Addison DCA Series User manual

INSTALLATION OPERATION and MAINTENANCE MANUAL
100% Outside Air Cooling/Dehumidifying Units
High Efficiency Packaged PCA/DCA Systems
CONTENTS PAGE
Safety Labeling and Signal Words......................2
General Description............................................3
Unit Location ......................................................3
Installation.................................................. 3, 4, 5
Sequences of Operation ................................ 5-10
Start-up Procedures..........................................10
Preparing Equipment for Operation.............10, 11
Service.........................................................11, 12
Typical Wiring Diagrams...............................13-16
Adjustable Belt Drive Blower............................17
General Service Guide ..................................18-20
Check, Test and Start Form ..............................21
WARNING: READ SAFE OPERATION RULES AND MANUAL CAREFULLY
APPLICATION
PCA Series endflow packaged and DCA Series Down
discharge air conditioners are designed to cool and
dehumidify 100% outside air for those applications
requiring make up air cooling. These units should not
be used as the primary source of cooling or heating
the conditioned space.
Safe Operation Rules
Please take a few minutes to read our instructions
before you install and use your air conditioner. This will
help you obtain the full value from your air conditioner.
It will also help you avoid any needless service costs
that result from causes we cannot control and cannot
cover in our warranty.
Follow these rules and the instructions carefully.
Failure to do so could cause a malfunction of the air
conditioner, resulting in injury, death and/or property
damage.
Check local codes and utility standards. The
installation must comply with their rules.
Always shut off electric power before making unit
connections or removing any panels.
During installation or servicing, be extremely careful to
avoid injury. Components may have sharp edges or
protrusions which can cut you. Tubing and
compressor(s) contain high pressure refrigerant—they
must not be exposed to high temperature or be
punctured.
Operational failure of this unit for any reason, including but not limited to mechanical or electrical failure of devices
internal or external to the unit, loss of fuel such as natural or LP gas, or interruption of electric power may result in
the introduction of large volumes of air into the conditioned space that could cause freeze or other damage to
property.
It is the responsibility of the installer and/or user of this unit to provide equipment such as a source of emergency
heat, alarm systems, or supervisory systems to warn of such failures.
Form #0527N-0831B(0609)
!
CAUTION

Insert for all ADDISON®product manuals
Instructions:
In accordance with California Proposition 65 requirements, place enclosed label(s) in a highly visible location on outside of
equipment to be repaired (i.e., near equipment’s serial plate). See label placement drawing in equipment’s Installation, Op-
eration and Service manual for label location (when available). Avoid placing label on areas with extreme heat, cold, corro-
sive chemicals or other elements. Extra labels are also included where repair of multiple units is involved. To order additional
labels, please call +1.407.292.4400.
To obtain a copy of the manual or for more information, visit the applicable website(s) below:
Incluya en todos los Manuales de productos de ADDISON®
Instrucciones:
De conformidad con los requerimientos de la Propuesta 65 de California, ubique la(s) etiqueta(s) adjunta(s) en un lugar bien
visible en el exterior del equipo a ser reparado (es decir, cerca de la placa serial). Ver dibujo de instalación de la etiqueta en
el Manual de Operaciones y Mantenimiento (si esta disponible). Evite colocar la etiqueta en áreas con calor, frío, productos
químicos corrosivos u otros elementos. Se incluyen etiquetas adicionales para el caso de reparación de varias unidades.
Para ordenar etiquetas adicionales, por favor llamar al +1.407.292.4400.
Para obtener una copia del manual o para obtener mas información visite los sitios Web correspondientes a continuación.
www.addison-hvac.com
Código de Instalación e Inspecciones Anuales: Todas las instalaciones y mantenimientos de productos
ADDISON
®
deben ser realizados sólo por personal cualificado en la instalación y mantenimiento de los equipos
vendidos y suministrados por Addison y/o por sus distribuidores y deben cumplir con todos los requisitos
dispuestos en los manuales de ADDISON
®
y con todos los estándares locales aplicables a la instalación,
mantenimiento, funcionamiento y etiquetado del equipo. Para conseguir un funcionamiento óptimo y seguro,
Addison recomienda que un técnico cualificado revise anualmente sus equipos y realice el mantenimiento
siempre que sea necesario, usando exclusivamente piezas de repuesto de ADDISON
®
.
