American Water Heater 30 Gallon UltraLow NOx Natural Gas Water Heater GU6130T30 User Manual

							21
Operating the Temperature 
Control SystemFigure 19B: Status Codes
VAC
List of status codes are shown
at top of gas control valve/thermostat.
Water Temperature Adjustment
The water temperature setting can be adjusted from 55°F 
to 155°F. Turn the Gas Control/Temperature Knob to the 
desired setting/temperature.
NOTE: The temperatures indicated are approximates. The 
actual temperature of the heated water may vary.  Also, 
some models are certified for 180°F outlet temperatures. 
See the Data Plate on the front of the water heater for the 
maximum outlet temperature.
Operating Modes and Settings
The gas control valve has two different operating modes: 
Standard and Vacation.  
Standard mode allows you to adjust the water temperature 
to your desired setting.  
Vacation (VAC) mode sets the thermostat at approximately 
55°F and is recommended when not using hot water for 
an extended period of time.  The VAC setting also reduces 
energy losses and keeps the tank from freezing during cold 
weather, but it can cause a Hydrogen gas build up in the 
water system.  See caution on page 2.  
NOTE: The actual temperature of the water in most 
installations will be greater than 55°F due to the 
surrounding environment and the pilot flame.
Status Light Codes
Normal Flashes: 
•  0 Flashes   Indicates Control Off/Pilot Out.
•  1 Flash  Indicates Normal Operation.
•  Continuous Light indicates the gas control  valve/thermostat is shutting down.
Diagnostic Flashes: If the water heater is not working, look 
for the following diagnostic flashes after lighting the pilot.
2 Flashes   Indicates thermopile voltage is low.
4 Flashes  Indicates overheat failure.         
5 Flashes   Indicates water temperature sensor failure.
7 Flashes   Indicates electronic control failure.
8 Flashes   See “Status Light Code Troubleshooting Chart.”
9 Flashes   Indicates chamber temperature sensor circuit         is open or shorted.
10 Flashes  Indicates an LDO occurrence was detected in      the combustion chamber (contaminants).
Operational Conditions
Condensation
Moisture from the products of combustion condenses on 
the tank surface and the outside jacket of the water heater 
and forms drops of water which may fall onto the burner or 
other hot surfaces. This will produce a “sizzling” or “frying” 
noise. NOTE: This condensation is normal and should 
not be confused with a leaking tank. Condensation may 
increase or decrease at different times of the year.
High efficient energy saver water heaters will produce 
larger amounts of condensation on initial start-up or when 
a large amount of hot water is being used.  NOTE: Do not 
confuse this with a “tank leak”. Once the water reaches a 
temperature of 120°F and the tank warms up (usually 1-2 
hours), the condensation will stop.
IMPORTANT: It is always recommended that a suitable 
metal drain pan be installed under the water heater 
to protect the area from water damage resulting from 
normal condensation production, a leaking tank or piping 
connections. Refer to “Location Requirements” on page 
4. Under no circumstances is the manufacturer to be held 
responsible for any water damage in connection with this 
water heater.
Water Heater Sounds
During the normal operation of the water heater, sounds or 
noises may be heard. These noises are common and may 
result from the following:
1.  Normal expansion and contraction of metal parts during  periods of heat-up and cool-down.
2.  Condensation causes sizzling and popping within the  burner area and should be considered normal.
3.  Sediment buildup in the tank bottom will create varying  amounts of noise and may cause premature tank fail-
ure. Drain and flush the tank as directed under “Drain-
ing and Flushing”. 
						

