Roberts Gorden Combat IDF-Series - Manual (Page 4)

2.6 FANS AND MOTORS
A. Fan: Th e fan(s) shall consist of centrifugal, [forward curved]
[backward inclined or air foil] double-width, double-inlet
(DWDI) blower wheels and scrolls. Th
e blower assembly
shall be dynamically balanced. Blower shaft s shall be of
tubular design. Th
e shaft s shall not pass through their fi rst
critical speed when the unit comes up to the rated RPM.
Shaft shall be coated with a rust inhibitor.
B. Drive: All V-belt drives shall be standard capacity, with
reinforced rubber belts. Drives are mounted outside the
airstream. Th
e sheaves shall be of a cast iron type. Standard
drive sheaves are [adjustable with a plus or minus 7%
adjustability on 10HP motors and smaller] [fi xed pitch type
on 15HP motors and larger]. Th
e service factor used for V-
belt drives shall be not less than 1.25. An adjustable motor
base shall provide variation in center distance and shall be
readily adjustable by means of screw adjustments. A locking
nut, or similar device, shall be provided to secure the base in
proper position.
C. Fan Bearings: Blower wheels shall be supported by
[two][three] [four] outboard bearings which shall be of a
self-aligning, ball bearing type and shall have an ABMA L10
rated life of 100,000 hours.
D. Motor: Motor shall be [ODP], [TEFC], [explosion proof],
[high effi ciency], 1800 RPM, [1 Ш][3 Ш], 60 Hz, wired for
the selected voltage. Motor horsepower shall be as indicated
on the schedule. All 3 Ø motors shall be controlled and
protected by an automatic starter with thermal overload
protection. Starter shall be interlocked to prevent burner
operation when overload relays are tripped. Motors are
mounted outside the airstream.
2.7 CONTROL SYSTEM
A. Factory Testing: Th e off /low-fi re/high-fi re operation of
the burner shall be controlled by means of a temperature
control.
B. Control Enclosure: A factory pre-wired control cabinet
shall be supplied with the burner. Cabinet is mounted on or
near burner. Cabinet to house the fl ame safeguard control,
programming purge timer, burner motor starter, fuses,
control switches and relays. Th
e unit shall be provided with
an integral weatherproof control panel with 115 volt control
transformer, fuses, terminal strip, and motor starter with
overload protection. Fan/blower motor(s) will be wired to
the motor starter(s).
C. Disconnect Switch (Optional): A unit disconnect switch
shall be provided [on the exterior of the unit for single point
wiring connection][loose].
D. Flame Relay: A manual restart of the burner shall be
necessary in the event of shutdown due to fl ame failure.
E. Safety Controls:
1. High Gas Pressure: Th e high gas pressure switch
shall turn the burner off when the gas pressure is above
its setpoint. Th
e maximum gas pressure shall be set at
1" above the maximum gas pressure at high fi re.
2. Low Gas Pressure: Th e low gas pressure switch shall
turn the burner off when the gas pressure is below its
setpoint. Th e minimum gas pressure shall be set at 7"
w.c..
3. High Temperature Limit Switch: A manual reset high
temperature switch shall turn the burner off when air
is discharged above its setpoint. Th
e high temperature
limit switch shall be factory set at 200° F.
F. Electronic Controls System:
1. Temperature Controller: Provide with either discharge
temperature or room temperature controller.
2. Remote Control Panel (One for Each Unit): Mount
unit operating switch and Remote Panel lights, as
follows:
• Including Summer/Off /Winter switch, Blower on/off
light, Burner on/off light, fl ame failure light
(standard) and room temperature thermostat
(optional).
• Night setback with Occupied/Unoccupied switch,
seven-day mechanical timeclock or seven-day
electronic timeclock (optional).
• Unit mounted on/off toggle switch (optional).
• Clogged Filter light (optional).
• Burner alarm horn (optional).
• Burner on/off outdoor air thermostat (optional).
• Fan on/off low-limit control with bypass timer
(optional).
2.8 AIR HANDLER OPTIONS AVAILABLE
(Select Applicable Options)
A. Roof Curb: [Burner/blower sections only] [full perimeter]
roof curb available in height of [16"] [24"]. Curbs shall be
manufactured of minimum 14 gauge galvanized steel with
all the hardware for bolt-together assembly. Curb is to be a
minimum of 16" high.
B. Inlet Hood: Hood shall be manufactured of a minimum of
16 gauge steel. A galvanized birdscreen is to be supplied.
Air velocities at wind resistant angled intake are not to
exceed velocities which would approach water carry-over.
C. Insulation: (Optional): Insulation shall be 1", 1.5 lb. per sq.
ft . rigid, rot-proof, non-combustible glass fi ber insulation.
Mount insulation in roof, sides, fl oors, interior partitions
and all service doors of [burner/blower section only] [entire
unit]. Insulation shall be matte-faced when in single wall
application.
D. Discharge Head: Th e manufacturer shall provide an
adjustable, double-defl ection discharge head for units with a
horizontal discharge. Units with a bottom discharge shall be
provided with an adjustable, four-way plenum.
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