Información adicional: A través de los distribuidores de Addison está disponible la información sobre
aplicaciones, guías detalladas sobre diseño de sistemas e instalación y funcionamiento de los productos. Por
favor contacte con nosotros si necesita más información o si requiere un manual de instalación,
funcionamiento y mantenimiento.
Este producto no es para uso residencial.
La intención de este documento es la de ayudar a los profesionales autorizados en el libre ejercicio de su
profesión.
Installation Code and Annual Inspections: All installation and service of ADDISON
®
equipment must be performed by a contractor qualified in the
installation and service of equipment sold and supplied by Addison and conform to all requirements set forth in the ADDISON
®
manuals and all applicable
governmental authorities pertaining to the installation, service, operation and labeling of the equipment. To help facilitate optimum performance and
safety, Addison recommends that a qualified contractor conduct, at a minimum, annual inspections of your ADDISON
®
equipment and perform service
where necessary, using only replacement parts sold and supplied by Addison.
Further Information: Applications, engineering and detailed guidance on systems design, installation and equipment performance is available through
ADDISON
®
representatives. Please contact us for any further information you may require, including the Installation, Operation and Service Manual.
This product is not for residential use.
This document is intended to assist licensed professionals in the exercise of their professional judgment.
www.addison-hvac.com Printed in U.S.A. P/N 91070020 Rev B 03/12
Page 1 of 1
© 2012 Addison All rights reserved. No part of this work covered by the copyrights herein may be reproduced or copied in any form or by any means –
graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems – without
written permission of Addison.
Addison
7050 Overland Road
Orlando, FL 32810 U.S.A.
Telephone: [phone]
Fax: [phone]
www.addison-hvac.com

2
SAFETY LABELING AND SIGNAL WORDS
Danger, Warning and Caution
The signal words DANGER, WARNING and
CAUTION are used to identify levels of hazard
seriousness. The signal word DANGER is only used
on product labels to signify an immediate hazard.
The signal words WARNING and CAUTION will be
used on product labels and throughout this manual
and other manuals that may apply to the product.
Signal Words
DANGER –Immediate hazards which WILL result in
severe personal injury or death.
WARNING –Hazards or unsafe practices which
COULD result in severe personal injury or death.
CAUTION –Hazards or unsafe practices which
COULD result in minor personal injury or product or
property damage.
Signal Words in Manuals
The signal word WARNING is used throughout this
manual in the following manner:
The signal word CAUTION is used throughout this
manual in the following manner:
CAUTION
Product Labeling
Signal words are used in combination with colors
and/or pictures on product labels. Following are
examples of product labels with explanations of the
colors used.
This unit contains chlorodifluoromethane (HCFC-22), a substance that harms public health and environment by
destroying ozone in the upper atmosphere.
Do not vent HCFC-22 to the atmosphere. The U.S. Clean Air Act requires the recovery of any residual
refrigerant.
Electric Shock Hazard.
Turn Off All Power
Before Servicing.
Fire Hazard.
Use copper wire only.
Failure to observe could
result in property dam
age,
bodily injury or death.
WARNING
!
Danger Label
White lettering on a black background except the word
DANGER which is white with a red background.
Warning Label
White lettering on a black background except the word
WARNING which is white with an orange background.
DANGER!
Cuts and Abrasion Hazard.
Wear gloves and handle
with care.
Failure to observe could
result in bodily injury.
CAUTION
!
Caution Label
White lettering on a black background except the word
CAUTION which is white with a yellow background.
WARNING
!
WARNING
!
This unit contains HFC -(R410A), an Azeotropic mixture of R-32 (Difluoromethane) and R-125 (Pentafluoroethane). DO NOT VENT
HFC-(R410A) to the atmosphere. The U.S. Clean Air Act requires the recovery of any residual refrigerant. Do not use R-22 service
equipment or components on R410A systems.

3
GENERAL DESCRIPTION
Model PCA and DCA.
These cooling only 100% outside-air units may be roof
mounted on a factory supplied roof curb, slab mounted,
or installed on post and rails. Air is drawn into the
outside air intake located on the end of the unit and
through metal mesh filters before entering the
evaporator coil.
