UL 921-2016 pdf download

UL 921-2016 pdf download.Commercial Dishwashers.
7.7.3 To determine whether a dishwasher complies with 7.7.1. the mechanical arrangement shall be such that the movable member operates at a rate of 12 cycles per minute. The movable member shall be operated so that it reaches the actual limits of travel in both directions during each cyde. When requested by the manufacturer, increasing the cycling rate complies with this requirement.
7,7.4 The test on a suppiy-cord reel normally shall be performed with the supply cord not connected to the power-supply receptade. Unreeling of the cord shall be arranged so that there is a maximum tendency to abrade the cord insulation and to wear paris in contact with the cord. A length of 760 mm (30 In) or more of the cord shall be unreeled during the test, and recoiled on the reel automatically. Disengaging the latching mechanism to facilitate conducting the test meets the intent of this requirement. During the test. the tension on the cord shall be applied in the same direction as the direction applied when the cshwasher is being used as intended.
7.8 Insulation resistance following humidity condItioning test
7.8.1 A dishwasher or part of a dishwasher employing insulating material that has the potential to be adversely affected by moisture under conditions of normal operation shall have an insuLation resistance of 50000 1 or more between current-carrying parts and exposed dead-metal parts after exposure for 24 hours to moist air having a relative humidity of 80 —90 percent at a temperature of 30 — 34°C (86 — 93°F). See 4.11.2.
7.8.2 Typically, insulation resistance is measured by a high-resistance voltmeter using a 250-V crect current potential. However, the use of other resistance-measuring equipment p4’oviding equivalent results complies with the requirements.
7.9 Water exposure tests
7.9.1 Water spillage test
7.9.1.1 After a dishwasher has been tested In accordance with 7.9.1.2 for a counterlop or an under-counter type:
a) there shall not be water in a compartment that houses field-installed wiring;
b) there shall not be wetting of any uninsulated live part elsewhere in the dishwasher:
c) the insulation resistance shall not be less than 50,000 L and
d) the dishwasher shall comply with Dielectnc voltage-withstand test, Clause 7.6.
7.9.1.2 A countertop er an under-counter dishwasher shall be leveled, and one pint of water shall be poured from a height 01152 mm (6 in) above the area being tested.
7.9.2 Water spray test
7.9.2,1 After a dishwasher, other than a countertop or under countertop type. has been tested in accordance with 7.9.2.2 — 7.9.2.5 for any other type:
a) there shail not be water in a compartment that houses field-installed wiring:
b) there shall not be wetting of any uninsulated live part elsewhere in the dishwasher; C) the insulation resistance shall not be less than 50,000 ); and
d) the dishwasher shall compty with Dielectric voltage-withstand test, Clause 7,6.
7.9.2.2 The dishwasher, at room temperature, shall be set up in the intended manner with feed and cscharge tables in place. The test shall be periomied with the side panels removed for side panels of the enclosure mat are:
a) removable without the use of tools, unless the dishwasher is marked in accordance with 14.19; or
b) provided as additonal equment by the manufacturer.
79.2.3 An opening that is closed after installation by a water line, a steam line, a drain line, an electric conduit, or similar part or structure shall be closed to simulate normal conditions of use.
7.9.2.4 A hose having the free end fitted with a nozzle as illustrated in Figure 7, Nozzle, shall be connected to a water supply capable of maintaining a 110w rate of 19 Lfmin (5 gaL/mm) as measured at the outlet orifice of the nozzle. The water shall be directed as specified in (a) and (b) at the portion of the enclosure containing electrical components. The nozzle shall not be brought closer than 3.05 m (10 ft) horizontally from any part of the dishwasher. The water from the hose shall be sprayed from all sides and at any angle.