							22associated with the anode rod is a “rotten egg smell” 
produced from the presence of hydrogen sulfide gas 
dissolved in the water. 
IMPORTANT: Do not remove this rod permanently as it will 
void any warranties. A special anode rod may be available 
if water odor or discoloration occurs.
NOTE: This rod may reduce but not eliminate water odor 
problems. The water supply system may require special 
filtration equipment from a water conditioning company to 
successfully eliminate all water odor problems.
Artificially softened water is exceedingly corrosive because 
the process substitutes sodium ions for magnesium and 
calcium ions. The use of a water softener may decrease 
the life of the water heater tank.
The anode rod should be inspected after a maximum of 
three years and annually thereafter until the condition of 
the anode rod dictates its replacement. 
NOTE: artificially softened water requires the anode rod to 
be inspected annually.
The following are typical (but not all) signs of a depleted 
anode rod:
•  The majority of the rods diameter is less than 3/8”.
•  Significant sections of the support wire (approx. 1/3 or 
more of the anode rod’s length) are visible.
If the anode rod show signs of either or both it should be 
replaced. NOTE: Whether re-installing or replacing the 
anode rod, check for any leaks and 
immediately correct if found.
In replacing the anode:
1.  Turn off gas supply to the water 
heater.
2.  Shut off the water supply and 
open a nearby hot water faucet to 
depressurize the water tank.
3.  Drain approximately 5 gallons 
of water from tank. (Refer to 
“Draining and Flushing” for proper 
procedures). Close drain valve.
4.  Remove old anode rod.
5.  Use Teflon® tape or approved pipe 
sealant on threads and install new anode rod.
6.  Turn on water supply and open a nearby hot water 
faucet to purge air from water system.
7.  Check for any leaks and immediately correct any if 
found.
8.  Restart the water heater as directed in this manual. 
See the Repair Parts Illustration for anode rod location.
TEFLON ® is a registered trademark of E.I. Du Pont De Nemours and Company.
Smoke/Odor
The water heater may give off a small amount of smoke 
and odor during the initial start-up of the unit. This is due to 
the burning off of oil from metal parts of a new unit and will 
disappear after a few minutes of operation. 
Safety Shut-off
This water heater is designed to automatically shut-off in 
the event of the following:
1.  The pilot flame is extinguished for any reason.
2.  The water temperature exceeds 189°F (87°C).
3.  Excessive contaminants in the combustion chamber.
4.  The ignition of flammable vapors.
A thermopile is used to determine if a pilot flame is present 
and will shut off the gas supply to the main burner and pilot 
if the flame is absent.  This unit is also equipped with a 
combustion chamber temperature sensor that will shut off 
the gas supply to the burner if poor combustion is sensed 
(caused by a blocked vent or insufficient combustion air).  If 
the gas control valve/thermostat shuts off the gas supply, 
check the diagnostic flash code and refer to the “Status 
Light Code Troubleshooting Chart.”  If necessary, also refer 
to the “Troubleshooting Chart.”
IMPORTANT: Correct any issues prior to resetting the gas 
control valve/thermostat.  Reference the telephone number 
on the cover of this manual for service information. 
  
Reset the system by following these steps:  1.) Turn the 
temperature adjustment knob to OFF.  2.) Unplug the 
thermopile plug from the gas control valve/thermostat.  
3.) Wait for about three minutes.  4.) Plug the thermopile 
plug back into the gas control valve/thermostat.  5.) Turn 
the temperature adjustment knob to PILOT and restart the 
water heater as directed in this manual.
  
A temperature limit switch or ECO (Energy Cut Off)  sensor  
located in the gas control valve	hermostat is used to shut 
off the water heater if the water temperature exceeds 
189°F (87°C).
The Diagnostic Status Light will flash a code indicating 
an “Overheat Failure” (4 Flashes).  See “Operating the 
Temperature Control System.”  If the ECO has functioned 
the gas control valve/thermostat should be replaced by 
a qualified person. Contact your local dealer for service 
information.
Anode Rod/Water Odor
Each water heater contains at least one anode rod, 
which will slowly deplete (due to electrolysis) prolonging 
the life of the water heater by protecting the glass-lined 
tank from corrosion. Adverse water quality, hotter water 
temperatures, high hot water usage, hydronic heating 
devices, and water softening methods can increase 
the rate of anode rod depletion. Once the anode rod 
is depleted, the tank will start to corrode, eventually 
developing a leak.
Certain water conditions will cause a reaction between the 
anode rod and the water. The most common complaint  
						

