A.O. Smith 315795-000 MH, FMD 40, FMD 50, FMD 30 instruction manual For 30 Gallon Heater

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 orifice “E”, marked “NAT.”. In Step 6 use pilot orifice “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 orifice sizes and information below.

FOR 30 GALLON HEATER:

Orifice size: #52 Propane (L.P.) / #40 for Natural ,

if converted - Natural Rate: 30,000 BTU.

FOR 40 GALLON HEATER:

Orifice size: #51 for Propane (L.P.) / #38 for Natural,

if converted - Natural Rate: 32,000 BTU.

FOR 50 GALLON HEATER:

Orifice 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 30.

FIGURE 31.

FIGURE 32.

FIGURE 33.

FIGURE 34.

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