6.1.3

Distribution of Actual Cooling Load Hours (CLH) Throughout the United States

1Test operating tolerance is the maximum permissible variation of any measurement. When expressed as a percentage, the maximum allowable variation is the specified percentage of the average value. Test Operating Tolerance During Heating applies when the heat pump is in the heating mode, except for the first 5 minutes after termination of a defrost cycle. Test Operating Tolerance During Defrost applies during a defrost cycle and during the first 5 minutes after the termination of a defrost cycle when the heat pump is operating in the heating mode.

2 Test condition tolerance is the maximum permissible variation of the average value of the measurement from the standard or desired test condition. Test Condition Tolerance applies only when the heat pump is operating in the heating mode.

3 Not applicable during defrost if the indoor fan is off.

6.2.4 Distribution of fractional hours in temperature bins, heating load hours and outdoor design temperature for the different climatic regions.

Entering..

2.0

Leaving.

Entering

Leaving.

Indoor wet-bulb, F:

1.0

00

Outdoor dry-bulb, F:

Entering

2.0

Leaving.

Outdoor wet-bulb, F:

Entering.

20

2.0

Leaving

External resistance to air-flow,

Actual heating load hours (HLH) and regional heating load hours (HLHR for the United States

III

TX

This map is reasonably accurate fur most parts of the United States but is necessarily highly generalized and consequently not too accurate in mountainous regions, particularly in the Rockies.

APPENDIX N TO SUBPART B OF PART 430-UNIFORM TEST METHOD FOR MEASURING THE ENERGY CONSUMPTION OF FURNACES

1. Definitions. Definitions shall include the definitions specified in section 3.0 of ANSI/ASHRAE 103-82 and the following additional definitions:

1.1 "ASHRAE" means the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

1.2 "ANSI/ASHRAE 103-82" means the test standard published in 1982 by ASHRAE, approved by the American National Standards Institute (ANSI) on June 21, 1983 and titled "Methods of Testing for Heating Seasonal Efficiency of Central Furnaces And Boilers."

1.3 "Electro-mechanical stack damper" means a type of stack damper which is operated by electrical and/or mechanical means.

1.4 "Isolated combustion system" means an installation in which a furnace is installed indoors and all combustion and ventilation air is admitted through grills or ducts from outdoors and (all such air) does not communicate with air in the conditioned space.

1.5 "Modulating control" means either a step modulating or a “two-stage control"

1.6 "Reduced heat input rate” means the factory adjusted lowest reduced heat input rate for furnaces equipped with either two stage thermostats or step-modulating thermostats.

1.7 “Single stage thermostat” means a thermostat that cycles a burner from the maximum heat input rate and off.

1.8 "Step-modulating control" means a modulating control that cycles a burner from the reduced input rate to off if the heating load is light. If a higher heating load is encountered which cannot be met with the reduced input rate, the control either gradually increases or steps up the input rate to meet the higher heating load. At that point if a lower heating load is encountered, the control either gradually decreases or steps down to a lower rate, or gradually increases the heat input to meet any higher heating load that cannot be met with the low firing rate.

1.9 "Thermal stack damper" means a type of stack damper which is dependent for operation exclusively upon the direct conversion of thermal energy of the stack gases into closure of the damper.

1.10 "Two stage control" means a modulating control that cycles a burner from reduced heat input rate and off or cycles a burner at the maximum heat input rate and off.

2.0 Testing conditions. The testing conditions shall be as specified in section 8 of ANSI/ASHRAE 103-82 with the exception of section 8.4.2.3, and the inclusion of the following additional testing conditions:

2.1 Gas burner adjustment at maximum input rate. The following paragraph is in addition to the requirements specified in section 8.4.1.1 of ANSI/ASHRAE 103-82: For gas fueled furnaces and boilers equipped with modulating type controls, adjust the controls to operate the unit at the maximum fuel input rate. Set the thermostat control to the maximum setting. Start the furnace or boiler by turning the safety control valve to the "on" position. Use a supply water temperature for boilers that will allow for continuous operation without shut off by the thermostat control.

2.2 Gas burner adjustment at reduced input rate. The following paragraph is in addition to the requirements specified in section 8.4.1.1 of ANSI/ASHRAE 103-82:

For gas fueled furnaces and boilers equipped with modulating type thermostat controls, adjust the controls to operate the unit at the reduced fuel input rate. Set the thermostat control to the lowest setting that does not cause the burner to cycle on and off. Start the furnace or boiler by turning the safety control valve to the "on" position. Use supply water temperature for boilers that will allow for continuous operation without shut off by the thermostat control. If necessary, supply water may be increased above 120° F in order to maintain continuous operation at the reduced setting.

2.3 Gas and oil fueled low pressure steam and hot water boilers (including direct vent