Smith Cast Iron Boilers GVIOM-5R manual Checking & Adjustment

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GV100W BOILER

INSTALLATION & OPERATING INSTRUCTIONS

CHECKING & ADJUSTMENT

Gas Pressure Adjustment

Natural Gas Optimum results are obtained when the boiler is operated at its full input rating, with 3.5 in, 89 mm, WC of manifold pressure. The manifold pressure should not be more that 5% off this value. The gas valve pressure regulator has been preset at the factory. If adjustment is necessary the following steps must be followed.

1.Attach a manometer to the pressure tap on the gas valve body.

2.Remove the regulator adjustment screw cap from the gas valve body.

3.Rotate the regulator adjustment screw clockwise to increase the manifold pressure, counterclockwise to decrease it. Never force the regulator adjustment screw or the gas valve will be damaged!

4.Replace the regulator adjustment screw cap and pressure tap plug.

Propane Gas A manifold pressure of 10.0 in, 254 mm, WC must be maintained for proper operation of the boiler. If the manifold pressure is off by more than 5% adjust it according to steps 1 through 4 above.

Input Rate

Gas appliances are rated based on sea level operation with no adjustment required at elevations up to 2000 ft, 610 m. At elevations above 2000 ft, 610 m, input ratings should be reduced by 4% for each 1000 ft, 305 m, above sea level. Check the input rate as follows:

If the computed rate deviates by more than 5% from the rated input value of the unit adjust the gas valve pressure accordingly. Do not adjust the manifold pressure by more than 5%. If a proper rate cannot be maintained without adjusting the manifold pressure beyond the 5% limit, the main burner orifices must be replaced. If the input rate is too low, go to the next larger size orifices. If the input rate is too high, go to the next smaller size.

Propane Gas

The input rate for LP units is factory set based on the orifice size. The manifold pressure must be set at 10" WC and the #54 burner orifices used unless the unit is to be derated for altitude.

CAUTION: Never increase the input to the boiler above that for which it is rated. Doing so can cause premature failure of the boiler.

FIG. NO. 18 Main Burner Flames

NORMAL	LIFTING
(HARD FLAME)	(TOO MUCH AIR)

YELLOW TIPPING	YELLOW FLAME
(MARGINAL)	(TOO LITTLE AIR)

Natural Gas

1.Turn off all other gas appliances that use the same gas meter as the boiler.

2.Call the gas company for the gas heating value.

3.Start the boiler and let it run for 15 minutes.

4.Using the gas meter and a stop watch, clock the time that it takes to burn 10 cubic feet of gas and divide the time by 10.

5.Insert the heating value and the time, in seconds, into the following formula.

Input Rate = Heating Value(Btu/ft3)(3600 s/hr)

Flow Rate(s/ft3)

Example:

If the heating value = 1000 Btu/ft3 and the flow rate = 36 s/ft3

Input Rate = (1000 Btu/hr)(3600 s/hr) 36 s/ft3

Input Rate = 100,000 Btu/hr

WARNING: Yellow, flooating flames indicate a lack of combustion air. Do not operate the boiler until the problem is solved or severe personal injury or death may occur!

Low Water Cutoff

If the boiler is equipped with a low water cutoff device make sure that the main burners will NOT light when the boiler has no water in it. To check, turn the boiler off, close the valves in the water supply and return lines and drain the boiler. If the boiler’s main burners light shut the boiler off immediately and correct the problem.

Thermostat Adjustment

For a thermostat that employs an adjustable heat anticipator, adjust the anticipator to match the current measured in the thermostat circuit. An increased anticipator setting may be necessary if the unit cycles frequently. If the room temperature over-shoots the thermostat setting, reduce the anticipator setting.