Rinnai ByPass Servo Troubleshooting Manual
[Type text]
Tankless
Water Heater
Troubleshooting Manual
WARNING
There are a number of live tests that are required when fault finding this product. Extreme care should be used
at all times to avoid contact with energized components inside the product.
You MUST be a qualified service person before proceeding with these test instructions.
Before checking resistance readings, turn off power source to unit and then isolate each item to be checked
from the circuit by unplugging it.
When setting gas pressures on one of these units, please check the complete model number you are troubleshooting. Gas pressures and dip switches can vary among models. Always check the rating plate for complete
information and follow directions.
If any of the original wire as supplied with the appliance must
be replaced, it must be replaced with type 18 AWG wire or its
equivalent.
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.
CAUTION
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Table of Contents
Code Numbers Page #
03 ……………………………………………………………………………………………………………………………………………… 4
05 ……………………………………………………………………………………………………………………………………………… 5
10 ……………………………………………………………………………………………………………………………………………… 6
11 ……………………………………………………………………………………………………………………………………………… 8
12 ……………………………………………………………………………………………………………………………………………… 11
14 ……………………………………………………………………………………………………………………………………………… 15
16 ……………………………………………………………………………………………………………………………………………… 17
19 ……………………………………………………………………………………………………………………………………………… 18
25 ……………………………………………………………………………………………………………………………………………… 19
31 ……………………………………………………………………………………………………………………………………………… 20
32 ……………………………………………………………………………………………………………………………………………… 21
33 ……………………………………………………………………………………………………………………………………………… 22
34 ……………………………………………………………………………………………………………………………………………… 23
41 ……………………………………………………………………………………………………………………………………………… 24
51 ……………………………………………………………………………………………………………………………………………… 25
52 ……………………………………………………………………………………………………………………………………………… 26
57 ……………………………………………………………………………………………………………………………………………… 27
58 ……………………………………………………………………………………………………………………………………………… 28
61 ……………………………………………………………………………………………………………………………………………… 29
63 ……………………………………………………………………………………………………………………………………………… 30
65 ……………………………………………………………………………………………………………………………………………… 31
70 ……………………………………………………………………………………………………………………………………………… 32
71 ……………………………………………………………………………………………………………………………………………… 33
72 ……………………………………………………………………………………………………………………………………………… 34
73 ……………………………………………………………………………………………………………………………………………… 35
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79 ……………………………………………………………………………………………………………………………………………… 36
No Code ……………………………………………………………………………………………………………………………………. 37
LC, LCO – LC9 .…………………………………………………………………………………………………………………………… 38
FF ………..……………………………………………………………………………………………………………………………………. 39
Cold Water Sandwich caused by Faulty Fixture…….. …………………………………………………………………. 40
Cold Water Sandwich caused by Low Flow .………………………………………………………………………………. 41
How to retrieve flow rate/temperature output with the MC-91-1 & MC-91-2 Controller….…….… 43
Rinnai America Corporation • 103 International Drive, Peachtree City, GA 30269
Toll-Free:1-800621-9419 • Phone: 678-829-1700 • www.rinnai.us
© 2013 Rinnai America Corporation. Rinnai is continually updating and improving products; therefore,
specifications are subject to change without prior notice. Local, state, provincial and federal codes must be
adhered to prior to and upon installation.
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Code 03 Troubleshooting Procedure
Power interruption during bath fill (Water will not flow when power returns)
1. Turn of all hot water fixtures in building. Next press the ON/OFF button on the temperature
controller twice.
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Code 05 Troubleshooting Procedure
Bypass Servo
1. Turn off power supply to unit, reapply power. Fire up unit. If code 05 reappears replace bypass
valve.
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Code 10 Troubleshooting Procedure
Air Supply or Exhaust Blockage
Inspect the entire vent system inside/outside the installation location. Check for clearance issues,
improper venting or materials used, etc.
1. Perform this test only if the unit is coding out during your service call. Remove the vent system from
the top of the water heater. Fire the product and see if the unit will operate without the vent system
connected. If the unit operates without coding out at that point that's a great indication the problem is
in the vent system leaving the unit. Ensure the front cover is installed on product before performing this
test. WARNING: Never leave a unit operating without the vent system connected. The test mentioned
above is only that, a test. If the unit functioned with the vent disconnected there is a 95% chance the
issue is in the vent pipe installation. Next go to step 2 below. There is a 5% chance it could be caused by
one of the items listed below.
