Rinnai Boiler: Insufficient hot water quantity
Insufficient hot water quantity on a Rinnai boiler: Low DHW flow.
Applies to: E50CRN; E75CRN; E75CRP; E110CRN; E110CRP
Common causes of insufficient hot water quantity
- Hot and cold connections swapped
- Wrong or dirty flow reducing valve
- Scale in the plate heat exchanger
How to fix insufficient hot water quantity: step by step
- Check connections (left hot, right cold).
- Check restrictor type and cleanliness; clean or replace.
- Descale or replace the plate heat exchanger if nothing else helps.
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.