							23
MAINTENANCE OF YOUR WATER HEATER
Draining and Flushing
It is recommended that the tank be drained and flushed 
every 6 months to remove sediment which may build up 
during operation. The water heater should be drained if 
being shut down during freezing temperatures. To drain the 
tank, perform the following steps:
1.  Turn off the gas to the water heater at the manual gas 
shut-off valve.
2.  Open a nearby hot water faucet until the water is no 
longer hot.
3.  Close the cold water inlet valve.
4.  Connect a hose to the drain valve and terminate it to an 
adequate drain or external to the building.
5.  Open the water heater drain valve and allow all of the 
water to drain from the tank. Flush the tank with water 
as needed to remove sediment.
6.  Close the drain valve, refill the tank, and restart the 
heater as directed in this manual.
If the water heater is going to be shut down for an extended 
period, the drain valve should be left open.
IMPORTANT: Condensation may occur when refilling the 
tank and should not be confused with a tank leak.
Routine Preventative 
Maintenance
At least annually, a visual inspection should be made of 
the venting and air supply system, piping systems, main 
burner, pilot burner, and Flame-trap. Check the water 
heater for the following:
•  Obstructions, damage, or deterioration in the venting 
system. Make sure the ventilation and combustion air 
supplies are not obstructed. 
•  Build up of soot and carbon on the main burner and 
pilot burner. Check for a soft blue flame.
•  Leaking or damaged water and gas piping.
•  Presence of flammable or corrosive materials in the 
installation area.
•  Presence of combustible materials near the water 
heater.
•  After servicing this water heater, check to make sure it 
is working properly. (See Operating Your Water Heater 
section of this manual.)
IMPORTANT: If you lack the necessary skills required to 
properly perform this visual inspection, you should not 
proceed, but get help from a qualified person.
Temperature and Pressure 
Relief Valve
Manually operate 
the temperature 
and pressure relief 
valve at least once 
a year to make 
sure it is working 
properly. To prevent 
water damage, 
the valve must be 
properly connected 
to a discharge line 
which terminates 
at an adequate 
drain. Standing clear of the outlet (discharged water may 
be hot), slowly lift and release the lever handle on the 
temperature and pressure relief valve to allow the valve to 
operate freely and return to its closed position. If the valve 
fails to completely reset and continues to release water, 
immediately shut off the manual gas control valve and the 
cold water inlet valve and call a qualified person.
WARNING! When manually operating the temperature-
pressure relief valve, make sure that no one is in front of or 
around the discharge outlet.  The water may be extremely 
hot and could cause severe burns.   Also ensure that the 
water discharge will not cause property damage.
Figure 21
Temperature and Pressure
Relief Valve
Manual Relief
Valve
Discharge line to drain
Explosion Hazard
If the temperature and pressure relief valve 
is dripping or leaking, have a qualified 
person replace it.
Examples of a qualified person include:
licensed plumbers, authorized gas company 
personnel, and authorized service 
personnel.
Do not plug valve.
Do not remove valve.
Failure to follow these instructions can 
result in death, or explosion.
WARNING 
						

							24
Replacement Parts
IMPORTANT: The following maintenance procedures are 
for the Flame Guard™ Safety System components and 
should be performed by a qualified person.
Replacement parts may be ordered through your plumber 
or the local distributor. Parts will be shipped at prevailing 
prices and billed accordingly. When ordering replacement 
parts, always have the following information ready:
1.  model, serial, and product number
2.  type of gas
3. item number
4. parts description
See pages 32-33 for a list of available repair parts.
Removing the Burner Door Assembly
1.  Turn off the gas to the water heater at the manual 
shut-off valve (Figure 3).
2.  Before performing any maintenance, it is important to 
turn off the gas supply to the 
water heater at the manual 
gas shut-off valve. This valve 
is typically located beside 
the water heater. Note the 
position of the shut-off valve 
in the open/on position, then 
proceed to turn it off (Figure 
3).
3.  Remove the outer door.
4.  Remove the two screws 
(1/4” nut driver) securing 
the burner door assembly 
to the combustion chamber 
(Figure 23).
5.  Disconnect the pilot tube 
(7/16” wrench), the igniter wire from the igniter lead 
wire, and manifold tube  (3/4” wrench) at the gas 
control valve/thermostat.  Disconnect the sensor wires 
(lift white lever outward, then gently pull the plug 
downward). Also, use needle nose pliers to disconnect 
the red (+) and white (-) thermopile wires from the gas 
control valve/thermostat. See Figures 22 & 23.   
Figure 23
Burner Assembly
Removal
Burner Door Screws (2)
Manifold Component BlockBurner DoorTemperature
SensorManifold Tube
Pilot Tube
ViewportThermopile 
Wire
Connections
Piezo Igniter ButtonGas Control Valve/
ThermostatTemperature Sensor
Wire Connection
Outer Door
Not Shown
VAC
Igniter
WireRed
Wire
(Left 
 Side) Pilot 
Tube
Manifold 
Tube Igniter
Button Figure 22
Gas Control Valve/
Thermostat
Igniter
Lead
Wire
White
Wire
(Right
 Side)
VACSensor 
Wires
6.  Grasp the manifold tube and push down slightly to free 
the manifold, pilot tube, and thermopile.
7.  Carefully remove the burner door assembly from the 
burner compartment.  
 NOTE: Be sure not to damage internal parts.
Figure24A
NaturalGas(Low Nox)
Burner Door Assembly
Burner
Use brush on this surface.Pilot Assembly
Figure24B
NaturalGas(Low Nox)
Burner Door Assembly
50K Models
Burner
Use brush on this surface.Pilot Assembly
Natural Gas Burner (Ultra Low Nox)
Check the burner to see if it is dirty or clogged. The burner 
may be cleaned with soft paint brush (Figure 24). Do not 
use a wire brush or any tool that may damage the burner 
screen. Important: Do not use the burner if the burner screen 
is damaged. NOTE: Damage may be rips or holes in the 
burner screen. Discoloration is normal. 
						

