CodeRegistry
Brands
  1. Home
  2. Fujitsu
  3. Waterstage SuperHP Heat Pumps
  4. 122
About·Privacy·Terms

CodeRegistry — Your global library for technical solutions.

For your safety: always follow the equipment manufacturer’s official manuals. CodeRegistry is an independent help site and is not affiliated with the brands listed here.

122

Error 122 - HC2 flow temperature too low

Fujitsu · Waterstage SuperHP Heat Pumps

What does 122 mean?

The user interface displays '122: HC2 flow temperature too low', indicating that the flow temperature for Heating Circuit 2 is below the set threshold. This suggests insufficient heat delivery. This error typically triggers an automatic reset.

Common Causes

  • Insufficient heat generation by the heat pump for HC2.
  • Poor water circulation in HC2 due to closed valves or blockages.
  • Air trapped in the heating circuit.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the main power supply to the heat pump for 30 seconds, then turn it back on.

  2. 2

    Check the water pressure in Heating Circuit 2 and ensure all relevant valves are fully open.

  3. 3

    Allow time for the automatic reset to occur (default 6 hours) or use the manual reset function (Line 6711) if available.

  4. 4

    Contact a qualified service technician to diagnose the low flow temperature issue.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

10Error 10 - Outdoor sensor fault100Error 100 - Two master clocks on bus102Error 102 - Clock without running supply
Source: Fujitsu Waterstage SuperHP Heat Pumps
Open Manual (Page 93)Search more codes in this manual