Hitachi Yutaki M & Yutaki S fault 75

What it means

Freeze Protection triggered by cold water inlet or outlet temperature detection.

Likely causes

1. Low water inlet or outlet temperature risk of freezing
2. Built-in sensor reading differs from actual ambient room temperature due to sensor location or controller self-heating

Where to start

1. Check water inlet and outlet temperatures for freeze risk conditions
2. Confirm unit is capable of heating and cooling, and cooling operation is enabled, before this function is available
3. Check Status is enabled for Auto Heat/Cool