American Water Heater 40 Gallon 38000 BTU Direct Vent Natural Gas Water Heater DVG6240S38NOV user manual

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Natural gas and Propane (LP) 
main burner with igniter assembly 
for 38k to 42k Btu/hr models
31
36
38
39
30
33
34
35
32
37
40
Flare 
Nut 
††
†
Figure 47 
37
Natural gas and Propane 
(LP) main burner with igniter 
assembly for 47k Btu/hr 
models
353634
33
32
31
4039
3830
Flare 
Nut 
†††
Figure 48 
Notes:
† The orifi ce on Natural gas models has Right-hand 
thread, the orifi ce on Propane (LP) models has Left-
hand thread.
††  For Natural gas models the Flare Nut has Right-hand 
thread. For Propane (LP) models the Flare Nut has 
Left-hand thread.   
						

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TROUBLESHOOTING GUIDELINES
PROBLEM POSSIBLE CAUSE(S) CORRECTION
BURNER WILL NOT 
IGNITE1.  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. Defective thermopile
8.  Defective gas control/thermostat1. 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 gas control/thermostat
SMELLY WATER1.  Sulfur in the water 1.  Replace the anode with a special 
anode
2.  Raising the water heater temperature 
setting to  140°F  may help to eliminate 
the odo r (will require the use of a 
mixing valve)
BURNER FLAME 
YELLOW-LAZY1.  Low gas pressure
2. Flue clogged
3.  Main burner line clogged
4.  Obstruction in main burner orifice
5.  Insufficient combustion air1.  Check with gas utility company
2.  Clean, locate source and correct
3.  Clean, locate source and correct
4.  Clean or replace orifice
5.  Check that the vent termination hood 
and venting pipe is not blocked
PILOT WILL NOT LIGHT 
OR REMAIN LIT1. Air in gas line
2. No gas
3. Dirt in gas lines
4.  Pilot line or orifice clogged
5. Defective thermopile
6.  Insufficient combustion air
7.  Gas control/thermostat ECO switch 
open
8.  Defective igniter or electrode
9.  Low gas pressure
10. Incorrect  gas1.  Bleed the air from the gas line
2.  Check with gas utility company
3.  Notify utility-install sediment trap (dirt 
leg) in gas line
4.  Clean, locate source and correct
5. Replace thermopile
6.  Check that the vent termination hood 
and venting pipe is not blocked
7.  Replace gas control/thermostat
8.  Replace igniter or pilot assembly
9.  Check with gas utility company
10. Check rating plate for correct gas type. 
Check with gas utility company
HIGH OPERATION 
COSTS1.  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 size 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
PILOT FLAME TOO 
SMALL1.  Pilot line or orifice clogged
2.  Low gas pressure
3. Defective pilot
4. Incorrect gas1.  Clean, locate source and correct
2.  Check with gas utility company
3. Replace pilot
4.  Check rating plate for correct gas type. 
Check with gas utility company 
						

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PROBLEM POSSIBLE CAUSE(S) CORRECTION
INSUFFICIENT HOT 
WATER1.  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 pressure
10. Leaks or cracks in dip tube
11. Incorrect  plumbing/plumbing  crossover1.  Turn temperature dial to desired setting
2.  Drain/flush-provide water treatment if 
needed
3. Install adequate size 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
10. Check dip tube. Replace if faulty
11. Correct  cold  water  crossover
SLOW HOT WATER 
RECOVERY1.  Insufficient combustion air
2. Venting/flue clogged
3.  Low gas pressure
4. Improper calibration
5.  Gas control/thermostat set too low
6.  Water heater too small
7.  Wrong piping connections
8.  Wasted hot water
9.  Sediment or lime in tank1.  Check vent termination hood and 
venting, flueway, flue baffle and burner
2.  Clean flue, locate source and correct
3.  Check with gas utility company
4.  Replace gas control/thermostat
5.  Turn temperature dial to desired 
setting
6. Install adequate size heater
7.  Correct piping-dip tube must be in 
cold inlet
8. Advise customer
9.  Drain/flush - provide water treatment if 
needed
DRIP FROM RELIEF 
VA LV E1.  Excessive water pressure
2. Heater stacking
3. Closed water system/thermal 
expansion1.  Use a pressure reducing valve and 
relief valve
2.  Lower the thermostat setting
3. See “Closed System/Thermal 
Expansion”
THERMOSTAT FAILS TO 
SHUT OFF1.  Defective gas control/thermostat
2. Improper calibration1.  Replace gas control/thermostat
2.  Replace gas control/thermostat
COMBUSTION ODO RS1.  Insufficient ventilation air
2.  Flue clogged or vent system blocked
3.  Heater installed in a confined area1.  Provide ventilation to the water heater. 
Check flueway, flue baffle, burner
2.  Clean, locate source and correct
3.  Provide fresh air ventilation
SMOKING AND  CARBON 
FORMATION (SOOTING)1.  Insufficient combustion air
2.  Low gas pressure
3. Venting/flue clogged
4.  Defective gas control/thermostat
5.  Burner flame yellow-lazy1.  Check vent termination hood and 
venting, flueway, flue baffle and burner
2.  Check with gas utility company
3.  Clean, locate source and correct
4.  Replace gas control/thermostat
5.  See “Burner Flame Yellow-Lazy”
CONDENSATION1.  Temperature setting too low
2.  Water heater too small1. Increase the temperature setting
2. Install adequate size heater
BURNER FLAME 
FLOATS AND  LIFTS  OFF 
PORTS1.  Orifice too large
2.  High gas pressure
3. Flue clogged1.  Replace with correct orifice
2.  Check with gas utility company
3.  Clean flue and burner-locate source 
and correct
BURNER FLAME TOO 
HIGH1.  Orifice too large
2.  High gas pressure1.  Replace with correct orifice
2.  Check with gas utility company
FLAME BURNS AT 
ORIFICE1.  Defective gas control/thermostat
2.  Low gas pressure
3.  Orifice not properly installed1.  Replace gas control/thermostat
2.  Check with gas utility company
3.  Reinstall the orifice 
						

