A.O. Smith FMD 40 Water Heater User Manual


 
19
FUEL CONVERSION INSTRUCTIONS
FROM PROPANE (L.P.) GAS TO NATURAL GAS
This water heater has been factory equipped to operate with the
type gas indicated in the “EQUIPPED FOR” area of the model rating
plate located near the gas control valve/thermostat. The indicated
gas may be either Natural or Propane (L.P.). By following the
conversion instructions in this manual or the instructions near the
gas control valve/thermostat, the water heater must be converted if
it is to be used with the opposite gas. DO NOT USE THIS WATER
HEATER WITH ANY GAS OTHER THAN THE ONE LISTED ON
THE MODEL RATING PLATE. Failure to use the correct gas can
cause problems which can result in DEATH, SERIOUS BODILY
INJURY, OR PROPERTY DAMAGE. If you have any questions or
doubts consult your gas supplier or gas company.
To convert from Propane (L.P.) gas to Natural gas, follow the “Fuel”
Conversion Instructions “From Natural Gas to Propane (L.P.) Gas”
section except in Step 5, use ori ce “E”, marked “NAT.”. In Step 6
use pilot ori ce “G”, brass color and in Step 8 turn control screw
“B” in Figure 12 clockwise (
) to stop. Screw must be in “OUT”
position for Natural Gas.
See “Instruction Label” for ori ce sizes and information below.
FOR 30 GALLON HEATER:
Ori ce size: #52 Propane (L.P.) / #40 for Natural ,
if converted - Natural Rate: 30,000 BTU.
FOR 40 GALLON HEATER:
Ori ce size: #51 for Propane (L.P.) / #38 for Natural,
if converted - Natural Rate: 32,000 BTU.
FOR 50 GALLON HEATER:
Ori ce size: #51 for Propane (L.P.) / #35 for Natural,
if converted - Natural Rate: 38,000 BTU.
Maximum Supply Pressure:
10.5” W.C. for Natural Gas.
13” W.C. for Propane (L.P.) Gas.
Minimum Supply Pressure:
5” W.C. for Natural Gas.
11” W.C. for Propane (L.P.) Gas.
FIGURE 32.
FIGURE 33.
FIGURE 34.
FIGURE 30.
FIGURE 31.