Every unit is charged with refrigerant and run tested
before shipment.
Unpacking
When received, the unit should be checked for damage
that might have occurred in transit. If damage is found, it
should be noted on the carrier’s Freight Bill. Request for
inspection by carrier’s agent should be made in writing at
once.
Codes and Ordinances
Local authorities having jurisdiction should be consulted
before installations are made to verify local codes and
installation procedures.
All field wiring to the unit must be done in accordance
with these instructions, the National Electric Code
(ANSI/NFPA 70-1981) in the United States and all local
codes and ordinances.
Installation should be done by a qualified agency in
accordance with the instructions in this manual and in
compliance with all codes and requirements of
authorities having jurisdiction.
UNIT LOCATION
Unit Location
An intake louver protects the service end and clearance
at this point should be maintained. A 36" clearance must
be allowed for access to the compressor and electrical
panel. A 24" clearance must be maintained for the air
inlet to the condenser coil(s).
Do not locate the unit under an overhang that will short
circuit hot air to the coil intakes.
When installed at ground level, the unit should be
mounted on a level concrete slab which should extend at
least 2" beyond the unit on all sides. The top of the slab
should be 2" above the ground level. The depth of the
slab below the ground level and its structural design is
governed by the type of soil and climatic conditions. The
slab must not be in contact with any part of the building
wall or foundation. The space between the slab and
building wall prevents the possibility of transmitting
vibration to the building.
The dimensions of the slab or roof mount should be
checked and verified before the equipment arrives. Unit
supports, roof
opening, roof curb flashing, drain requirements, and
electric locations are important to a good installation.
When installing the equipment on top of a building, the
following should be considered:
Structural members supporting the unit must be
sufficiently strong for the weight of the unit and mounting
rails.
Locate the unit as near as possible to the center of the
area to be environmentally controlled. Sufficient
clearance must be available for service, edge of roof,
other units, or hazards.
The condenser air inlet and discharge air must be
unobstructed by overhang, walls, or other equipment.
Avoid locations next to exhaust fans or flues.
Select a location where external water drainage cannot
collect around the unit.
Locate the unit so roof runoff water does not pour
directly on the unit. Provide gutter or other shielding at
roof level.
Where snowfall is anticipated, mount the unit above the
maximum snow depth for the area.
INSTALLATION
The installation of packaged units consists of making
final connections between the unit and building
services such as electrical power supply, natural gas,
supply and return duct connections, and drain
connections.
The internal systems of the unit are completely factory
installed and tested prior to shipment and no additional
field labor is required.
Setting the Unit
UNIT LOCATION
CAUTION: Units may look identical but have
significant internal differences. Check specific unit
location carefully (referring to plans if necessary) prior
to setting unit.
CURB INSTALLATION
Proper installation requires that the roof mounting curb
be firmly and permanently attached to the roof
structure. Check for adequate fastening method prior
to setting rooftop unit on curb.
PROTRUSIONS
Inspect curb to insure that none of the utility services
(electric, gas, drain lines) routed through the curb
protrude above the curb. Duct connections will
normally be made after unit is set on curb. If duct is
prefabricated and installed within the curb prior to
setting unit, insure that ductwork does not protrude
above curb.
DO NOT ATTEMPT TO SET UNIT ON CURB IF
PROTRUSIONS EXIST.

4
INSTALLATION Continued
UNIT INSTALLATION
Lower unit carefully onto roof mounting curb or mounting
rails or ground level slab. While rigging unit, center of
gravity will cause condenser end to be lower than
supply/return air end. Bring condenser end of unit into
alignment with curb. With condenser end of unit resting
on curb member and using curb as fulcrum, lower front
end of unit until entire unit is seated on curb.
Rigging Removal
Remove spreader bars, lifting cables and other rigging
equipment.
CAUTION:Do not allow crane hooks and spreader bars
to rest on roof of unit.
Ductwork
Properly sized and installed ductwork is critical to
reliable performance of the unit and system. Unit
connection sizes are in the engineering specification
manual. All ductwork must be installed according to local
codes, practices and requirements.
Industry manuals should be used as a guide to sizing
and designing the duct system.
