Mitsubishi Electric · Heat pumps · Mitsubishi Electric Ecodan FTC7 controller (PUZ-WM/WZ, PUHZ-SW)
L5Indoor unit temperature thermistor (THW1, THW2, THW5A, THW5B, THW6, THW7, THW8, THW9) failure
Name in the manufacturer's documentation (service manual): Indoor unit temperature thermistor (THW1, THW2, THW5A, THW5B, THW6, THW7, THW8, THW9) failure
[1]
In plain words (editorial)
One of the indoor water temperature thermistors has failed. The manual says to check the resistance across the thermistor.
When to call a service technician: The measurement is done by the installer.
✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.
For technicians
Steps given by the manufacturer (source text)
- Check resistance across the thermistor[2]
⚠ Work on refrigerant circuits, mains electricity and PV DC wiring is for qualified technicians only.
The Polish page has more detail (plain-language explanation, safe checks, guides): Read in Polish →
Sources
Every statement has a footnote to the document and PDF page. “Quote verified” means the quote was found automatically in the text of that page.
- [1] Mitsubishi Electric Ecodan FTC7 PAC-IF081B-E / PAC-IF082B-E / PAC-IF083B-E – Installation Manual (DG79H200H02) , p. 33 official manufacturer document quote verified
L5 Indoor unit temperature thermistor
- [2] Mitsubishi Electric Ecodan FTC7 PAC-IF081B-E / PAC-IF082B-E / PAC-IF083B-E – Installation Manual (DG79H200H02) , p. 33 official manufacturer document quote verified
Check resistance across the thermistor.