Rinnai Tankless Water Heater Installaon and Operaon Manual 59
4.5 Diagnosc Codes
Some of the checks below should be performed by a licensed professional. Consumers
should never aempt any acon that they are not qualied to perform.
WARNING
To display diagnosc codes:
1. Turn o the water heater by pressing the “On/O” buon.
2. Press and hold the “On/O” for 2 seconds and then the (Up)
buon simultaneously.
3. The last nine maintenance codes display and ash one aer the other.
4. To exit diagnosc codes and return the water heater to normal
operaon, press and hold the “On/O” buon for 2 seconds and
then the (Up) buon simultaneously.
5. Turn on the water heater by pressing the “On/O” buon.
1
2
03 Power interrupon during bath ll
(Water will not ow when power returns)
• Turn o all hot water taps. Press ON/OFF twice.
05 By-Pass Flow Control
• Measure resistance values of the by-pass ow control.*
• Replace By-Pass ow control device.
10
Air Supply or Exhaust Blockage/Condensate Trap
is Full
• Ensure condensate line is not blocked.
• Ensure internal air lter is clean with no obstrucons.
(Indoor Water Heaters Only)
• Ensure High Altude seng. (See Parameter Sengs)
• Ensure Combuson air and Exhaust vents are not blocked
and approved venng materials are being used. (Indoor
Water Heaters Only)
• Ensure vent length is within limits. (Indoor Water Heaters
Only)
• Check fan for debris and ensure wheel turns freely.
• Verify check valve is not stuck between fan casing and
burner body.
11 No Ignion (Heater Not Turning On)
• Check that the gas is turned on at the water heater,
meter, or cylinder.
• If the system is propane, make sure that gas is in the tank.
• Ensure gas type and inlet gas pressure are correct.
• Bleed all air from gas lines.
• Check the ground wire for the PC Board.
• Ensure ame rod wire is connected.
• Ensure igniter is operaonal.*
• Check gas solenoid valves for open or short circuits.*
• Verify gas orice is correct.
12
No Flame
• Check that the gas is turned on at the water heater, gas
meter, or cylinder.
• If the system is propane, make sure that gas is in the tank.
• Ensure ame rod wire is connected.
• Ensure gas type and inlet gas pressure is correct.
• Bleed all air from gas lines.
14
Heat Exchanger Overheat
• Measure resistance of Overheat Switch.*
• Check heat exchanger surface for hot spots which indicate
blockage due to scale build-up.
• Refer to instrucons in manual for ushing heat exchanger.
Hard water must be treated to prevent scale build up or
damage to the heat exchanger.
• Ensure it is not in forced Hi seng.
15
Venturi Control
• Ensure the Venturi motor is operang correctly.*
• Replace gas valve assembly.
• Clear diagnosc code by reseng the main power supply to
the water heater.
16
High Outgoing Temperature
(safety shutdown because water heater is too hot)
• Conrm fan motor is funconing correctly.
• Replace the gas valve assembly.
17
Venturi Blockage
• First, follow the recommended soluons for Diagnosc Code
10.
• If the Code 10 soluons do not correct the problem, ensure
the Venturi is not blocked.
• Please call Rinnai technical department.
19
Electrical Grounding
• Check all components for electrical short.
* See “Electrical Diagnoscs” on Technical Data Sheet located on inside front cover of water heater.