A.O. Smith BTH 300A, BTH 400A warranty Operating Instructions, Prior to Start UP Required Ability

PRIOR TO START UP - REQUIRED ABILITY

INSTALLATION OR SERVICE OF THIS WATER HEATER REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS SUPPLY AND ELECTRICAL WORK ARE REQUIRED.

Before attempting start-up, thoroughly study and familiarize yourself with the exact sequence of operation and all other details on the specific heater being used.

The power burner is equipped with an ignition system which automatically sequences prepurge and ignition, senses and ignites main burner flame and sequences burner operation. Heater is equipped with an ignition control which locks out after three unsuccessful ignition attempts. Familiarize yourself with the sequence of operation of this unit prior to start-up.

Be certain that the water heater is full of water, that air is purged from all lines, there are no leaks (gas and water), and all inlet water lines are open.

The following test equipment should be on hand (all test equipment must be acclimated to ambient temperature before calibration and use.)

– Two U-tube manometers or calibration 0-10" W.C. (0-2.5Kpa) and 0-35" W.C. (0-8.7Kpa) pressure gauges.

•Attach a gas pressure gauge or manometer to the upstream side of main gas cock and a gas pressure gauge or manometer to the manifold pressure tap.

•You are now ready to begin the burner start-up procedure.

OPERATING INSTRUCTIONS

IMPORTANT

IT IS RECOMMENDED THAT A QUALIFIED SERVICE TECHNICIAN PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME THE USER SHOULD ASK THE TECHNICIAN ANY QUESTIONS IN REGARD TO THE OPERATION AND MAINTENANCE OF THE UNIT.

CAUTION

BEFORE PROCEEDING WITH THE OPERATION OF THE UNIT, MAKE SURE HEATER AND SYSTEM ARE FILLED WITH WATER AND ALL AIR IS EXPELLED FROM HEATER AND PIPING.

NEVER OPERATE THE HEATER WITHOUT FIRST BEING CERTAIN IT IS FILLED WITH WATER AND A TEMPERATURE AND A PRESSURE RELIEF VALVE IS INSTALLED IN THE RELIEF VALVE OPENING OF THE HEATER. DO NOT ATTEMPT TO OPERATE HEATER WITH COLD WATER INLET VALVE CLOSED.

FILLING:

1.Close the heater drain valve.

2.Open a nearby hot water faucet to permit the air in the system to escape.

3.Fully open the cold water inlet pipe valve allowing the heater and piping to be filled.

4.Close the hot water faucet as water starts to flow.

5.The heater is ready to be operated.

THE MAIN MANUAL GAS SHUTOFF VALVE MUST HAVE BEEN CLOSED FOR AT LEAST FIVE (5) MINUTES. THIS WAITING PERIOD IS AN IMPORTANT SAFETY STEP. ITS PURPOSE IS TO PERMIT GAS THAT MIGHT HAVE ACCUMULATED IN THE COMBUSTION CHAMBER TO CLEAR. IF YOU DETECT GAS AT THE END OF THIS PERIOD, DO NOT PROCEED WITH LIGHTING. RECOGNIZE THAT GAS ODOR, EVEN IF IT SEEMS WEAK, MAY INDICATE THE PRESENCE OF ACCUMULATED GAS SOMEPLACE IN THE AREA WITH A RISK OF FIRE OR EXPLOSION. SEE THE FRONT PAGE FOR STEPS TO BE TAKEN.

DO NOT USE THIS HEATER IF ANY PART HAS BEEN UNDER WATER. IMMEDIATELY CALL A QUALIFIED SERVICE TECHNICIAN TO INSPECT THE HEATER AND TO REPLACE ANY PART OF THE CONTROL SYSTEM AND ANY GAS CONTROL WHICH HAS BEEN UNDER WATER.

LIGHT THE UNIT IN ACCORDANCE WITH THE OPERATING INSTRUCTIONS LABEL ATTACHED TO THE HEATER.

THESE INSTRUCTIONS ARE REPEATED IN THE LIGHTING AND OPERATING LABEL ILLUSTRATION ON PAGE 20 IN THIS MANUAL.

ADJUSTMENT PROCEDURE - INITIAL START-UP

A minimum dynamic gas supply pressure of 5.2" W.C. (1.29 kPa) for Natural Gas and 11" W.C. (2.74 kPa) for LP Gas is required before making any adjustment to the gas control pressure regulator Attempts to adjust the regulator during periods of low gas supply pressure could result in overfiring of the heater when the gas supply pressure returns to normal.

1.Check gas line pressure with a manometer.

2.Check manifold pressure (see Table 4, page 23) using a pressure gauge (manometer) connected to the manifold pressure tap on the gas control valve, (Figure 15).

If full rate adjustment is required, remove cover screw from top of the gas control valve, (Figure 15).

Using a small screwdriver, turn adjusting screw clockwise to increase or counterclockwise to decrease gas pressure to obtain 4.0" W.C. (0.996 kPa) for Natural Gas and 10" W.C. (2.49 kPa) for LP gas.

3.Cycle the burner on and off several times to check its operation.

4.Check the operation of the limit and operating controls.

5.Check the vent system seams and joints and ensure that there is no discharge of flue products into the room.

6.Check the input rate:

For appliance installation locations with elevations above 2000 feet (610 m) refer to HIGH ALTITUDE INSTALLATIONS section of this manual.

a. Attach a pressure gauge (manometer) to the manifold pressure tap (Figure 16) and refer to Table 4, page 20 for correct pressure.

b. Use this formula to “clock” the meter. Be sure other gas consuming appliances are not operating during this interval.

3600	X H = Btuh	3600	X 1050 = 300,000 Btuh (87.9 kW)
T		12.6

T = Time in seconds to burn 1 cubic foot of gas. (With a stopwatch read the gas meter and measure the amount of time required for the heater to consume 1 cubic foot of gas.)

H = Heating value of gas (in Btu’s per cubic foot of gas). Btuh = Actual heater input rate, in Btuh.

EXAMPLE: (Using BTH-300 heater) T = 12.6 seconds

H = 1050 Btu/ft.3 BTUH = ?

For high altitude installations, compare result to the derated input required for the elevation at the installation location.

Should it be necessary to adjust the gas pressure to the burner, to obtain the full input rate, the steps below should be followed:

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