Rinnai Boiler: DHW temperature drops
DHW temperature drops on a Rinnai boiler: Hot water temperature falls during use.
Applies to: E50CRN; E75CRN; E75CRP; E110CRN; E110CRP
Common causes of dhw temperature drops
- Hot and cold connections swapped
- Wrong flow reducing valve
- DHW power set too low
- T3 sensor or wiring fault
How to fix dhw temperature drops: step by step
- Check connections.
- Check restrictor type against the installation instructions.
- Check PARA parameter 43.
- Check DHW sensor T3 and wiring.
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.
If the unit shows an error code, look it up: Rinnai Boiler codes
Models
I-Series Plus 150K and smaller
I-Series Plus 175K and higher
Source: Rinnai E-Combi Series Installation & Servicing Instructions (8U516009 V0116), p.77 (15.4). Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.