							25
Replacing the Pilot/Thermopile Assembly
1.  Remove the burner assembly. See Removing the Burner Door Assembly  Section.
2.  Lift the retainer clip straight up from the back of the manifold component block (using a flat-blade 
screwdriver), then remove the manifold component 
block from the burner door (Figure 25). IMPORTANT: 
Be careful not to bend or alter the position of the pilot 
tube. Note the placement/order of the wires in the 
manifold component block.
Figure 25 
Manifold Component
Block Assembly
Thermopile
Connectors
Manifold 
Component
Block
Pilot Tube
Igniter
Wire
Burner Door Opening
Retainer
Clip
3.  Turn the burner door assembly over until the pilot/ thermopile assembly is easily accessible.
4.  Use a 7/16” wrench to loosen the nut securing the pilot  tube to the pilot (right-hand threads). IMPORTANT: 
Be careful not to bend or alter the position of the pilot/
thermopile assembly components during the following 
steps. To prevent any bending, use a pair of pliers to 
steady the pilot/thermopile assembly bracket.
  
5.  Locate and remove the screw attaching the pilot/thermopile assembly to the burner and keep it for reuse 
later. 
IMPORTANT: Be careful not to bend or alter the 
position of the pilot/thermopile assembly components.
Figure 26
Pilot/Thermopile Assembly
Pilot/Thermopile
Assembly
Igniter Connector
Pilot
Thermopile
Thermopile
Connectors
Pilot Tube
(Ferrule Nut 
Not Shown)
6.  Install the new pilot/thermopile assembly by routing the  new igniter wire and new thermopile wire through the 
opening in the burner door (See Figure 25). 7.  Use the screw removed earlier to attach the new pilot/
thermopile assembly to the burner door assembly. 
NOTE: Remove the pilot nut included with the new 
pilot/thermopile. IMPORTANT: Once the pilot nut is 
removed the pilot orifice MUST be kept in the pilot.
8.  Connect the pilot tube to the new pilot and tighten the  nut securely. To prevent any bending, use a pair of pli-
ers to steady the pilot bracket. IMPORTANT: Keep the 
pilot orifice in the pilot when making the connection. 
DO NOT operate the water heater without the pilot ori-
fice installed.
9.  Reinstall the manifold component block in the burner  door. (See Figures 25). Be sure that the thermopile 
wires are positioned through the top opening of the 
manifold component block. The igniter wire should be 
positioned through the middle opening and the pilot 
tube through the bottom opening.
10.  Follow the “Replacing the Burner Door Assembly”  instructions to replace the burner door assembly.
Replacing the Pilot/Thermopile 
Assembly (50K Models)
1.  Remove the burner assembly as directed previously.
2.  Lift the retainer clip straight up from the back of the manifold component block (using a flat-blade 
screwdriver), then remove the manifold component 
block from the burner door assembly
 (Figure 27).
Figure 27 
Manifold Component
Block Assembly (50K Models)
Thermopile
Connectors
Manifold 
Component
Block
Pilot Tube
Igniter
Wire
Burner Door Opening
Retainer
Clip
3.  Locate and remove the screw attaching the pilot/ thermopile assembly to the burner and keep it for reuse 
later. 
IMPORTANT: Be careful not to bend or alter the 
position of the pilot/thermopile assembly components.    
4.  Pull the pilot/thermopile assembly from the burner door  assembly. IMPORTANT: Be careful not to bend or alter 
the position of the pilot assembly components.
5.  Use the old pilot tube as a guide and bend the new pilot tube to match the old one. Make only the bends 
closest to the pilot before going to the next step. 
						

