Rinnai ByPass Servo Troubleshooting Manual page 7

9. CAUTION: Turn off power supply to unit. Remove fan motor and inspect fan wheel, housing, and air
duct for any type restriction. Re-install fan, after installation reapply power to unit and test for proper
operation.
10. WARNING: Turn off the electrical, gas and water supply to the water heater on the following series
product to perform this task, VA, VB, VC and KA units. Next; remove the burner manifold and inspect the
orifices on the back side of this manifold for clogged or blocked orifices. Proceed with removing the
burner assembly and inspect the chamber for insects or other debris. Clean out all debris found in the
burner and air chambers. Also inspect the copper fins in heat exchanger for a build-up between the fins.
Build-up or blockage between the heat exchanger fins will cause air flow restrictions, which will lead to
code 10's. If build up is present, you will need an air compressor capable of delivering 120 psi of
compressed air to blow out the burner and heat exchanger fins. If unable to clean the heat exchanger
with compressed air, replace the heat exchanger. CAUTION: Always wear safety glasses and a mask
when blowing out the burner.
WARNING: You must be qualified to service gas systems before proceeding with the following items
listed below.
12. Verify low and high fire manifold gas pressures are set correctly. Some model units have a burner
sensor if the manifold pressures are not properly set the temperature range for this senor may be too
low causing a code 10. This information can be found under the front cover in the plastic holder. If
missing contact Rinnai for proper gas pressure setting procedures.
13. Verify the manifold gas pressures and dip switches were properly set for your altitude. This
information can be found under the front cover in the plastic holder. If missing, contact Rinnai for
proper gas pressure setting procedures.
WARNING: Disconnect the electrical supply to the appliance before replacing items listed below.
14. Other items that could cause code 10's;
a. Bad fan motor bearing
b. Bad wiring harness to fan motor from PC board
c. Bad PC board
d. Improper dip switch settings
7
11112014GW