Ducts passing through unconditioned spaces must be
well insulated with vapor barrier to prevent
condensation.
Condensate Piping
A condensate trap must be provided by customer.
Drainage of condensate directly onto the roof is
acceptable if permitted by local codes. It is
recommended that a small drip pad of either stone,
mortar, wood or metal be provided to prevent any
possible damage to the roof. If condensate is to be
piped into the building drainage system, the drain line
must penetrate the roof external to the unit. Refer to
local codes for additional requirements.
Electrical
Wiring Connections
Power wiring should be connected to the main power
terminal block located within the unit main control
section. Power wiring connections on units with factory
disconnects should be made at the line side of the
disconnect switch.
Low voltage wiring connections are made to the remote
mounted controller or time clock.
DO NOT TAMPER WITH FACTORY WIRING
Contact your local representative or the factory if
assistance is required. The internal power and control
wiring of these units is factory installed and each unit is
thoroughly tested prior to shipment.
Independent Power Source
It is recommended that an independent 115 volt power
source be brought to the vicinity of the rooftop unit for
portable lights and tools used by the service mechanic.
Main Power Wiring
The units are factory wired for the voltage shown on the
nameplate.
Main power wiring should be sized for the minimum wire
ampacity shown on the nameplate.
An external weather-tight disconnect switch properly
sized for the unit total load is required for each unit.
Disconnect must be installed in accordance with Local
and/or National Electric Codes.
Power wiring may enter the Rooftop Unit through the
side on all models, or through the unit base and roof
curbs on models with the Power Through Curb option.
Install conduit connectors at the entrance locations.
External connectors must be weatherproof.
Grounding
All units must be properly grounded. The ground lug is
provided for this purpose. DO NOT use the ground lug
for connecting a neutral conductor. The unit must be
electrically grounded in accordance with local codes, or
in the absence of local codes, with the NEC ANSI/NFPA
70 1981.

5
INSTALLATION CONTINUED
Once it is established that supply voltage is within the
utilization range; check and calculate if an unbalanced
condition exists between phases. Calculate percent
voltage unbalance as follows:
Percent Maximum Voltage Deviation
Voltage = 100x From Average Voltage
Unbalance Average Voltage
FOR EXAMPLE -With voltage of 220, 215, and 210
(Measure L1-L2, L1-L3, L2-L3).
Average voltage = 645 ÷ 3 = 215
Maximum voltage deviation from
Average voltage = 220 -215 = 5
Percent 100 x 5 =500
Voltage Unbalance
215 215 =2.3%
Percent voltage unbalance must not exceed (2%)
two percent.
Contact power company if phase unbalance exceeds
2%.
A means of disconnecting power from the unit must be
placed adjacent to the unit in accordance with National
Electrical Code or local codes. Aluminum power wire is
not recommended.
LOW VOLTAGE CONTROL WIRING
Control System Wiring: For commercial equipment the
following table lists the minimum size of 24 volt class 2
wire to be used.
Ft. Run From Unit to
Wire Size System Switch or Longest Run
18 A W G Maximum Run 50 Feet
16 A W G Maximum Run 75 Feet
14 A W G Maximum Run 100/125 Feet
12 A W G Maximum Run 150/200 Feet
Note: Wiring –Consult the wiring diagram furnished with
the unit. These units are custom designed for each
application.
The wiring diagrams in this publication are furnished only
as a guide to the installing contractor. The unit wiring
diagram is located inside the control panel of each unit.
SEQUENCES OF OPERATION
Temperature Controls: The Ambient Compressor
Thermostat controls compressor on/off operation. The
use of space or duct mounted sensors to control the
compressor will produce unpredictable results. On
systems with optional Hot Gas Reheat a discharge air
thermostat is mounted in the air handler. A
temperature/humidity sensor located in the conditioned
space may be used in conjunction with the control for
Hot Gas Reheat. A remote system switch such as a time
clock or interlock may be used to energized the controls.
Mechanical Cooling
The evaporator blower starts when the system switch is
closed. When the outdoor temperature rises above the
set point of the adjustable outdoor thermostat, the
compressor is active until the thermostat is satisfied. The
leaving air temperature will be maintained by hot gas
bypass and/or unloading the compressor. This is
accomplished through suction-pressure sensing, thus
tracking the outside air temperature variations.
