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Heat pumps · Error codes · Worcester Bosch
E1X.TT.T5-shortWorcester Bosch · Greenstore LECP ground source heat pump (System & Combi)

E1X.TT.T5-short on a Worcester Bosch Greenstore LECP ground source heat pump: Short circuit on sensor E1X.TT.T5 room

Short answer

On a Worcester Bosch heat pump, E1X.TT.T5-short means: Short circuit on sensor E1X.TT.T5 room. The heat pump keeps running. An engineer is needed to fix the cause.

Reviewed 23 September 2026 · 1 source

What it means

The manual says: Short circuit on sensor E1X.TT.T5 room.

Part involved: T5 room sensor.

When it shows: Sensor above +70 C; room influence set to 0.

Likely causes:

  • Sensor above +70 C; room influence set to 0.

Is it safe?

Does the heat pump stop?No
SeverityFault — clears by itself when the condition goes
Engineer needed?Yes

The heat pump keeps running.

Resetting itself: yes.

Manual reset: Automatic.

What you can check

  • Read and note the full alarm text and category letter shown on the controller and pass it to your installer.

What the engineer will check

  • Diagnose per chapter 21: Sensor above +70 C; room influence set to 0.

Who to ask for: heat pump installer / controls engineer.

Certification: None specific; electrical isolation required before wiring checks.

What you might notice

Sources

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

Reviewed: 23 September 2026