Rinnai COMBI i060C, Installation And Operation Manual, Page: 101 / 136

Rinnai I-Series Condensing Boiler Combi Manual 101
Heat Exchanger Overheat

Overheat switch is tripped.

Measure the resistance of the Overheat
Switch.*

Check the heat exchanger surface for hot
spots which may indicate blockage due
to scale buildup.

Ensure the boiler pump is not locked up.

Ensure that all of the valves in the CH
circuit are open.

Ensure the boiler and CH circuit does not
have a freezing condition.

The surface of the heat exchanger may
turn to a black color as stainless steel is
tempered even in normal conditions.
This does not indicate an abnormal
condition.

Check for damage on the exhaust, seal,
and venting.
Venturi Control

Venturi operation error.

Ensure the venturi motor is operating
correctly.*

Replace the gas valve assembly.
High Outgoing Temperature

Safety shutdown because DHW outgoing
temperature is too hot.

Check sensor wiring for damage of
outgoing thermistor.

Measure resistance of outgoing
thermistor.*

Ensure the gas valve has no damage and
the orifice is installed correctly.

Replace the gas valve assembly.
Venturi Blockage

Check the venturi and silencer for
blockage.

Before resetting this error, check if the
condensate drain is block and if the
venting is connected properly.
Electrical Grounding

Secondary circuit ground fault.

Check all electrical components for
electrical short.
Condensate Pump (Accessory)

Boiler will operate for 60 seconds.

Confirm wire connections and
harnesses are good.

Ensure the condensate reservoir is
empty and condensate pump is
operational.
Inlet Thermistor

Check sensor wiring for damage.

Measure the resistance of the sensor.

Replace if necessary.
Supply Thermistor

Check sensor wiring for damage.

Clean the surface of the sensor.

Measure the resistance of the sensor.

Check the return thermistor.

Replace if necessary.
Outgoing Thermistor

Check sensor wiring for damage.

Clean sensor of any scale buildup
present.

Measure the resistance of the sensor.

Replace if necessary.
Heat Exchanger Thermistor

Check sensor wiring for damage.

Measure the resistance of the sensor.

Replace if necessary.
Freeze Protection Thermistor

Check sensor wiring for damage.

Measure the resistance of the sensor.

Replace if necessary.
Exhaust Thermistor

Check sensor wiring for damage.

Clean the surface of the sensor.

Measure the resistance of the sensor.

Check the return thermistor.

Replace if necessary.
Return Thermistor

Check sensor wiring for damage.

Measure the resistance of the sensor.

Replace if necessary.
Outdoor Thermistor

Ensure that DIP switch 1 is set to the
appropriate position.

Check sensor wiring for damage.

Measure the resistance of the sensor.

Replace if necessary.
Pressure Sensor

Check sensor wiring for damage.

Measure the voltage of the sensor.

Replace if necessary.
* See “Electrical Diagnostics” on Technical Data Sheet located on inside front cover of boiler.