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Rinnai · Boiler troubleshooting

Radiators not hot enough or slow to heat

What is going on

Heating performance is poor.

Likely causes

  • Room thermostat or RS100 setting
  • Supply temperature setpoint too low
  • Wrong installation type in parameter 2
  • System resistance too high (boiler cuts load when delta T exceeds 36 F)

Check in this order

  1. Check thermostat / RS100 settings.
  2. Check PARA parameter 1 and raise if needed.
  3. Check PARA parameter 2.
  4. Check and clean the water filter; verify pipe sizing.

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.