Error Code 15 - Rheem RTG2-42 Troubleshooting Manual

Error Code 15

Explanation: Boiling Safety Device. The heat exchanger is too hot. At a minimum check the
following:
1. Check for restrictions in airflow around unit and vent terminal.
2. Check for a foreign materials in exhaust venting.
3. Back flush the unit to remote any sediment of buildup in the heat exchanger.
See section on how to display maintenance information.
Display maintenance information line [4y] Heat Exchanger Thermistor temperature.
If 4Y displays 199°F – then physically check heat exchanger (Remote cannot display over
199°F.)
If actual temperature reaches 207°F for 15 seconds, Error code 15 displays. Unit will re-start
at 194°F.
If actual temperature reaches 210°F for 1 second, unit shuts down. Unit will re-start at 194°F.
If actual temperature reaches 230°F, Error code 15 displays. Unit will not automatically
restart.
Does the
maintenance
information
indicate the heat
exchanger temp?
Yes
The water heater appears to be
normal. Attempt to operate again.
SVC 810 Tankless Troubleshooting Manual
Is the resistance
No
to the heat
exchanger
thermistor OK?
Yes
Replace Printer Circuit
Board.
52
No
Replace Heat Exchanger
Thermistor.
Measure the resistance of connector
R between Black#3 and Yellow#5
wires: 4k - 10 k ohms