Gas Valves; Checking The Input; Venting System; Remote Storage Tank Temperature Control - A.O. Smith BTI 120 Installation & Operation Manual

NOTE:
1. Remove main burners from unit.
2. Check that burner venturi and ports are free of foreign debris.
3. Clean burners with bristle brush and/or vacuum cleaner
- DO NOT distort burner ports or pilot location.
4. Reinstall burners in unit. Make sure front and rear of burners
are installed correctly in burner support brackets.
Also check for good flow of combustion and ventilating air to the
unit. Maintain a clear area around the heater at all times.

GAS VALVES

Figure 14 shows the type of combination manual gas control
valve and regulator used on these heaters.
If the gas valve becomes defective, repairs should not be
attempted. A new valve should be installed in place of the
defective one.
FIGURE 14

CHECKING THE INPUT

For appliance installation locations with elevations above
2000 feet, refer to HIGH ALTITUDE INSTALLATIONS section of
this manual for input reduction procedure.
1. Attach a pressure gauge or a manometer to the gauge port
and refer to Table 4, for correct manifold pressure.
2. Use this formula to "clock" the meter. Be sure that other gas
consuming appliances are not operating during this interval.
3600 X H = Btuh
T
T = Time in seconds to burn one cubic foot of gas.
H = Btu's per cubic foot of gas.
Btuh = Actual heater input.
Example: (Using BTI-250 heater)
T = 15.1 seconds
H = 1050 Btu
Btuh = ?
36.8 X 1050 = 250,000 Btuh (Compare with the BTI 250
model and rating.)
Should it be necessary to adjust the gas pressure to the burners
to obtain the full input rate, the steps below should be followed:
3. Remove the regulator adjustment sealing cap, fig. 14, and
adjust the pressure by turning the adjusting screw with a
screwdriver.
Clockwise to increase gas pressure and input rate.
Counterclockwise to decrease gas pressure and input
rate.
4. "Clock" the meter as in step 2 above.
5. Repeat steps 3 and 4 until the specified input rate is achieved.
6. Turn the gas control knob to PILOT. Remove the pressure
gauge and replace the sealing cap and the allen wrench set
screw in the pressure tap opening.
UNDER NO CIRCUMSTANCES SHOULD THE GAS INPUT
EXCEED THE INPUT SHOWN ON THE HEATER MODEL AND
RATING PLATE. OVERFIRING COULD RESULT IN DAMAGE OR
SOOTING OF THE HEATER.
When the heater is operating at full capacity, or full gas input, it
should consume 1 cu. ft. of gas in time indicated on Table 5.

VENTING SYSTEM

Examine the venting system every six months for obstructions
and/or deterioration of the vent piping.
Remove all soot or other obstructions from chimney which will
retard free draft.
REMOTE STORAGE TANK
TEMPERATURE CONTROL
The water temperature in the storage tank (if used) is controlled
by the storage tank temperature control. The sensing element
is mounted in the hot water storage tank, see page 16.
A change in water temperature in the storage tank lower than the
tank temperature control setting will cause the sensor to activate
the circulating pump. The pump then circulates the water through
the heater where the thermostat senses the drop in water
temperature and activates main burner operation of the appliance.
If the storage tank temperature control is out of calibration, replace
with new control.
SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL
TO SHUT OFF, TURN OFF THE MANUAL GAS CONTROL VALVE
TO THE APPLIANCE.

RELIEF VALVE

At least once a year, the temperature and pressure relief valve
should be checked to ensure that it is in operating condition. Lift
the lever at the top of the valve several times until the valve seats
properly and operates freely.
26
WARNING
WARNING