When the outdoor temperature falls below the set point
of the adjustable outdoor thermostat (normally 56°F), the
compressor is deactivated.
Condenser Head Pressure Control
VARISPEED fan motor and control is standard with
all reheat options because units operating in low ambient
temperature require a control system to maintain stable
head pressure. Head pressure control is accomplished
with one or two variable speed condenser fan drives. A
pressure sensing control modulates the condenser fan
speed as required to maintain head pressure between
320 psig and 430 psig.
The Varispeed fan motor has been designed and tested
to withstand the high temperatures incurred during
variable speed operation DO NOT SUBSTITUTE.
Single fan models are equipped with one variable speed
motor and control.
Dual fan models may be are equipped with one single
phase variable speed motor and one 3 phase motor.
Four fan models may be equipped with one variable
speed motor and three 3 phase motors.
This pressure sensing system consists of a variable
speed motor driven fan and a constant speed motor
driven fan. Both are controlled from refrigerant pressure
rather than ambient temperature, reflecting actual
operating conditions in the machine.
At low ambient, the variable speed fan operates,
increasing in speed until maximum RPM is achieved at
or around 45°F (±2) ambient. An adjustable pressure
switch operates the constant speed three-phase fan set
to energize the motor at 400 psig and de-energize at 295
psig. In the ambient temperature span of approximately
50°F to 53°F, the variable speed fan will ramp between
maximum and minimum speed while the constant speed
fan cycles. The start-stop cycle varies from 45 seconds
to 22 minutes during this period.
At 53°F (±2), both fans are operating, the variable speed at
minimum RPM and the constant speed at full RPM. As the
ambient continues to rise, the variable speed motor increases
to full speed and remains there.

6
SEQUENCES OF OPERATION CONTINUED
If the application calls for a closer setting between
maximum and minimum pressure settings on the
constant speed fan, for example 275 psig on, 240 psig
off, the effect will be to lengthen the temperature span
during which the cycling takes place, for example 50°F
to 57°F.
Optional Hot Gas Reheat
Factory installed hot gas reheat circuit includes outlet
regulator valve, check valves, hot gas solenoid operated
control valve, variable speed condenser head pressure
control, one stage sensor, and one row heat reclaim coil.
The coil is equal to the evaporator face area and
installed in the reheat position. The sensor is factory
mounted. Hot gas reheat may not be operated below
60°F. ambient temperature.
Optional Reheat Plus
To lower relative humidity (RH) in the supply air stream,
a one row subcooling coil, generally equal to the
evaporator face area may be specified. The refrigerant
liquid passes through the tube side, adding up to 40°F.
of subcooling. For every two degrees of subcooling, the
compressor capacity is increased one percent. This is
also reflected as an increase in efficiency. The resulting
heat is passed into the air stream as reheat, usually 8°F
to 10° F. at 200 cfm/ton, thus the lower discharge air
relative humidity.
Reheat Plus™ Subcooling Reheat System Protected by U.S. Patent No. 5651258

7
SEQUENCES OF OPERATION CONTINUED
Application
Addison’s patented Reheat Plus adds a subcooling
coil to the Addison Hot Gas Reheat System. Its use is
especially applicable to 100% Outdoor Air systems, or to
recirculated air systems having high fresh air
requirements of over 20-25%. The subcooling coil is
active under all conditions of operation when the
compressor is running, and typically provides 4°-6° of
additional reheat at 350-400 CFM/Ton and 8°-12° of
additional reheat at 200 CFM/Ton. The leaving air dew
point will be lower then without the subcooling coil, and
the total refrigeration capacity and efficiency (EER) will
be higher
Typically, each two degrees of subcooling will result in
increased evaporator capacity of ½%. Thus, a typical
35°-40° of subcooling will result in increased unit
capacity of approximately 10%, with a corresponding
EER increase of over 1.0 BTU/Watt.
The use of Reheat Plus™ often allows the designer to
specify a smaller compressor to do a given job, or he
can accept the added refrigeration capacity and drive the
leaving dew point lower. In either case, Reheat Plus™
will give the optimum in leaving air conditions for a given
unit size, and allow them to be controlled more precisely
than ever before, at lowest operating cost.