2. Verify each vent section for proper installation. This will require disassembling each section to ensure
proper installation depth. Mark each vent pipe section with a marker before disassembling. This will
allow you to determine the proper depth when you disassemble the components. Make sure to use the
silicone grease Rinnai supplies with the condensing vent (PP) venting when reinstalling each vent
component. WARNING: Failure to use the grease will result in improperly sealed joints which will lead to
code 10 or exhaust gas leakage.
3. Inspect the vent system to ensure all clearances around vent terminations were met. Improper
clearances will result in recirculation of combustion gases.
4. Verify dip switch for vent length was set to the proper position for your application. First determine
total vent length, each ninety degree elbow counts as six foot of vent length, and each forty five degree
bend counts as three foot. Example; a vent system with two ninety degree elbows, one forty five degree
elbow and ten foot of straight pipe would be calculated as twenty five foot of total vent length.
5. If installer sprayed a foam sealant around the vent pipe penetration through the wall, check to ensure
this material did not collapse the intake pipe. Look down vent pipe with a flash light. If you can't see that
section of venting material remove it from the wall and inspect it.
6. Check for debris in vent system. Disconnect joints looking for water, condensation, insects or other
items.
7. Verify all vent terminations meet Rinnai's recommendation from another vent termination on the
same wall or roof. If multiple Rinnai's are installed at the location, each termination should have a
minimum of twelve inches of separation when installed on the same plane. If the vents are not on the
same plane you will need a five foot separation between vent terminations. See vent instructions for
details.
8. Verify vent terminals are installed with the proper clearance from overhangs, grade, obstructions,
walls, porches, etc. See venting instructions for proper clearance requirements.
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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
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Code 11 Troubleshooting Procedure
No Ignition
WARNING: You must be qualified to service gas systems before proceeding.
1. Verify all gas valves on gas system are open feeding the proper gas pressure to said appliance.
2. Verify all air was purged from gas lines after installation.
3. Verify proper inlet gas pressures are being fed to appliance. Check appliances rating plate for proper
pressures. This plate or label is located on the side of each unit. The minimum listed inlet pressure MUST
be maintained with all gas appliances at the location firing on high fire. If the product is a condensing
unit the front panel must be installed before testing inlet pressures.
4. Verify proper gas type; ensure the gas supply at this location matches that listed on said appliance.
5. Verify gas type dip switch on PC board is switch to proper gas type position.
6. Verify igniter is working. WARNING: Turn off gas valve feeding the appliance before preforming this
test. Unplug igniter wire; hold the igniter wire with an insulated pair of pliers about a 1/4" from a piece
of metal. Cycle the unit to ensure you see a spark when unit is cycling. If not, check ignition system for
loose connections, damaged components or disconnected plugs back to PC board. . If no spark is noted
check the ignition board to verify it is getting the proper voltage from the PC board. See troubleshooting
document under the unit's front cover for proper voltage and connector numbers. Note; there will be no
voltage present unless the unit is going through the ignition cycle.
7. Make sure the ceramic sparker electrode is tight in its mounting bracket. You should not be able to
move it with your finger if gasket is intact. If loose remove it and clean with dollar bill. Reinstall using
new gasket and ensure it is tight when the installation is finished. If the electrode is loose the tip can
drop down and touch the burners creating a short or no spark. A loose flame rod is called a floating
flame rod and will result in code 11’s or 12's.
8. Verify the proper flame rod wire is plugged into the proper flame rod. Some units have multiple flame
rods. A quick check to verify correct wiring is to look at the stamped letter on the bracket at flame rod,
sample a Y indicates yellow, R = red and B = blue
9. Verify the flame rod is tight in its mounting bracket. You should not be able to move it with your
finger if gasket is intact. If loose remove it and clean flame rod and igniter. Inspect flame rod for cracks
before re-installing it. Re-install using new gasket and ensure it is tight when installation is finished. A
loose flame rod is called a floating flame rod and will result in code 11's.
10. Look into view window on appliance to see if you ever see a flame in the burner box while the unit is
going through the ignition cycle. If you do that indicates an issue in the flame rectification circuit. This
could be a buildup of carbon or a white substance on flame rod, bad connection at flame rod, loose or
damaged flame rod, bad PC board, gas valve or low inlet gas pressures. Before replacing the PC board or
gas valve continue troubleshooting the steps below.
