Scope This Standard establishes methods of testing and rating gas-fired, heat pumps for space-conditioning performance. The procedures apply to factory-made, space-conditioning, unitary heat pumps which utilize gas as the primary fuel. This includes engine-driven heat pumps, absorption-cycle heat pumps, desiccant-type heat pumps, and other gas-fired heat pumps. The heat source/sink for the heat pumps may be outdoor air, ground water, or closed-loop water. The heat pumps provide the functions of year-round space conditioning either by direct heating and cooling of air or indirectly by the production of heated and chilled water. The heat pump may include other functions. Appropriate portions of this standard can be applied to heat pumps which have a gas input that varies so that the output matches the cooling or heating load, to heat pumps which have a single level gas input which varies as a function of ambient conditions, and to heat pumps which have a constant gas input regardless of load or ambient conditions, and to heat pumps with several discrete levels of gas input. In addition to applying to heat pumps which provide year-round space conditioning, portions of this standard can be applied to heat pumps which provide space cooling only or space heating only. Also, procedures are provided for testing and rating water-cooled air conditioners and water-cooled chillers which reject condenser heat with a cooling tower, air- and water-cooled condensing units, and desiccant ventilation-air dehumidifiers. Section 2 lists the thermal testing that is required for each class of appliance. The type of test and the levels of gas input are prescribed. For air-source/sink appliances, the outdoor temperature conditions are specified, and for water-source/sink appliances, the entering source/sink water temperatures are specified. Section 3 identifies additional conditions at which the thermal tests specified in Section 2 are to be conducted. This includes the voltage of auxiliary electric input, indoor air quantities, return air temperatures, water flow rates, and return water temperatures. Section 4 outlines the procedures to be followed when thermal testing. This includes steady-state tests and cyclic tests for the cooling mode, and steady-state tests, cyclic tests, and frost accumulation tests for the heating mode. Section 5 covers calculation procedures for determining steady-state capacity and input ratings for the appliance operating in the cooling mode. Appropriate adjustments are made to the input and output values determined by the tests to normalize the impacts of auxiliary electric inputs. Section 6 covers calculation procedures for determining steady-state capacity and input ratings for the appliance operating in the heating mode. Appropriate adjustments are made to the input and output values determined by the tests to normalize the impacts of auxiliary electric inputs. The next four sections of the standard cover calculation procedures for determining seasonal and annual performance parameters for residential and commercial applications. Section 7 covers calculation procedures for determining cooling-mode seasonal output and energy consumption ratings for appliances suitable for installation in residential applications. The steady-state cooling ratings from Section 5 are required as inputs for these determinations. A sample calculation is provided in Annex A. Section 8 covers calculation procedures for determining heating-mode seasonal output and energy consumption ratings for appliances suitable for installation in residential applications. The steady-state heating ratings from Section 6 are required as inputs for these determinations. A sample calculation is provided in Annex B. Section 9 covers calculation procedures for determining annual energy consumption for appliances suitable for installation in residential applications. The seasonal energy consumption data determined in Sections 7 and 8 are required as inputs for these calculations. Section 10 covers calculation procedures for determining cooling-mode average hourly output and energy consumption ratings for appliances suitable for installation in commercial applications. The steady-state cooling ratings from Section 5 are required as inputs for these determinations. A sample calculation is provided in Annex C. Section 11 covers procedures for determining outdoor sound power level ratings for air-source appliances. Section 12 lists the references used in developing the standard.