See the following for controls and further description of
Addison’s Hot Gas Reheat System.
REHEAT SYSTEMS
Application
Hot gas reheat is a method used to maintain a specific
humidity level within the conditioned space. By installing
a one row coil equal to the evaporator face area down
stream of the evaporator the return air is cooled,
dehumidified and then reheated. By reheating the supply
air stream the relative humidity is reduced.
On 100% outside air applications the hot gas reheat will
provide leaving air temperature control. If not otherwise
specified (see Controls), control of the hot gas reheat is
via a factory mounted leaving air thermostat. The unit
employs continuous blower operation and the
compressor operation is controlled by an ambient
temperature thermostat.

8
SEQUENCES OF OPERATION CONTINUED
Reheat Operation
The hot gas reheat option includes differential pressure
regulator, check valve, hot gas solenoid operated valve,
VARISPEED variable speed condenser head pressure
control, single stage thermostat (factory mounted) and a
one row heat reclaim coil.
The adjustable differential pressure regulator is factory
set based on the reheat coil capacity and may require
further field adjustment after testing.
The VARISPEED head pressure control permits
stable refrigeration pressures over a wide range of
evaporator and ambient temperatures.
Refrigerant Flow
The VARISPEED Fan Control System basically
controls the compressor discharge pressure. The speed
control module responds to discharge pressure; it
speeds the condenser fan up as pressure rises and
slows the fan down as pressure falls due to load
conditions or as outdoor ambient temperature falls.
The Differential Pressure Regulator (DPR) is used to
maintain a constant differential of approximately 10 psig
across the reheat coil to assure the desired hot gas flow
through the coil. The DPR is field adjustable to allow
more or less gas to flow through the coil, giving a higher
or lower reheat temperature rise.
The Reheat Solenoid Valve (RSV) is installed ahead of
the reheat coil, and opens when reheat is required (see
Controls Section below). The Reheat Check Valve
(RCV) acts to prevent any back flow of hot gas into the
reheat coil when the RSV is closed.
The Hot Gas Bypass Valve (HGBPV) is not directly
associated with the reheat circuit, but serves to limit the
evaporator pressure. By introducing hot discharge gas
into the cold expanding refrigerant entering the
evaporator, a false load is imposed, thus keeping the
compressor suction pressure from falling to dangerously
low levels, and preventing coil freeze-up. The HGBPV is
field adjustable to satisfy a broad range of application
conditions.
The Hot Gas Bypass Solenoid (HGBPS) opens
whenever the compressor starts, and closes when it
stops. The Liquid Line Solenoid (LLS) opens when the
unit starts. If the system has a pumpdown circuit (larger
units, reciprocating compressors), when there is no
longer a call for cooling, the LLS closes, the unit pumps
down, and the compressor is shut down by the low
pressure control. On a call for cooling the LLS opens,
and rising evaporator pressure allows the low pressure
control to start the compressor.
If the unit does not include a pump down circuit, the LLS
& HGBPS serve as antimigration valves to keep
refrigerant from collecting in the evaporator and the
compressor crankcase during the off cycle.
Controls
There are many ways to control hot gas reheat. You
should choose the means that best fits your specific
application:
Thermostat –Terminals may be furnished in the control
panel of outside air units to allow control of the reheat
from the conditioned space. The factory mounted leaving
air thermostat will serve as a high limit control to prevent
adding heat into the space
Humidistat –Terminals may be furnished in the control
panel to switch the compressor and the reheat coil on or
off providing optimal humidity control. On outside air
units the humidistat will control the reheat coil only.
DDC –Terminals may be furnished, or the factory may
wire Direct Digital Controls to control the unit depending
upon the algorithm of the control.
If additional space temperature control is required,
additional circuits (up to four) may be controlled by an
electronic reset or DDC controller with both room and
duct sensor input. On a drop in space temperature, the
controller would energize or de-energize the hot gas
solenoid(s) in sequence to raise or lower the leaving air
temperature.
Operating Pressures
The operating pressures of the system may vary
somewhat from conventional operating characteristics.
Please refer to the Cooling Performance table on page
17 for approximate operating pressures.

