2.5.1.3
Motor
Compressor motors shall be of the constant-speed, squirrel-cage, induction,
hermetically sealed, low-starting-current, high-torque type. Motors shall
be furnished with magnetic NEMA across-the-line motor starters in general
purpose enclosures.
2.5.1.4
Compressor Components
Compressor systems shall include, as a minimum, the following:
a.
Compressors 1.1 kW 1-1/2 hp and larger shall be provided with
double seated suction and discharge service valves each with gauge
ports.
b.
Compressors 3.7 kW 5 hp or larger shall have a solid state oil
pressure safety switch with a manual reset with auxiliary alarm
contacts. Time delay duration shall be as recommended by
compressor manufacturer.
c.
Each compressor shall have a single low-pressure control with
automatic reset and adjustable cut-in and cut-out range. Braided
steel lines shall be used.
d.
Each compressor shall have a single high-pressure control with
manual reset, adjustable set-point, and auxiliary alarm contact.
Braided steel lines shall be used.
e.
A compressor cooling fan shall be provided for each compressor
which operates below minus 18 degrees C 0 degrees F saturated
suction temperature.
f.
Each compressor shall have a crankcase oil heater. Control of the
heaters shall be as recommended by the compressor manufacturer.
g.
When required by the compressor manufacturer, compressors shall be
provided with a hot-gas muffler to reduce vibration and noise from
pulsations.
2.5.2
Base Mounting
**************************************************************************
NOTE: Where condensing units or compressors are
located on top of walk-in boxes, mount on spring
vibration isolators. Mass of inertia block shall be
an engineered solution accommodating site conditions.
**************************************************************************
Compressor and accommodating components shall be factory mounted on a
rigid, steel [base,] [rack,] where indicated. Compressor assembly shall be
mounted [with spring type vibration isolation mountings [. Elastomer pads
shall placed between the assembly base and the floor.] [selected to limit
transmissibility of imbalanced forces at lowest equipment rpm to 5
percent.]] [on a concrete inertia block, fitted with spring type vibration
isolation mountings. Mass of the concrete inertia block shall be [2.0]
[_____] times mass of supported assembly. Spring mountings shall be
selected to limit transmissibility of imbalanced forces at lowest equipment
rpm to 3 percent.]
SECTION 15652A
Page 19
Previous Page