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11. WARNING: Turn off the electrical, gas and water supply before performing this inspection. Remove
the igniter and flame rod assemblies and inspect them for carbon or a white substance build-up. Clean
both components before re-installing them. If you removed just the igniter and flame rod assemblies,
make sure you have a new flame rod/igniter gasket before removing these components. This gasket
MUST be replaced if the seal is broken.
12. 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.
13. If you note improper inlet gas pressures check to see if the gas system was properly sized. If sized
properly you should see no more than a 0.3 inch pressure drop on natural gas with all gas appliances in
the building firing on high fire. The allowable pressure drop for propane is 0.5 inches of water column.
This pressure drop is based on the International Plumbing Code when operating on gas pressures up to
14" inches W.C. with black iron piping. There are a number of approved gas piping system out there,
make sure you refer to the manufacture's or International Plumbing Code book for pressure drops on
gas piping and pressures you are using for proper pressure drops allowed. If pressure drop excesses that
mentioned above for black iron gas systems, your system could be undersized, please recheck sizing.
The issue could be in any of the following items; the gas system, gas piping, regulator, tank, utility
supply, dirt or debris in gas system components, etc. Have the gas system checked by a professional gas
technical or master plumber that deals with gas system sizing. Refer to the International Plumbing Code
Book for proper gas system sizing for gas type, piping and pressures being used at this location.
14. Inspect vent system for loose joints, improper fittings, failure to meet clearances around vent
terminal outside building. See venting instructions for clearance specifications. Failure to meet vent
terminal clearances can lead to recirculation of combustion gases causing incomplete combustion which
will lead to carbon build up on flame rod. In addition; ensure vent length is within specifications and dip
switch for vent lengths has been properly set.
15. Verify that proper venting materials were used in this installation. They must use the correct venting
material for class III appliances approved by Rinnai. See Rinnai venting instructions for details.
16. Verify proper altitude settings, see high altitude gas pressure setting procedure for dip switch and
manifold gas pressure settings.
17. On internal units inspect the plastic tube running from the bottom of the combustion chamber to
the gas valve. If you find moisture in that tube, replace the gas valve. Also inspect the vent system to see
where the condensate/moisture is coming from. The burner and heat exchanger fins should be
inspected for excessive corrosion also. Signs of moisture could be a result of an improper venting or a
leak inside the heat exchange.
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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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Code 12 Troubleshooting Procedure
Flame Failure
NOTE; before troubleshooting your code 12 first determine what type code 12 is present. Look into the
view window while the appliance is going through the ignition cycle to see if you ever see a visible flame.
The reason for this is; there are two types of code 12's. The most common code 12 is called a flame
failure, meaning the appliance did sense a flame at one point. In other words you could see a visible
flame in the burner box during the ignition cycle and/or during operation. The other is called an
immediate code 12 and/or no flame was ever noted in the burner box. If you note a flame even for a
few seconds follow steps below. If no flame was ever noted proceed to the last item listed in these
instructions called, "Immediate code 12 or no flame visible in burner box".
Often it is difficult to distinguish between a gas code 12 or and electrical code 12. The easiest way to do
this is to turn off the gas and then try firing the unit. It should go to a code 11 at that point. If it goes
onto code 12 you have an electrical short in a component or wiring harness.
WARNING: You must be qualified to service gas systems before proceeding with the following items
listed below.
1. Verify proper inlet gas pressures are being fed to appliance. Check appliance rating plate for proper
pressures. This plate or label is located on the side of each unit. The minimum listed inlet pressure MUST
be maintained with all gas appliances at the location firing on high fire.
2. If you note improper inlet gas pressures check to see if the gas system was properly sized. If sized
properly you should see no more than a 0.3 inch pressure drop on natural gas with all gas appliances in
the building firing on high fire. The allowable pressure drop for propane is 0.5 inches of water column.
This pressure drop is based on the International Plumbing Code when operating on gas pressures up to
14" inches W.C. with black iron piping. There are a number of approved gas piping system out there,
make sure you refer to the manufacture's or International Plumbing Code book for pressure drops on
gas piping and pressures you are using for proper pressure drops allowed. If pressure drop excesses that
mentioned above for black iron gas systems, your system could be undersized, please recheck sizing.
The issue could be in any of the following items; the gas system, gas piping, regulator, tank, utility
supply, dirt or debris in gas system components, etc. Have the gas system checked by a professional gas
technical or master plumber that deals with gas system sizing. Refer to the International Plumbing Code
Book for proper gas system sizing for gas type, piping and pressures being used at this location.