							26
Pilot Thermopile Pilot/Thermopile
AssemblyPilot Tube
(Ferrule Nut 
Not Shown) Igniter 
Connector
Thermopile
Connectors Figure 28
Pilot/Thermopile Assembly
(50K Models)
6.  Push the new pilot/thermopile assembly connectors 
through the opening in the burner door (See Figure 27). 
Do not to scrape or nick the wires during installation. 
IMPORTANT: DO NOT USE PILOT/THERMOPILES 
WITH FIBERGLASS SLEEVES. The replacement kit 
does not contain a fiberglass sleeve over the pilot/
thermopile wires.
7.  Attach the pilot assembly to the Burner Door Assembly.
8.  Position the new thermopile wires through the top 
opening of the manifold component block (Figure 27). 
Be sure that the igniter wire is positioned through the 
middle opening of the manifold component block.  
Position the pilot tube through the bottom opening of 
the manifold component block.
9.  See “Replacing the Burner Door Assembly” section. 
NOTE: Use the ferrule nut supplied with the new pilot/
thermopile assembly when connecting the pilot tube to 
the gas control valve/thermostat.
External Inspection & Cleaning of the 
Flame-trap
Although not likely to occur, if debris collects on the flame-
trap, use a vacuum, compressed air, or a soft bristle brush 
to remove it.  
NOTE: If unable to inspect or clean the flame trap from 
underneath, follow the “Cleaning the Combustion Chamber 
and Flame-trap” section instructions.
Figure 29
Flame-trap visual inspection 
Mirror Flashlight
Cleaning the Combustion Chamber and 
Flame-trap
1.  Follow procedure outlined in “Removing the Burner 
Door Assembly”.
2.  Use a vacuum cleaner/shop vac to remove all loose 
debris in the combustion chamber (Figure 30). Use 
compressed air to clear any dust or debris that may 
have accumulated in the flame-trap.
3.  Reassemble following the procedure under “Replacing 
the Burner Door Assembly”.
Replacing the Burner Door Assembly
result in death, explosion, or fire.
 
 
WARNING
Replace manifold component block if missing
or removed.
Replace door gasket if damaged.
Failure to follow these instructions can Replace viewport if glass is missing or
damaged.Tighten both burner door screws
securely.Explosion Hazard
Remove any fiberglass between gasket
and combustion chamber.
1.  Check the door gasket for damage or imbedded debris 
prior to installation.
2.  Inspect the viewport for damage and replace as required.
3.  Insert the burner assembly into the burner 
compartment, making sure that the burner assembly 
sits firmly against the burner bracket inside the 
combustion chamber (Figure 30). 
IMPORTANT: 
Do not to scrape or nick the wires during 
installation.
 
4.  Inspect the door gasket and make sure there is no 
fiberglass insulation between the gasket and the 
combustion chamber.
5.  Replace the two screws which secure the burner 
assembly to the combustion chamber and tighten 
securely. There should be no space between the 
gasket part of the burner door and combustion 
chamber. IMPORTANT: Do not operate the water heater  
						

							27 if the door gasket does not create a seal between the 
burner door and the combustion chamber.
6.  Reconnect the manifold tubing (3/4” wrench), pilot 
tubing (7/16” wrench), temperature sensor wires, and 
thermopile wires to the gas control valve/thermostat. 
(See Figure 22 for the correct position of the thermopile 
wires.)  Do not cross-thread or apply any thread sealant 
to the fittings. NOTE: If installing a new pilot tube 
install the provided ferrule nut in the gas control valve/
thermostat at the pilot location, hand tight only. Next, 
insert the pilot tube into the ferrule nut until it bottoms 
out. Hold the tube in this position. Tighten the ferrule 
nut with a 7/16” wrench until the crimp connection seals 
to the pilot tube. Continue to tighten until the nut is tight 
in the gas control valve/thermostat.     
7.  Reconnect the igniter wire.
8.  Turn the main gas supply on and check the gas supply 
connections for leaks. Use an approved noncorrosive 
leak detection solution. If such a solution is not available, 
use a mixture of hand dish washing soap and water (one 
part soap to 15 parts water) or childrens’ soap bubble 
solution. Bubbles forming indicate a leak. Correct any 
leak found. 
9.  Follow the “Lighting Instructions” on page 17.
10.  With the pilot and main burner lit, check the manifold 
tube and pilot tube connections for leaks. Correct 
any leak found. Use an approved noncorrosive leak 
detection solution. IMPORTANT: All leaks must be fixed 
immediately.
11.  Replace the outer door.
Figure 30
Combustion Chamber
Door GasketBracketFlame-trap
Piezoelectric Igniter System
The piezoelectric igniter system consists of the igniter 
button, electrode, and wire.  The pilot is ignited by an 
electric spark generated when the igniter button is pressed.  
(See Figure 31). Use only factory authorized piezoelectric 
igniter parts for replacement.
VAC
Pilot/Thermopile Bracket
(Opposite Side)Electrode Thermopile
Pilot
Igniter ButtonWire to Electrode Figure 31
Gas Igniter Assembly
Testing the Igniter System
Turn off the gas to the water heater at the manual gas shut-
off valve. Watch the electrode tip while activating the igniter. 
A visible spark should jump from the electrode. To avoid 
shock, do not touch the burner or any metal part on the 
pilot or pilot assembly. If no spark is visible, check the wire 
connections and make sure the electrode is not broken. 
Replace the igniter if defective. Dirt and rust on the pilot or 
electrode tip can prevent the igniter spark. Wipe clean with 
a damp cloth and dry completely. Rust can be removed 
from the electrode tip and metal surfaces by lightly sanding 
with an emery cloth or fine grit sandpaper. 
						