9
SEQUENCES OF OPERATION CONTINUED
Hot Gas Bypass
Hot gas bypass is a means of capacity control during
lower ambient temperature conditions.
The Hot Gas Bypass valve is an adjustable valve and
should be set to open when the refrigerant suction
pressure drops to 107 –112 psig. It varies unit capacity by
introducing discharge refrigerant into the evaporator
circuit where it creates a false evaporator load. The hot
gas is cooled prior to its return to the compressor as it
passes through the evaporator.
The Hot Gas Bypass Solenoid Valve is energized
through the thermostat and routs discharge gas to the
hot gas bypass valve. It is deenergized during the pump
down cycle.
Optional Motorized Outside Air Damper
Motorized dampers are energized to open when the
compressor or compressors are operating.
Optional Clogged Filter Indicator
Dirty or clogged filters are red flagged by an indicator
when the preset pressure differential across the filters is
reached. The indicator is factory installed and manual-
reset. It includes contacts for remote annunciation.
SureTrip™ Phase Monitor
Provides line voltage monitoring and momentary power
failure (brown out) protection. At power interruption,
thermostat control voltage is interrupted. This device is
auto-reset with 5 minute time delay when line power is
restored. This devise also provides phase reversal
protection; therefore if it is replaced, motor rotation
should be verified.
START-UP PROCEDURES
Electrical shock, fire and/or explosion hazard.
Use extreme care during all of the following
checks and procedures.
Make sure Electric Power is turned OFF as
instructed in appropriate steps.
Failure to follow this warning can result in
property damage, personal injury, and/or death.
Check the unit’s operation as outlined in the following
instructions.
Blower and Phasing Check
1. Shut electric power OFF at unit disconnect.
2. Check to see that clean, properly sized air filters are
installed.
3. Check to see that everything inside the unit is clear
and ready to operate safely. Ensure that there are no
objects in, on or around the motor, belt or blower
wheel.
4. Set thermostat Heat-Cool selector (or time clock/
interlock switch) to OFF.
5. Set thermostat fan switch to AUTO.
6. Turn electric power ON. Nothing should start running.
If any unusual arcing, odors or noises are
encountered, shut electric power OFF immediately
and check for wiring errors.
NOTE: The circulation blower motor and compressor(s)
are three phase and are factory synchronized for proper
rotation. Even if the circulation blower motor comes on
and air seems to be circulating, it is possible that the
blower motor rotation is incorrect due to improper
phasing. The scroll compressor(s) (if equipped) will run
backwards under this condition and be damaged. It is
therefore necessary to check for proper rotation.
CAUTION
Do NOT operate the unit with the compressor(s) running
until proper blower rotation has been confirmed by
running the following test.
7. Set system ON. The circulating air blower should
come ON.
8. Shut electric power OFF at unit disconnect and
visually observe the direction of the blower rotation as
it slows down. Do NOT put hands or any other object
in, on or around the belt, motor or blower wheel. If
blower wheel rotation is the same as the directional
arrow on the blower housing, proceed to the next
step.
Moving parts hazard.
Do NOT put hands or any other object in, on or
around the motor, belt or blower wheel. Ensure
that there are no objects in, on or around the
motor, belt or blower wheel before turning
electric power on.
Failure to follow this warning can result in
property damage, personal injury, and/or death.
WARNING
WARNING
!
!

10
START-UP PROCEDURES CONTINUED
CAUTION
If blower rotation is incorrect, shut electric power
OFF at unit disconnect and reverse any two supply
wires at field connections ONLY. Do NOT reverse
the blower and/or compressor leads or rewire any
internal wiring. After rewiring is done, repeat
blower rotation check to ensure that blower
rotation is now correct.
9. Turn electric power ON at unit disconnect.
Cooling Checks
The compressors have a five minute anti-cycle delay
that is activated whenever the compressors turn off. For
instance, if the unit is manually shut off when the
compressors are running and the unit is turned back on
two minutes later, it will be an additional three minutes
before the compressors will restart.
CAUTION
Do NOT operate the unit with the compressor(s) running
until proper blower rotation has been confirmed during
the Blower and Phasing Check in the previous section. If
the phasing is incorrect, the scroll compressor(s) (if
equipped) will run backwards and they will be damaged.