3. Verify manifold gas pressures. You will need the gas pressure setting procedure for the model number
appliance you are working on. This information is normally found in a plastic holder on the back side of
the front panel. If procedure is not available contact Rinnai tech services for data. Verify correct dip
switch settings before adjusting/checking gas pressures. Dip switch settings can be found in the gas
pressure setting procedure. If in altitudes above two thousand foot in elevation refer to high altitude
settings and pressures. Next; connect your manometer to the gas valve test port. Fire the unit up
ensuring you have at least three gpm's of flow through the water heater. You can use the unit's key pad
to check your flow rate to verify three plus gpm's. Then; place the unit into forced low fire and follow
the gas pressure setting procedure to adjust the low fire gas pressure. Next place the unit into forced
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high fire per gas pressure setting procedure. Adjust high fire pressure per instructions. Improper
manifold gas pressures can lead to code 12's.
CAUTION: Verify all vent connections are properly seated per manufacturer’s venting instructions.
4. Inspect vent system for loose joints, improper fittings, failure to meet proper clearances around vent
terminal outside building. See venting instructions for clearance specifications. Failure to meet vent
terminal clearances can lead to recirculation of combustion gases causing incomplete combustion which
will lead to code 12. In addition; ensure vent length is within specifications and dip switch for vent
lengths has been properly set.
5. Ensure the proper venting materials were used in this installation. You must use concentric venting
material for class III appliances approved by Rinnai. See Rinnai venting instructions for details. Verify
venting component at unit's vent connection is fully engaged into top of water heater. Separate
connection to check for proper connection. You can mark the white vent material at the stainless steel
connection before pulling it apart to check depth once separated. Failure to have this joint fully engaged
will results in code 12's within ten seconds of the unit firing.
6. Make sure the flame rod is tight in its mounting bracket. You should not be able to move it with your
finger if the gasket is intact. If you remove the flame rod it is very important to note the orientation
before removal. After removing it, clean it before re-installing. Re-install the flame rod in the same
orientation as it was before removal. You MUST replace the flame rod/igniter gasket before reassembly.
Note; a loose flame rod is called a floating flame rod and will result in code 12's. Flame rods should
never have to be replaced unless the white ceramic is cracked or broken or the flame rod is damaged.
8. Inspect flame rod wires looking for loose or damaged wires or connectors at the flame rod and PC
board.
9. Inspect flame rod silicone protective sleeve for cracks or heat damage. If cracked or has heat damage
the spark could possibly seek a grounding source other than the intended target though the igniter,
replace the sleeve.
10. A properly grounded circuit is critical. Check to ensure all ground connections are intact, free of
corrosion, tight at each joint or connection and the polarity of the circuit is correct. If unsure contact a
Licensed Electrician to inspect and/or correct any issue with the circuit.
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.
11. Pull the unit's burner and inspect for debris and/or condensate around the burner located at flame
rod position. Clean all burners using 120 psi of compressed air. Blow out combustion chamber and
copper fins in heat changer while inside the burner box. If you are unable to clean out the debris
between the copper fins in the heat exchanger, replace heat exchanger. Note the copper surface where
the burner box and heat exchanger meet. If that surface appears black from heat stress that’s a good
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indication the fins inside the heat exchanger are clogged with debris. If you have heat damage on the
surface of the heat exchanger, replace the heat exchanger.
12. On internal units inspect the plastic tube running from the bottom of the combustion chamber to
the gas valve. If you find moisture in that tube replace gas valve. Also inspect the vent system to see
where the condensate is coming from. It could be a venting issue or leak inside the heat exchange
combustion box area.
13. Ensure 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. If stopped up remove vent pipe
from unit and clean out all debris or build up in the trap or drain lines.
14. Inspect fan blower wheel for debris and/or insects. Important; turn off power to unit before
unplugging fan motor or plugging it back up. Failure to do so can short out fan motor. If insects or debris
are found in the fan housing or burner assembly, inspect the entire intake air chamber to include the
vent system and air box chamber.
15. Check to ensure all 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 check 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.
16. 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. This can
cause a short circuit which will lead to code 12.
17. If any MSA or MSB system is in use isolate the unit from that system and see if it operates without
going to a code 12. A short circuit within those systems can cause a code 12.
18. See below for other suggestions:
a. 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.
b. 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.
c. 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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