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Rinnai · Boiler troubleshooting

Hot water works, no central heating

What is going on

DHW is available but there is no space heating.

Likely causes

  • CH program key off
  • On/off room thermostat sending no call
  • RS100 with outdoor sensor: outdoor temperature above the Eco setting (default 70 F)
  • Three-way valve not going to CH position

Check in this order

  1. Switch central heating on.
  2. Check the room thermostat.
  3. With RS100, check INFO step 7 and the timer and room temperature settings.
  4. Check three-way valve wiring; replace the valve motor if needed.

Applies to: E50CRN; E75CRN; E75CRP; E110CRN; E110CRP

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Source: Rinnai E-Combi Series Installation & Servicing Instructions (8U516009 V0116), p.77 (15.4). Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.