Products : Specifications for 15 - 25 Ton Units

EM DE Series 15-25 Tons - Large Commercial DE Series, Patent #6,523,359  

General
Furnish and install where shown on plans, EM Series self-contained packaged air-conditioning dehumidification unit. Capacities, models and unit arrangement shall be as shown on the unit schedule and the contract drawings. Units shall be listed for UL and CUL. Units shall conform to ANSI/UL standard 1995. Each unit shall be completely factory assembled, piped, wired, and tested. Units shall be leak tested and charged with a full operating charge of Refrigerant 22. Installation and maintenance manuals and wiring diagrams shall be supplied with each unit. Factory tested shall include, but not limited to: complete run check of all electrical components and safeties, including proper control sequencing; pressure test of refrigerant coils and condensers; leak check of completed refrigerant circuits; leak check of completed water circuit; compressor run check.

The units shall be designed to operate with entering fluid temperatures between 50°F (10°C) and 110°F (43.3°C) in cooling .

Refrigeration Circuits
All units shall contain sealed refrigerant circuits including hermetic compressors, thermal expansion valve metering devices, finned tube air-to-refrigerant exchangers, refrigerant reversing valves and service ports. Compressors shall be high efficiency, designed for heat pump duty, internally spring isolated (except for scroll type compressors) for maximum sound attenuation and mounted on rubber vibration isolators.

Compressor motors shall be equipped with overload protection. Refrigerant reversing valves shall be pilot operated sliding piston type with replaceable encapsulated magnetic coils energized only during the cooling cycle. The finned tube coil shall be constructed of lanced aluminum fins not exceedi ng fourteen fins per inch bonded to rifled copper tubes in a staggered pattern not less than three rows deep and have a 450 PSIG (3100 kPa) working pressure. The coaxial water-to-refrigerant heat exchangers shall be constructed of a convoluted copper (optional cupronickel) inner tube and steel outer tube with a designed refrigerant working pressure of 450 PSIG (3100 kPa) and a designed water side working pressure of no less than 400 PSIG (2750 kPa).heat.

Casing and Cabinet
Cabinet is available in stainless steel as an option) Galva-LumThe cabinet shall be fabricated from heavy-gauge galvanized steel and aluminum. The interior shall be insulated with ½” (12/7mm) thick, multi density, coated, glass fiber. All units shall allow sufficient service access to replace the compressors without unit removal. Two blower and two compressor compartment access panels shall be removable with supply and return ductwork in place. A duct collar shall be provided on the supply air opening of all vertical units. A 2” (50.8mm) return air filter rack/duct collar with 1” (25.4mm) thick filters shall be provided with each unit. Vertical units shall have an insulated divider panel between the air handling section and the compressor section to minimize the transmission of compressor noise, and to permit operational service testing without air bypass.

Piping
Supply, return water and condensate drain connections shall be copper or brass female pipe thread fittings and mounted flush to cabinet exterior.

Electrical
Controls and safety devices will be factory wired and mounted within the unit. Controls shall include fan relay(s), compressor contractors, 24V transformer, reversing valve coils and a solid state lock-out control circuit which includes diagnostic LED's, low pressure bypass time delay, anti-short cycle time delay and random start time delay. When the safety controls are activated the lock-out circuit must allow one intelligent reset to avoid nuisance trips. Subsequent lock-outs must be reset at the thermostat or main circuit breaker to prevent compressor operation during fault conditions. A lockout indicating terminal shall be provided in the low voltage circuit. Safety devices include a low-pressure cutout set at 20 PSIG (140 kPa) for loss of charge protection (a freeze stat used for loss of charge protection is not acceptable) and a high-pressure cutout control set at 380 PSIG (2600 kPa). An optional condensate overflow switch shall be factory installed to stop compressor operation to prevent drain pan overflow. An optional energy management relay to allow unit control by an external source shall be factory installed.

Fan Moter and Assembly(s)
The fan(s) shall be belt driven DWDI forward curved type with dynamically balanced wheel(s). The housing(s) and wheel(s) shall be designed for quiet low velocity operation. The fan housing(s) shall be removable from the unit without disconnecting the supply air ductwork for servicing of the fan motor(s)

The fan motor(s) shall be 1725 or 3450 RPM 56 frame sealed ball bearing type. The motor(s) shall be permanently lubricated and have thermal overload protection.