  • TE/TS sensors.

Who to ask for: F-gas certified refrigeration / heat pump engineer.

Certification: F-gas Category I; R32 is A2L mildly flammable - trained handler required.

On the Estia 5 Series (Standard)

  • Follow manufacturer's check-code flowchart.
  • 4-way valve/coil.
  • PMV defect.
  • TE/TS sensors.

Who to ask for: F-gas certified refrigeration / heat pump engineer.

Certification: F-gas Category I; R32 is A2L mildly flammable - trained handler required.

On the Estia 5 Series Powerful (Hi Power / Extreme)

  • Follow manufacturer's check-code flowchart.
  • 4-way valve/coil.
  • PMV defect.
  • TE/TS sensors.

Who to ask for: F-gas certified refrigeration / heat pump engineer.

Certification: F-gas Category I; R32 is A2L mildly flammable - trained handler required.

What you might notice

Sources

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 23 September 2026