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Фрагмент инструкции
E. Unit shall have a suction line accumulator. 4. Unit Controls: A. Unit shall be complete with self contained low--voltage control circuit protected by a resetable circuit breaker fuse on the 24 volt transformer side. B. Unit shall incorporate a lock--out circuit which provides reset capability at the space thermostat or base unit, should any of the following standard safety devices trip and shut off compressor: Unitary Products Group 036-21564-003-A-1005 (1) --Loss--of--charge/Low--pressure switch. (2) --High--pressure switch. If any of the above safety devices trip, an LED (light emitting diode) indicator shall illuminate. C. Unit shall incorporate “AUTO RESET” compressor over--temperature, over--current protection. D. Unit shall operate with conventional thermostat designs and have a low voltage terminal strip for easy hook--up. E. Unit shall have freeze--protection thermostat on evaporator coil. F. Unit shall incorporate an ambient compensated, time and temperature defrost control. (1) --Defrost shall be initiated on the basis of time and liquid line temperature. (2) --A50/80/110--minute timer shall activate defrost cycle only if liquid line temperature is low enough to indicate a heavy frost condition. (3) --Defrost cycle shall terminate when liquid line sensor is satisfied and shall have a positive termination time of 10 minutes. ELECTRIC HEATING SECTION 1. An electric heating section, with nickel chromium elements, shall be provided in a range of 5 thru 30 KW, offering two stages of capacity --16 KW and above on 208/230 volt heaters and 20 KW and above on 460 and 575 volt heaters. 2. The heating section shall have a primary limit control(s) and automatic reset, to prevent the heating element system from operating at an excessive temperature. 3. The Heating Section assembly shall slide out of the unit for easy maintenance and service. 4. Units with Electric Heating Sections shall be wired for a single point power supply with branch circuit fusing (where required). UNIT OPERATING CHARACTERISTICS 1. Unit shall be capable of starting and cooling at 125° F outdoor temperature, exceeding maximum load criteria of ARI Standard 210/240. 2. The compressor, with standard controls, shall be capable of cooling down to 45° F outdoor temperature. ELECTRICAL REQUIREMENTS All unit power wiring shall enter unit cabinet at a single factory provided location and be capable of side or bottom entry, to minimize roof penetrations and avoid unit field modifications. Separate side and bottom openings shall be provided for the control wiring. STANDARD LIMITED WARRANTIES Compressor--5 Years Elect. Heat. Elem.--5 Years Parts --1 Year OPTIONAL OUTDOOR AIR (Shall be made available by either/or): 1. ELECTRONIC ENTHALPY AUTOMATIC ECONOMIZER --Outdoor and return air dampers that are interlocked and positioned by a fully--modulating, spring-return damper actuator. The maximum leakage rate for the outdoor air intake dampers shall not exceed 2% when dampers are fully closed and operating against a pressure differential of 0.5 IWG. A unit--mounted potentiometer shall be provided to adjust the outdoor and return air damper assembly to take in CFM of outdoor air to meet the minimum ventilation requirement of the conditioned space during normal operation. During economizer operation, a mixed--air temperature control shall modulate the outdoor and return air damper assembly to prevent the supply air temperature from dropping below 55°F. Changeover from compressor to economizer operation shall be provided by an integral electronic enthalpy control that feeds input into the basic module. The outdoor intake opening shall be covered with a rain hood that matches the exterior of the unit. Water eliminator/filters shall be provided. Simultaneous economizer/compressor operation is also possible. Dampers shall fully close on power loss. 2. DUAL INPUT DIFFERENTIAL ELECTRONIC ENTHALPY AUTOMATIC ECONOMIZER --Outdoor and return air dampers that are interlocked and positioned by a fully--modulating, spring--return damper actuator. The maximum leakage rate for the outdoor air intake dampers shall not exceed 2% when dampers are fully closed and operating against a pressure differential of 0.5 IWG. A unit mounted potentiometer shall be provided to adjust the outdoor and return air damper assembly to take in the design CFM of outdoor air to meet the minimum ventilation requirement of the conditioned space during normal operation. During economizer operation, a mixed--air temperature control shall modulate the outdoor and return air damper assembly to prevent the supply air temperature from dropping below 55°F. Changeover from compressor to economizer operation shall be provided by two integral electronic enthalpy controls --one that senses outdoor air and one that senses indoor air. Both enthalpy sensors supply input to the logic module which modulates both sets of dampers for maximum economizer savings. The outdoor intake opening shall be covered with a r...