							28
Flame Guard™ Safety System Operational Checklist
TROUBLESHOOTING CHART
4.  Manifold component block properly installed.
5.  No leaks at pilot and manifold connection.
6.  Burner door screws securely tightened.  1.  Burner door gasket properly sealed.
2.  Viewport not damaged or cracked.
3.  Flame-trap free of debris and undamaged.
PROBLEM POSSIBLE CAUSE(S) CORRECTIVE ACTION
BURNER WILL NOT IGNITE 1.  Pilot not lit
2.  Thermostat set too low
3. No gas
4.  Dirt in the gas lines
5.  Pilot line clogged
6.  Main burner line clogged
7. Non-functioning thermopile
8. Non-functioning thermostat
9.  Heater installed in a confined area1. Light pilot
2.  Turn temp. dial to desired temperature
3.  Check with gas utility company
4.  Notify utility-install trap in gas line
5.  Clean, locate source and correct
6.  Clean, locate source and correct
7. Replace thermopile
8. Replace thermostat
9.  Provide fresh air ventilation
SMELLY WATER 1.  Sulfides in the water 1.  Replace the anode with a special anode
BURNER FLAME YELLOW-
LAZY1.  Insufficient secondary air
2.  Low gas pressure
3. Flue clogged
4.  Main burner line clogged
5.  Heater installed in a confined area
6.  Obstruction in main burner orifice1.  Provide ventilation to water heater
2.  Check with gas utility company
3.  Clean, locate source and correct
4.  Clean, locate source and correct
5.  Proper fresh air ventilation
6.  Clean or replace orifice
PILOT WILL NOT LIGHT OR 
REMAIN LIT1. Non-functioning igniter
2.  Thermopile connection loose
3.  Air in gas line
4.  Proper Lighting Sequence not followed.  
Gas Control / Temperature Knob was not 
held in for sufficient time.
5.  Low gas pressure
6. No gas
7.  Dirt in gas lines
8. Cold drafts1.  Replace igniter pilot assembly
2.  Seat connector firmly in socket
3.  Bleed the air from the gas line
4.  Do not attempt to relight if the status light is 
lit and the pilot flame is not visible through 
the view port.  Wait until the status light is no 
longer lit, then follow lighting instructions on 
the water heater.
5.  Check with gas utility company
6.  Check with gas utility company
7.  Notify utility-install sediment trap in gas line
8.  Locate source and correct
Removing and Replacing the Gas 
Control Valve/Thermostat
Removing the Gas Control Valve/Thermostat:
1.  Turn the gas control/temperature knob  to the “OFF” 
position (Figure 19A).
2.  Turn off the gas at the manual shut-off valve on the gas 
supply pipe (Figure 3).
3.  Drain the water heater. Refer to the section on “Draining 
and Flushing” and follow the procedure.
4.  Disconnect the igniter wire from the igniter lead wire. 
Disconnect the temperature sensor wire, then use 
needle nose pliers to disconnect the red (+) and white 
(-)  thermopile wires.  Disconnect  the pilot tube (7/16” 
wrench) and manifold tube (3/4” wrench) at the gas 
control valve/thermostat  (Figure 22). Refer to “Gas 
Piping” (Figure 3) and disconnect the ground joint union 
in the gas piping. Disconnect the remaining pipe from 
the gas control valve/thermostat.
5.  To remove the gas control valve/thermostat, thread a 4”  
section of gas pipe into the inlet and use it to turn the 
gas control valve/thermostat (counterclockwise.) Do not 
use a pipe wrench or equivalent to grip body.  Damage 
may result.  Do not insert any sharp objects into the 
inlet or outlet connections. Damage to the gas control 
valve/thermostat may result.Gas Control Valve/Thermostat:
To replace the gas control valve/thermostat, reassemble 
in reverse order. When replacing the gas control valve/
thermostat, thread a 4” section of gas pipe into the inlet and 
use it to turn the gas control valve/thermostat (clockwise.) 
DO NOT OVER TIGHTEN, damage may result. 
•  Be sure to use approved Teflon® tape or pipe joint 
compound on the gas piping connections and fitting on 
the back of the gas control valve that screws into the 
tank.
•  Be sure to remove the pilot ferrule nut from the new gas 
control valve/thermostat.
•  Turn the main gas supply on and check the gas supply 
connections for leaks. Use an approved noncorrosive 
leak detection solution. If such a solution is not available, 
use a mixture of hand dish washing soap and water (one 
part soap to 15 parts water) or childrens’ soap bubble 
solution. Bubbles forming indicate a leak. Correct any 
leak found. 
•  Be sure tank is completely filled with water before 
lighting and activating the water heater. Follow the 
“Lighting Instructions” on page 17.
•  With the pilot and main burner lit, check the manifold 
tube and pilot tube connections for leaks. Correct any 
leak found. 
•  If additional information is required, reference the 
number on the cover of this manual for service 
information.
TEFLON® is a registered trademark of E.I. Du Pont De Nemours and Company. 
						

