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GUIDE SPECIFICATIONS — 524A (cont)
5. Electric Heaters:
Heaters for nominal 240, 480, or 575-volt, 3-phase,
60 Hz power supply shall be factory-supplied for field
installation as shown on the equipment drawings.
Electric heat assembly shall be ETL and ETL, Can-
ada, agency approved, and shall have single-point
power wiring. Heater assembly shall include contac-
tors with 24-v coils, power wiring, 24-v control wiring
terminal blocks, and a hinged access panel. Electric
heaters shall not be used with air discharge plenum.
6. Air Discharge Plenum:
Plenum shall be factory supplied to provide free-blow
air distribution for vertical floor-mounted units. A
grille with moveable vanes for horizontal or vertical
airflow adjustment shall be included. Plenum shall
be field-assembled and field-installed on the unit’s
fan deck for blow-thru air distribution. Plenum shall
notbeusedwithelectricheaters.
7. Return-Air Grille:
Grille shall be factory supplied for field installation on
the unit’s return air opening.
8. Unit Subbase:
Subbase assembly shall be factory supplied for field
installation. Subbase shall elevate floor-mounted
vertical units to provide access for correct conden-
sate drain connection.
9. Economizer:
Economizer for ventilation or “free” cooling shall be
factory provided for field installation on either return
air opening of air handler. For free cooling applica-
tions, economizer shall be compatible with separate
thermostat; economizer dampers shall open when
outdoor air enthalpy is suitable for free cooling.
Economizer shall include enthalpy control and
damper actuator. Economizer shall be compatible
with accessory CO
2
sensor. Economizer damper
shall open when indoor CO
2
level rises above prede-
termined set point.
A 2 to 10 vdc actuator adapter must be field-supplied
and installed on economizer for demand control ven-
tilation using the CO
2
sensor accessory.
10. Thermostat Controls:
a. Commercial Electronic Thermostat with 7-day
timeclock, auto-changeover, multi-stage capabil-
ity, and large LCD temperature display.
b. Commercial Electronic Non-programmable Ther-
mostat with auto-changeover, multi-stage capac-
ity, and large LCD display.
11. Overhead Suspension Package:
Package shall include necessary brackets to support
units in a horizontal ceiling installation.
12. Condensate Drain Trap:
Trap shall have transparent, serviceable design for
easy cleaning. Kit shall include overflow shutoff
switchandwiringharnessforconnectiontoanalarm
if desired.
13. UV-C Germicidal Lamps:
UV-C emitters and fixtures shall be specifically
designed for use inside an HVAC system. An ASME
nozzled test apparatus using a 45 F airstream mov-
ing at not less than 400 fpm shall measure individual
lamp output. Lamp output at 253.7 nm shall not be
less than 10µW/cm
2
per inch of arc length measured
at a distance of one meter.
a. UV-C power supplies shall be high efficiency,
electric type which are matched to the emitters
and are capable of producing the specified output
intensity with an input power no more than
80 watts.
b. Emitters and fixtures shall be installed in sufficient
quantity and arranged so as to provide an equal
distribution of UV-C energy on the coil and drain
fan.
c. The minimum UV-C energy striking the leading
edge of the coil fins shall be not less than
820 µW/cm
2
at the closest point and through
placement, not less than 60% of that value at the
farthest point. Equal amounts are to strike the
drain pan, either directly or indirectly through
reflection.
d. Emitters and fixtures shall be installed at right
angles to the conforming lines of the coil fins,
such that through incident angle reflection, UV-C
energy strikes all target surfaces of the coil, drain
pan, and the available line of sight airstream.
14. CO
2
Sensor:
The field-installed CO
2
ventilation sensor measures
the amount of ventilation needed by the space and a
proportional integral derivative loop (PID) calculation
makes adjustments to the economizer minimum
position during occupied operation. The indoor CO
2
will be compared to an outdoor CO
2
reference before
making adjustments to the economizer minimum
position.
50TFQ004-012
524A072-300