Rinnai Boiler: Central heating works, no domestic hot water
Central heating works, no domestic hot water on a Rinnai boiler: Heating runs but no DHW.
Applies to: E50CRN; E75CRN; E75CRP; E110CRN; E110CRP
Common causes of central heating works, no domestic hot water
- DHW program key not on
- Flow switch not working
- T3 DHW sensor in plate heat exchanger defective
- RS100 timer or DHW program not responding
- Three-way valve not moving to DHW
How to fix central heating works, no domestic hot water: step by step
- Switch the DHW program on at the Control Tower.
- Check the flow switch for impurities and operation; replace if needed.
- Replace the T3 DHW sensor if defective.
- If using an RS100, check its DHW timer times and see its instructions.
- Check three-way valve wiring; replace the valve motor if needed.
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.