							29
PROBLEM POSSIBLE CAUSE(S) CORRECTIVE ACTION
PILOT WILL NOT LIGHT OR 
REMAIN LIT (continued)9.  ECO switch open
10.  Pilot line or orifice clogged
11. Non-functioning thermopile
12.  Air for combustion obstructed
13.  Flammable vapors incident, Flame Guard™ 
function utilized9.  Replace gas control valve/thermostat
10.  Clean, locate source and correct
11. Replace thermopile
12.  See maintenance section for inspection and   
cleaning of flame trap 
13.  Replace water heater, eliminate flammable 
vapors source. Reference the number on the 
cover of this manual for service information.
HIGH OPERATION COSTS 1.  Thermostat set too high
2.  Sediment or lime in tank
3.  Water heater too small for job
4.  Wrong piping connections
5. Leaking faucets
6. Gas leaks
7.  Wasted hot water
8.  Long runs of exposed piping
9.  Hot water piping in exposed wall1.  Set temperature dial to lower setting
2.  Drain/flush-provide water treatment if needed
3.  Install adequate heater
4.  Correct piping-dip tube must be in cold inlet
5. Repair faucets
6.  Check with utility-repair at once
7. Advise customer
8. Insulate piping
9. Insulate piping
INSUFFICIENT HOT WATER 1.  Thermostat set too low
2.  Sediment or lime in tank
3.  Water heater too small
4.  Wrong piping connections
5. Leaking faucets
6.  Wasted hot water
7.  Long runs of exposed piping
8.  Hot water piping in outside wall
9.  Low gas pressure1.  Turn temperature dial to desired setting
2.  Drain/flush-provide water treatment if needed
3.  Install adequate heater
4.  Correct piping-dip tube must be in cold inlet
5 Repair faucets
6. Advise customer
7. Insulate piping
8. Insulate piping
9.  Check with gas utility company
SLOW HOT WATER 
RECOVERY1.  Insufficient secondary air
2. Flue clogged
3.  Low gas pressure
4. Improper calibration
5.  Thermostat set too low
6.  Water heater too small
7.  Wrong piping connections
8.  Wasted hot water1.  Provide ventilation to water heater. Check flue 
way, flue baffle, and burner
2.  Clean flue, locate source and correct
3.  Check with gas utility company
4. Replace thermostat
5.  Turn temperature dial to desired setting
6.  Install adequate heater
7.  Correct piping-dip tube must be in cold inlet
8. Advise customer
DRIP FROM RELIEF VALVE 1.  Excessive water pressure
2. Heater stacking
3.  Closed water system1.  Use a pressure reducing valve and relief valve
2.  Lower the thermostat setting
3.  See “Closed System/Thermal Expansion”
THERMOSTAT FAILS TO 
SHUT-OFF1.  Thermostat not functioning properly
2. Improper calibration1. Replace thermostat
2. Replace thermostat
COMBUSTION ODORS 1.  Insufficient secondary air
2. Flue clogged
3.  Heater installed in a confined area1.  Provide ventilation to water heater. Check flue
  way, flue baffle, and burner
2.  Clean, locate source and correct
3.  Provide fresh air ventilation
SMOKING AND  CARBON 
FORMATION (SOOTING)1.  Insufficient secondary air
2.  Low gas pressure
3. Flue clogged
4.  Thermostat not functioning properly
5.  Heater installed in a confined area
6.  Burner flame yellow-lazy1.  Provide ventilation to water heater. Check flue 
way, flue baffle, burner
2.  Check with gas utility company
3.  Clean, locate source and correct
4. Replace thermostat
5.  Provide fresh air ventilation
6.  See “Burner Flame Yellow-Lazy”
CONDENSATION 1.  Temperature setting too low 1.  Increase the temperature setting
BURNER FLAME FLOATS 
AND LIFTS  OFF PORTS1.  Orifice too large
2.  High gas pressure
3. Flue clogged
4. Cold drafts1.  Replace with correct orifice
2.  Check with gas utility company
3.  Clean flue and burner-locate source and correct
4.  Locate source and correct
BURNER FLAME TOO HIGH 1.  Orifice too large 1.  Replace with correct orifice
PILOT FLAME
TOO SMALL1.  Pilot line or orifice clogged
2.  Low gas pressure1.  Clean, locate source and correct
2.  Check with gas utility company 
						

