Freeze Protection Operation - Rinnai RUC80i Training Program

Freeze Protection Operation

The freeze protection system on the RU/RUC and C199
model water heaters consists of electrically powered
ceramic heater elements installed on several pipes and
fittings inside the water heater cabinet.
➢ Heater activation is triggered by the outside air
temperature thermistor (thermistor #1) and/or the
intake air temperature thermistor (thermistor #2).
❖ Thermistor #1 (indoor and outdoor models) measures
the air temperature outside of the water heater
cabinet.
❖ Thermistor #2 (indoor models only) measures the air
temperature coming into the cabinet through the vent
system.
➢ Heaters are turned on when thermistor #1 or #2
detects air temperatures below 39⁰˚F.
❖ The main circuit board will cycle the heaters On and Off
on a specific cycle based on the air temperature.
NOTE:
Adequate incoming power is required for the
freeze protection system to operate correctly!
© 2016 Rinnai America Corporation
PROPRIETARY and CONFIDENTIAL
Enhancing Lives By Changing The Way Water Is Heated
Ceramic Heater examples
16
Thermistor #2
Thermistor #1
5/4/2018