036-21060-004-A-1102
Unitary Products Group
3
DESCRIPTION (Cont’d.)
A fixed outdoor air intake assembly is shipped in the return air
compartment of all units ordered without an economizer or
motorized outdoor air damper option. The assembly includes
a rain hood with a damper that can be set for 10, 15 or 25%
outdoor air. With bottom duct connections, the intake damper
assembly should be mounted over the opening in the return
air panel. With horizontal ductwork, it should be mounted on
the return air duct. All supply air blowers are equipped with a
belt drive that can be adjusted to meet the exact require-
ments of the job.
All compressors include internal pressure relief. Every refrig-
erant circuit includes an expansion valve, a liquid line filter-
drier, a discharge line high pressure switch and a suction line
with a freezestat and low pressure/loss of charge switch, to
protect all system components.
Compressors and electric heater elements carry an additional
4-year warranty. Aluminized steel tubular heat exchangers
carry an additional 9-year warranty.
•
Simplicity™ Controls
- Simplicity™ control boards
have standardized a number of features previously avail-
able only as options or by utilizing additional controls.
•
Low Ambient
- An integrated low-ambient control
allows all units to operate in the cooling mode down
to 0ºF outdoor ambient without additional assis-
tance. Optionally, the control board can be pro-
grammed to lockout the compressors when the
outdoor air temperature is low or when free cooling
is available.
•
Anti-Short Cycle Protection
- To aid compressor
life, an anti-short cycle delay is incorporated into the
standard controls. Compressor reliability is further
ensured by programmable minimum run times. For
testing, the anti short cycle delay can be temporarily
overridden with the push of a button.
•
Fan Delays
- Fan on and fan off delays are fully pro-
grammable. Furthermore, the heating and cooling
fan delay times are independent of one another. All
units are programmed with default values based
upon their configuration of cooling and heat.
•
Safety Monitoring
- The control board monitors the
high and low-pressure switches, the freezestats, the
gas valve, if applicable, and the temperature limit
switch on gas and electric heat units. The unit con-
trol board will alarm on ignition failures, compressor
lockouts and repeated limit switch trips.
•
Nuisance Trip Protection and Strikes
- To prevent
nuisance trouble calls, the control board uses a
“three times, you’re out” philosophy. The high and
low-pressure switches and the freezestats must trip
three times within two hours before the unit control
board will lock out the associated compressor.
•
On Board Diagnostics
- Each alarm will energize a
trouble light on the thermostat, if so equipped, and
flash an alarm code on the control board LED. Each
high and low-pressure switch alarm as well as each
freezestat alarm has its own flash code. The control
board saves the five most recent alarms in memory,
and these alarms can be reviewed at any time.
Alarms and programmed values are retained
through the loss of power.
All gas heat models are built with two heating sections for two
equal stages of capacity control. Each section includes a
durable heat exchanger with aluminized steel tubes, a redun-
dant gas valve, spark ignition, power venting, an ignition
module for 100% shut-off and all of the safety controls
required to meet the latest ANSI standards.
The gas supply piping can be routed into the heating com-
partment through a hole in the base pan of the unit or through
a knockout in the piping panel on the front of the unit.
All electric heat models are wired for a single power source
and include a bank of nickel chromium elements mounted at
the discharge of the supply air blower to provide a high veloc-
ity and uniform distribution of air across the heating elements.
Every element is fully protected against excessive current
and temperature by fuses and two thermal limit switches.
The power supply wiring can be routed into the control box
through a threaded pipe connection in the base pan of the
unit. It can also be routed knockout in the wiring panel on the
front of the unit.
All models are available with factory mounted BAS Control.
Options are Novar, Honeywell, Johnson, or CPC.
All internal factory wiring is color coded and numbered for
ease in servicing and troubleshooting.
FACTORY-INSTALLED OPTIONS
•
SINGLE INPUT ELECTRONIC ENTHALPY ECONO-
MIZERS
- Includes a slide-in / plug-in damper assembly
with fully modulating spring-return motor actuator capa-
ble of introducing up to 100% outdoor air with nominal
1% leakage type dampers.
The enthalpy system contains one sensor that monitors
the outdoor air and determines when the air is cool
enough and dry enough to provide free cooling.