							30
STATUS LIGHT CODE TROUBLESHOOTING CHART 
LED STATUS PROBLEM CORRECTIVE ACTION
0 FLASHES (LED NOT LIT) Pilot light is not lit. Not enough 
power (millivolts) to keep it lit.Follow the lighting instructions on the front of the 
water heater and record any diagnostic codes. 
See Status Light Codes section.
1 FLASH (EVERY 3 SECONDS) Normal operation. No corrective action necessary.
2 FLASHES Insufficient power (millivolts) to the 
gas control valve/thermostat.1.  Check all wiring connections. If problem 
persists proceed to step 2.
2.  Replace the thermopile. See “Replacing the 
Pilot/Thermopile Assembly.”
4 FLASHES High water temperature has 
activated the over heat sensor.Replace the gas control valve/thermostat. See 
“Removing and Replacing the Gas Control Valve/
Thermostat.”
5 FLASHES Water temperature sensor failure Replace the gas control valve/thermostat. See 
“Removing and Replacing the Gas Control Valve/
Thermostat.”
7 FLASHES Gas Control Valve/Thermostat 
failure.Replace the gas control valve/thermostat.  See 
“Removing and Replacing the Gas Control Valve/
Thermostat.”
8 FLASHES This condition only appears if the 
gas control/temperature knob has 
been turned off and the thermopile 
continued to produce electric 
power. This condition can occur if 
the thermopile does not cool down 
as quickly as expected when the 
unit is shut off. This condition 
can also occur if the gas control/
temperature knob has been 
turned off and the pilot continues 
to operate because the pilot valve 
is stuck in the open position.Make sure that the gas control valve/thermostat 
knob is set to OFF. Wait one minute. Remove 
the outer door. Look through the sight glass for 
a pilot flame. If a pilot flame is observed with the 
gas control valve/thermostat knob set to the OFF 
position, the pilot valve is stuck open. Turn the 
main gas supply OFF. Replace the gas control 
valve/thermostat. For instructions, see “Removing 
and Replacing the Gas Control Valve/Thermostat.”
If the pilot flame is not observed when the gas 
control valve/thermostat knob is set to the OFF 
position, wait 10 minutes for the thermopile to cool, 
then attempt to relight the pilot by following the 
lighting instructions on the water heater’s label. 
If this condition returns, replace the gas control 
valve/thermostat. See “Removing and Replacing 
the Gas Control Valve/Thermostat” for instructions.
9 FLASHES Combustion chamber temperature 
sensor circuit is open or shorted1.  Check all connections. If the problem persists, 
proceed to step 2.
2.  Replace the temperature sensor.  
(Temperature sensor replacement must be 
performed by a qualified person.)  If the 
problem persists, proceed to step 3.
3.  Replace the gas control valve/thermostat.  For 
instructions, see “Removing and Replacing 
the Gas Control Valve/Thermostat.”
10 FLASHES LDO occurrence was detected 
in the combustion chamber 
(contaminants)1.  Reset the system by following these steps:  1.) 
Turn the temperature adjustment knob to OFF.  
2.) Unplug the thermopile plug from the gas 
control valve/thermostat.  3.) Wait for about 
three minutes.  4.) Plug the thermopile plug 
back into the gas control valve/ thermostat.  
5.) Turn the temperature adjustment knob to 
PILOT and restart the water heater as directed 
in this manual.  If the problem persists, proceed 
to step 2.
2.  Follow the procedure outlined in “Cleaning the 
Combustion Chamber and Flame-Trap.”  
If the problem persists, proceed to step 3. 
3.  Shut off the gas supply to the water heater 
and contact Technical Assistance.  The 
telephone number is listed on the cover of this 
manual.