A.O. Smith XDVS - Manual (Page 23)

23
TROUBLESHOOTING
Please check guidelines below. For your safety, water heater service should be performed only by a qualified service technician.
Read the GENERAL SAFETY INFORMATION section first.
PROBLEM POSSIBLE MALFUNCTION SERVICE TO BE PERFORMED POSSIBLE SOLUTION
NO HOT WATER 1) No pilot
A. No gas to pilot Check gas supply Turn on, check pressure
Check gas valve Turn on or replace if needed
Check pilot orifice for obstruction Clean with air or replace
Check pilot tube for kink or leaks Replace pilot tube
B. Pilot will not stay lit Check gas pressure
Check thermostat MV drop-out voltage
Check thermocouple connection and
Tighten if loose, replace
MV output as necessary
Check thermocouple placement in pilot flame 3/8- should be in flame
Check pilot for proper flame Change pilot orifice
Check ECO operation Replace gas valve
Check for air in pilot tube Bleed as necessary
C. Pilot blows out Leaking joints Check all vent joints for proper seal.
Make sure to check inner and outer
pipe and check rear air tube seals.
Refer to installation manual.
Check for proper vent cap Install A. O. Smith provided vent cap
Check for bent, missing, or mislocated
pilot shield (natural gas units only)
Replace or reposition
Check outer door seal Replace gasket if missing
Tighten screws if loose
Install gasket properly if misinstalled
NOT ENOUGH 1) Incorrect burner orifice Check orifice size Replace with correct size
HOT WATER 2) No gas to main burner Check gas supply Correct as needed
Check thermostat operation Replace as needed
3) Heater too small Confirm sizing requirements Replace with larger heater, add
another heater, or decrease
water usage.
YELLOW FLAMES 1) Excessive or low gas Check gas pressure
OR SOOT pressure
2) Combustion air restricted
Check vent for restrictions Correct as necessary
Check venting for extra piping Re-install as recommended in
the installation manual
CONDENSATION 1) Water on floor under heater See page 21 “CONDENSATION”
BURNER WILL 1) Low gas pressure Check gas supply pressure
NOT STAY LIT Check thermostat operation
2) Downdraft or Check for proper vent cap Install proper vent cap
backdraft condition Check location of heater Re-install in correct location
Check for proper vent sealing Reseal venting
Check top and/or bottom air supply Seal as necessary
box for air leaks
Check outer door seal
Replace gasket, tighten screws
or re-install gasket as necessary