Specifications

GUIDE SPECIFICATIONS 7-46 kW DX units

type with complete overload protection on all three power lines, internal thermostats for winding protection, crankcase heater,

sight-glass, condensers with sub-cooling and 2-way water regulating valve for head pressure control. The circuits shall contain

high and low pressure safety switches. The high and low-pressure safety switches shall be installed with Shraeder type ﬁ ttings

with valve core.

The doors shall be painted to match or contrast with other room equipment.

Each system shall include a low proﬁ le, slow speed, direct drive propeller fan type air cooled ﬂ uid cooler. Air discharge shall

be vertical to prevent wind from blowing through the coil at low ambient temperatures. The ﬂ uid cooler shall be constructed of

aluminum and contain a 1/2” O.D. riﬂ ed copper tube coil with corrugated aluminum ﬁ ns for maximum heat transfer. The fan mo-

tors shall have cycling control provided on ﬂ uid coolers with multiple fan motors. The ﬂ uid cooler shall include surge tank and

ﬁ ll valve, pump contactor, and fan cycling controls with integral factory wired and tested control panel. The ﬂ uid cooler shall be

manufactured by the same manufacturer as the indoor unit.

1.04 DIRECT DRIVE PLENUM FAN SECTION

A. The supply air fan shall be single width, single inlet plenum fan with backward inclined aluminum blades. Fan wheel

shall be directly connected to its motor for greater efﬁ ciency. Fan/motor assembly shall be statically and dynamically balanced for

quiet, vibration-free operation and shall have a minimum L10 life of 60,000 hours. Fan shall be maintenance free throughout its

operating life.

B. The fan motor shall be electronically commutated (EC) synchronous DC motor and shall meet the NEMA Premium

standard. The EC motor shall have soft start capability and shall be controlled via the keypad on the unit mounted controller or by

a 4 to 20 mili-amp control signal sent directly to the analog input on the motor. The fan shall be mounted within the unit and fully

enclosed in an integral plenum to allow efﬁ cient operation on raised ﬂ oors with 12 or more inches of clearance under the ﬂ oor.

C. Belt drive fans with variable frequency drives are not considered equal or acceptable.

1.05 FILTER CHAMBER

The ﬁ lter chamber shall be an integral part of the system, designed within the frame and cabinet. The ﬁ lters shall be four inch

(4”) deep pleated design, rated not less than 30% efﬁ cient (based on ASHRAE Std. 52-76).

1.06 ELECTRIC REHEAT

The reheat shall be of the ﬁ nned enclosed, sheath type, fabricated of stainless steel core sheath with plated ﬁ ns to withstand moist

conditions. The reheat shall be installed on the air discharge side of the cooling coil. The total kW shall be ___ to operate on a

supply of ____ volts.

1.07 HUMIDIFIER

The unit shall be provided with steam generator type humidiﬁ er. The steam generating humidiﬁ er shall be of the self-contained

disposable cylinder type with electronic controls. The capacity shall be adjustable from 10 to 30 pounds per hour. Power con-

sumption at 10 pounds per hour shall be 3.4 kW or less. The humidiﬁ er shall discharge pure steam with no material dust carry-

over and have a self-regulating automatic ﬂ ush cycle. Cylinders shall be disposable not requiring cleaning or maintenance. The

humidiﬁ er ﬁ ll level, water conductivity and ﬂ ush rate shall automatically adapt, both in frequency and duration, to variations in

the incoming water.