Rinnai ByPass Servo Troubleshooting Manual page 10

18. Verify the condensate drain trap was used as recommended by Rinnai on the vent terminal
connection at the top of the water heater, non-condensing product. If the condensate drain line is not
connected please install one per Rinnai venting instructions. If a condensate line is in use, inspect the
vent connector on top of water heater to ensure it's not stopped up. In addition; check the condensate
drain trap and line for blockage. If stopped up remove vent pipe from unit and clean out all debris
and/or build up from the trap or line.
WARNING: You must be qualified to service gas systems before proceeding with the following items
listed below.
19. Check the two stages regulators are installed at least six foot away from appliance. Ensure when
appliance shuts off the pressure from the two stage regulator doesn't exceed the maximum inlet
pressure for the appliance. To verify this connect your manometer up to the test port on the bottom of
the water heater. The inlet pressures should never exceed 10 inches water column for natural gas or
13.5 inches on propane. If it does the regulator may be defective.
20. WARNING: Disconnect power supply to unit to perform this inspection. Inspect all wiring harnesses
throughout unit for water or moisture in electrical connections. If any connections appear to be damp or
wet dry them out and try to find out what is causing this.
21. If using an MSA or MSB system isolate the unit giving trouble from the system during
troubleshooting. If unit operates when isolated the issue may be in the electronic staging system (MSA
or MSB).
22. Other suggestions; 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.
a. Verify spark electrode is installed in the correct position.
b. Verify all burner cassettes are in place in burner rack. Sometimes when contractors drop a unit
the burners can shift and become dislodged. If you find the burners dislodged loose burner
bracket and reseat them.
c. Remove the four burners located under the flame rod and move them over to the high fire side
of the burner tray. Move the four burners from the high fire side over under the flame rod.
Sometimes condensate or debris can get down in the burners and cause turbulence inside the
burner.
d. Condensate, debris or a malfunctioning mechanical component inside the gas valve may be
preventing the valve from opening correctly once in a while. Replace gas valve.
e. Voltage output to gas valve from PC board could be incorrect or intermittent due to a bad
component on PC board, replace PC board.
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