Coils shall have [nonferrous] [copper or aluminum] tubes of 10 mm 3/8 inch
minimum diameter with copper or aluminum fins that are mechanically bonded
or soldered to the tubes. Coils shall be protected with a minimum 0.076 mm
3 mil thick [phenolic] [or] [vinyl] coating. Casing shall be galvanized
steel or aluminum. Contact of dissimilar metals shall be avoided. Coils
shall be tested in accordance with ASHRAE 15 at the factory and be suitable
for the working pressure of the installed system. Each coil shall be
dehydrated and sealed after testing and prior to evaluation and charging.
Each unit shall be provided with a factory operating charge of refrigerant
and oil or a holding charge. Unit shipped with a holding charge shall be
field charged. Separate expansion devices shall be provided for each
compressor circuit.
2.11.1.2
Fan Section
Fan shall be the [centrifugal] [propeller] type in accordance with
paragraph "Fans". Motors shall have [open] [dripproof] [totally enclosed]
[explosion proof] enclosures and be suitable for the indicated service.
2.11.1.3
Pump
Pump and controls shall be mounted within a lockable sheet metal enclosure
supported from dry cooler structure. Pump shall be of the end-suction type
with an [open] [dripproof] [totally enclosed] [explosion proof] motor.
Pump construction shall be as specified in paragraph "Pumps". Seals shall
be mechanical type suitable for ethylene glycol solution up to a 60 percent
concentration of glycol, and be rated for 82 degrees C 180 degrees F
service.
2.11.1.4
Controls
The control system shall be complete with all required accessories for
regulating glycol temperature by [fan cycling.] [solid-state variable fan
speed.] [modulating glycol 3-way mixing valve or modulating fan dampers.]
Unit-mounted control panels or enclosures shall be constructed in
accordance with applicable requirements of NFPA 70 and housed in NEMA ICS 6,
Class 1 or 3A enclosures. Controls shall include a [control transformer,]
[fan motor [starters,]] [solid-state speed control,] [pump motor starters,]
[electric heat tracing controls,] [time delay start-up,] overload
protective devices, interface with local and remote components, and
intercomponent wiring to terminal block points.
2.11.2
Humidifier
2.11.2.1
Steam Spray Type
Steam spray humidifiers shall inject steam directly into the [surrounding
air] [or] [air stream]. [Single grid humidifiers shall consist of a single
copper distribution grid with pipe connection on one end and cap on the
other end. Automatic steam control valves and condenser traps shall be
field-installed.] [Enclosed grid shall be housed in a copper enclosure
with a built-in condensate drain connection. Exposed grid shall be wick
wrapped.] [Package type steam spray humidifiers shall be equipped to trap
out and to evaporate condensate and to supply dry steam to a single
distribution grid. Grid shall be steam jacketed and condensate drained.
Unit shall trap excess condensate to return system. Package type steam
spray humidifiers shall have modulating electric, electronic, or pneumatic
steam control valve, as indicated.] Steam spray humidifiers shall be rated
for humidifying capacity in pounds of steam per hour and at steam pressure
SECTION 15700A
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