95
d. Shall have superi or hardness characteristics of 2H per ASTM D3363--00 and cross--hatch adhesion of 4B--5B
per ASTM D3359--02.
e. Shall have superior im pact resistance with no cracking, chipping or peeling per NSF/ANSI 51--2002 Method
10.2.
23 81 19.13.K. Refrigerant Components
1. Re frigerant circui t shall include the following control, safety, and maintenance feature s:
a. Fixed orifice metering system shall prevent mal--distribution of two--phase refrigerant by including multiple
fixed orifice devices in each refrigeration circuit. Each orifice is to be optimized to the coil circuit it serves.
b. Refrigerant filter drier.
c. Service gauge connections on suction and discharge lines.
d. Pressure gauge access through a specially designed access port in the top panel of the unit.
2. There shall be gauge line access port in the skin of the rooftop, covered by a black, removable plug.
a. The plug shall be easy to remove and replace.
b. When the plug is removed, the gauge access port shall enable maintenance personnel to route their pressure
gauge l ines.
c. This gauge access port shall facilitate correct and accurate condenser pressure readings by enabling the read-
ing with the compressor access panel on.
d. The plug shall be made of a leak proof, UV--resistant, composite mate rial.
3. Compressors
a. Unit shall use one fully hermetic, scroll compressor for each independent refrigeration circuit.
b. Models shal l be ava ilabl e with single compressor designs on 04--12 models, plus additional 2 c ompressor
(stage) models from 08--14 sizes with NOVATIONt condenser coils.
c. Compressor motors shall be cooled by refrigerant gas passing through motor windings.
d. Compressors shall be internally protecte d from high discharge te mperat ure conditions.
e. Compressors shall be protected from an over--temperature and over--amperage conditions by an internal, motor
overload device.
f. Compressor shall be factory mounte d on rubber grommets.
g. Compressor motors shall have internal line break the r mal, current overload and high pressure differentia l pro-
tection.
h. Cra nkcase heaters shall not be required for normal operating range, unless provided by the factory.
23 81 19.13.L. Filter Section
1. Filters access is specified in the unit cabinet section of this specification.
2. Filters shall be held in place by a pivoting filter tray, facilitating easy removal and installation.
3. Shall consist of factory--installed, low velocity, throw--away 2--in. thick fiberglass filters.
4. Filters shall be standard, commercially available sizes.
5. Only one size filter per unit is allowed.
23 81 19.13.M. Evapora tor Fan and Motor
1. Evaporator fan motor:
a. Shall have permanently lubricated bearings.
b. Shall have inherent automatic --reset thermal overload protection or circuit breaker.
c. Shall have a maximum c ontinuous bhp rating for continuous duty operation; no safety factors above that rating
shall be required.
2. Be lt--dri ven Evaporator Fan:
a. Belt drive shall include an adjustable--pitch motor pulley.
b. Shall use sealed, permanently lubricated ball --bearing type.
c. Blower fan shall be double--inlet type with forward--curved blades.
d. Shall be constructed from ste el with a corrosion resistant finish and dynamical ly balanced.
23 81 19.13.N. Condenser Fans and Motors
1. Conde nser fan motors:
a. Shall be a totally enclosed motor.
b. Shall use permanently lubricated bearings.
c. Shall have inherent thermal overload protection with an automatic reset feature.
d. Shall use a shaft--down de sign on 04 to 12 models and shaft--up design on 14 size with rain shiel d.
2. Conde nser Fans:
50TC
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