PP2 on a Warmflow heat pump: Suction Pressure Sensor Error

What it means

The manual says: Suction Pressure Sensor Error.

Part involved: refrigerant pressure sensor/transducer.

Likely causes:

• The pressure sensor is faulty or disconnected.

Is it safe?

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

What you can check

• Note the exact code shown on the controller (a photo helps) and report it to your installer or the manufacturer's service line.
• Check the heat pump's supply breaker/isolator at the consumer unit is on (do not open any casing).

What the engineer will check

On the Zeno A-Series air source heat pump (R32) AS01-R32/AS02-R32/AS03-R32

• Test the operation of the suction line pressure sensor and re-connect/replace if necessary.

Who to ask for: refrigeration / controls.

Certification: F-gas certified engineer if the refrigerant circuit is opened.

On the Zeno A-Series air source heat pump (R410A) AS01/AS02/AS03

• Test the operation of the refrigerant suction line pressure sensor and re-connect/replace if necessary.

Who to ask for: refrigeration / controls.

Certification: F-gas certified engineer if the refrigerant circuit is opened.

What you might notice

• Heat pump will not start

Sources

• Warmflow High Efficiency Variable Speed Air Source Heat Pumps A-Series AS01-R32 / AS02-R32 / AS03-R32 - User, Installation & Service Instructions (9007723 Issue C) ↗ · 9007723 Issue C · page 55 · Reviewed 23 September 2026
• Warmflow High Efficiency Variable Speed Air Source Heat Pumps A-Series AS01 / AS02 / AS03 (R410A Zeno) - User, Installation & Service Instructions (Issue 7) ↗ · Issue 7 · page 48 · Reviewed 23 September 2026

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

Reviewed: 23 September 2026