46 on a Viessmann Vitotronic 200: Short circuit/lead break, liquid gas temperature sensor

What it means

The manual says: Short circuit/lead break, liquid gas temperature sensor.

Part involved: Short circuit/lead break, liquid gas temperature sensor.

When it shows: Type "Fault" (S) - triggers "05 Refrigerant circuit" on the heat pump control unit. Heat pump characteristics: Compressor OFF.

Likely causes:

• Short circuit/lead break, liquid gas temperature sensor.

Is it safe?

The heat pump stops until the fault clears or is reset.

Resetting itself: Not stated in 6150133.

Manual reset: Refrigerant circuit messages cannot be acknowledged in the message history (6150133 p.155); acknowledge the resulting 05/07/A9 message on the control unit.

What you can check

• This code is only visible to engineers in the service menu (Diagnosis > Refrigerant circuit > Message history); homeowners see message 05, 07 or A9 - note that code and call your contractor.

What the engineer will check

• Vitocal 200-A/222-A:.
• Check resistance value (NTC 10 k) Ω at connection J21 (T3) of the EEV PCB: See "EEV PCB [4-3] / [4-4] ". Vitocal 200-S/222-S:.
• Check resistance value (Pt500A) at connection F25 (X25.17/X25.18) of the controller and sensor PCB: See "Controller and sensor PCB".

Who to ask for: Viessmann-trained heat pump engineer with F-gas refrigeration certification.

Certification: F-gas certificate (UK F-gas Regulations; Viessmann: refrigerant work by authorised refrigeration engineers only).

What you might notice

• No heating
• No hot water
• Keeps stopping / cutting out

Sources

• Service instructions Vitotronic 200 type WO1C heat pump control unit (air/water split & monobloc, brine/water) (6150133, 2023-07) ↗ · 6150133 VSA00004 · page 168 · Reviewed 23 September 2026

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

Reviewed: 23 September 2026