Bryant 583B Heating Inputs, Heating Number GAS Supply Pressure Manifold Pressure, Btuh Orifices

TABLE 6—HEATING INPUTS

HEATING	NUMBER			GAS SUPPLY PRESSURE				MANIFOLD PRESSURE
					(IN. WG)				(IN. WG)
INPUT	OF
			Natural			Propane†
(BTUH)*	ORIFICES
		Min		Max		Min	Max	Natural		Propane†
40,000	2	4.0		13.0		7.0	13.0	3.5		3.5
60,000	2	4.0		13.0		7.0	13.0	3.5		3.5
90,000	3	4.0		13.0		7.0	13.0	3.5		3.5
115,000	3	4.0		13.0		7.0	13.0	3.5		3.5
130,000	3	4.0		13.0		7.0	13.0	3.5		3.5

*When a unit is converted to propane, different size orifices must be used. See separate natural-to-propane conversion kit instructions.

†Based on altitudes from sea level to 2000 ft. above sea level. For altitudes above 2000 ft., reduce input rating 4% for each 1000 ft. above sea level. In Canada, from 2000 ft. above sea level to 4500 ft. above sea level, derate the unit 10%.

3.The induced-draft motor will start.

4.After a call for heating, the main burner should light within 5 seconds. If the burners do not light, there is a 22-second delay before another 5-second try. If the burners still do not light, this sequence is repeated. If the burners do not light within 15 minutes from the initial call for heat, there is a lockout. To reset the control, break the 24-v power to W.

5.The evaporator fan will turn on 45 seconds after the flame has been established. The evaporator fan will turn off 45 seconds after the thermostat has been satisfied.

CHECK GAS INPUT—Check gas input and manifold pressure after unit start-up (see Table 6.) If adjustment is required, proceed as follows:

The rated gas inputs shown in Table 6 are for altitudes from sea level to 2000 ft. above sea level. These inputs are based on natural gas with a heating value of 1050 Btu/ft3 at 0.65 specific gravity, or propane gas with a heating value of 2500 Btu/ft3 at 1.5 specific gravity. For elevations above 2000 ft., reduce input 4% for each 1000 ft. above sea level. When the gas supply being used has a different heating value, or specific gravity, refer to national and local codes, or contact your distributor to determine the required orifice size.

CAUTION: These units are designed to consume the rated gas inputs using the fixed orifices at specified manifold pressures as shown in Table 6. DO NOT

REDRILL THE ORIFICES UNDER ANY CIRCUM- STANCES.

ADJUST GAS INPUT—The gas input to the unit is determined by measuring the gas flow at the meter or by measuring the manifold pressure. Measuring the gas flow at the meter is recommended for natural gas units. The manifold pressure must be measured to determine the input of propane gas units.

MEASURE GAS FLOW (Natural Gas Units)—Minor adjustment to the gas flow can be made by changing the manifold pressure. The manifold pressure must be maintained between 3.4 and 3.6 in. wg. If larger adjustments are required, change main burner orifices following the recommendations of national local codes.

NOTE: All other appliances that use the same meter must be turned off when gas flow is measured at the meter.

Proceed as follows:

1.Turn off gas supply to unit.

2.Remove pipe plug on manifold (see Fig. 16) then connect manometer at this point. turn on gas to unit.

3.Record number of seconds for gas meter test dial to make one revolution.

4.Divide number of seconds in Step 3 into 3600 (number of seconds on one hour).

5.Multiply result of Step 4 by the number of cu. ft. shown for one revolution of test dial to obtain cu. ft. of gas flow per hour.

6.Multiply result of Step 5 by Btu heating value of gas to obtain total measured input in Btuh. Compare this value with heating input shown in Table 6. (Consult the local gas supplier if the heating value of gas is not known.)

EXAMPLE: Assume that the size of test dial is 1 cu. ft., one revolution takes 32 seconds, and the heating value of the gas is 1050 Btu/ft3.

Proceed as follows:

1.32 seconds to complete one revolution.

2.3600 ⎟ 32 = 112.5

3.112.5 x 1 = 112.5 ft3 of gas flow/hr.

4.112.5 x 1050 = 118,125 Btuh input.

If the desired gas input is 115,000 Btuh, only a minor change in the manifold pressure is required.

MANIFOLD PIPE PLUG

C99019

Fig. 16—Burner Assembly

Observe manifold pressure and proceed as follows to adjust gas input:

1.Remove cover screw over regulator adjustment screw on gas valve.

2.Turn regulator adjustment screw clockwise to increase gas input, or turn regulator adjustment screw counterclockwise to decrease input. Manifold pressure must be between 3.4 and 3.6 in. wg.

WARNING: Unsafe operation of the unit may result if manifold pressure is outside this range. Serious injury or unit damage may result.

3.Replace cover screw cap on gas valve.

4.Turn off gas supply to unit. Remove manometer from pressure tap and replace pipe plug on gas valve. Turn on gas to unit and check for leaks.

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