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STATUS LIGHT AND DIAGNOSTIC CODE 
TROUBLESHOOTING CHART
LED STATUS PROBLEM CORRECTIVE ACTION
0 FLASHES (LED NOT LIT) Pilot light is not lit or 
thermopile has not yet reached 
normal operating temperature.Turn Gas Control Valve/Thermostat knob to 
“OFF”. Wait 10 minutes, then attempt to relight 
Pilot by following the lighting instructions on the 
water heater’s label. Until the thermopile reaches 
its normal operating temperature, the Status Light 
will not blink, even if the Pilot is lit. It may take 
up to 90 seconds of continuous Pilot operation 
before the thermopile reaches normal operating 
temperature and the Status Light starts to blink.
If the Status Light does not blink after three 
lighting attempts, check to make sure unit is 
getting gas. Remove the outer door. Press reset 
button. Replace outer door. Turn Gas Control 
Valve/Thermostat knob to “OFF”. Wait 10 minutes, 
then attempt to light Pilot by following the lighting 
instructions on the water heater’s label. Look 
through the view port for the Pilot flame. If Pilot is 
not visible, the spark igniter or gas supply to the 
Pilot should be checked.
If the Pilot is visible and the Status Light does 
not blink after 90 seconds of continuous Pilot 
operation, the Pilot flame may not be heating the 
thermopile sufficiently (weak Pilot), the thermopile 
may be defective, or wiring connectors may be 
loose.
RED LIGHT ON (SOLID) Pilot light was recently 
extinguished and the 
thermopile is cooling down.Turn Gas Control Valve/Thermostat knob to 
“OFF”. Wait 10 minutes for the thermopile to 
cool, then attempt to relight Pilot by following the 
lighting instructions on the water heater’s label. 
NOTE: This gas control valve/thermostat has 
built-in circuitry that requires waiting 10 minutes 
between lighting attempts.
Until the thermopile reaches its normal operating 
temperature, the Status Light will not blink, even 
if the Pilot is lit. It may take up to 90 seconds of 
continuous Pilot operation before the thermopile 
reaches normal operating temperature and the 
Status Light starts to blink.
1 FLASH (EVERY 3 
SECONDS)Normal operation. No corrective action necessary.
2 FLASHES Pilot is lit but the thermopile 
is not producing the required 
output voltage.Turn Gas Control Valve/Thermostat knob to 
“OFF”. The thermopile is probably defective, but 
loose wiring connections or a weak Pilot flame 
can also cause this symptom. 
						

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LED STATUS PROBLEM CORRECTIVE ACTION
4 FLASHES The Gas Control Valve’s 
temperature sensor has 
detected that the water 
temperature was too high. 
Once this condition occurs, 
the Main Burner and the Pilot 
Light will be shut off. Since the 
Pilot light will be off, should 
this condition occur, this Flash 
Code will only be displayed 
immediately after the Pilot has 
been relit. Turn Gas Control 
Valve/Thermostat knob to 
“OFF”.Relight pilot and verify 4 flashes. If 4 flashes are 
observed, turn Gas Control Valve/Thermostat 
knob to “OFF”. Turn Main Gas Supply “OFF.” 
Replace the Gas Control Valve/Thermostat. See 
“Removing and Replacing the Gas Control Valve/
Thermostat.” 
5 FLASHES The temperature sensor 
(thermistor) is defective.Turn Gas Control Valve/Thermostat knob 
to “OFF”. Replace the temperature sensor 
(thermistor).
7 FLASHES Gas Control Valve failure. Turn Gas Control Valve/Thermostat knob to 
“OFF”. Turn Main Gas Supply “OFF”. 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. 
						

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NOTES 
						

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.com 47
NOTES
  
						

							   
 
 
 
 
 
 
500 Princeton Road, Johnson City, TN 37605
Phone: 800-999-9515  •  Fax: 800-999-5210
www.americanwaterheater.com