A.O. Smith XDVS User Manual

23

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.

  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