PREPARING EQUIPMENT FOR OPERATION
PRE-START CHECKLIST
Is the unit properly located and level with proper
clearance?
Is the ductwork correctly installed?
Is the condensate line properly sized, run, trapped,
pitched and primed?
Is the air filter of the correct size and number, clean and
in place?
Is the wiring properly sized and connected according to
the unit wiring diagram?
Are all wiring connections tight including those in the unit
and compressor electrical boxes?
Has the unit been properly grounded and fused with the
recommended fuse size? See wiring data.
Has the unit been leak tested?
Do the condenser fans and indoor blower turn free
without rubbing and are they tight on the shafts?
Have all of the setscrews been tightened on the blower
motor and fan?
Has the belt tension in the blower been checked and
pulley aligned?
Has all work been done in accordance with applicable
local and national codes?
Are all covers and access panels in place to prevent air
loss and safety hazards?
Has the voltage been checked?
Has the crankcase heater been energized for 8 hours?
Be sure the system switch is “OFF”.
START-UP AND REQUIRED FIELD ADJUSTMENTS
Do not attempt to start-up system below 50°F. ambient
temperature.
Be sure the crankcase heater has been energized for a
minimum of 8 hours.
Break the vacuum with liquid R10A. Add to the liquid line
at the condenser until pressures are equalized.
Turn system switch on and operate unit. Now add
refrigerant vapor in the suction side until the liquid sight
glass is clear of bubbles. It is recommended the system
be charged initially by clearing the sightglass. Do not
overcharge, verify subcooling.
On systems with optional hot gas reheat it may be
necessary to adjust the reheat thermostat to 50 degrees
F. This setting will de-energize the reheat circuit. If not
disconnect the reheat thermostat.
On semi-hermetic compressors the cylinder unloading
coil will also be energized. It is energized by the
unloader pressure switch (senses suction pressure). The
unloader pressure switch MUST be field adjusted. It
should be set to close (unload) at 64 PSIG and open at
78 PSIG. This will maintain a refrigerant temperature in
the evaporator of approximately 40 degrees F.
The hot gas bypass valve should be energized and this
should be the maximum charge required for these units.
Units with reheat will require additional charge for the
reheat circuit.
Adjusting the hot gas bypass valve. This bypass valve
Must be field adjusted. The valve must open at 112 PSIG.
It may be necessary to simulate a light load if the
outdoor temperature is above 70-75 degrees F. Reduce
the evaporator load (lower entering airflow) until the
suction pressure lowers to the point at which bypass is
desired (112 PSIG). If the hot gas bypass was de-
energized to stop hot gas flow, make sure it is now
energized. Turn the power assembly adjusting stem on
top of the regulator in a clockwise direction until bypass
occurs (you will hear the gas flowing or feel the hot gas
line, it will be warm when the unit starts to bypass).
Check or ensure suction pressure does not fall
below the predetermined set point (102 PSIG). A
clockwise turn of the adjusting stem will increase
the pressure setting; a counterclockwise turn will
decrease it. Adjustments should be made in small
increments, allowing the system to stabilize after
each turn. Vary the evaporator load to test at various
conditions to ensure the suction pressure does not
drop below the predetermined setpoint. Replace the
seal cap on the adjusting stem.

11
PREPARING EQUIPMENT FOR OPERATION CONTINUED
Check the airflow by checking the external static
pressure. Verify the airflow is within the ratings. Check
blower motor amperage. Make adjustments as needed
to ensure airflow is correct and to specifications. On
units without hot gas reheat, the low ambient head
pressure control should be factory set to cut-in at 450
PSIG and cutout at 400 PSIG. Check calibration of this
control. If trim adjustment is required maintain a wide
differential.
On systems with optional hot gas reheat, check the
reheat control valve. This valve is factory set at a
differential of 8-10 PSIG. This should be adequate for
most applications. However, if additional reheat capacity
is required, increase the differential pressure to a higher
value. To do this, attach discharge pressure gauges to
the Schrader connections upstream and downstream of
the valve. Remove the cap from the top of the valve and
turn the stem clockwise to increase the pressure
differential and counterclockwise to decrease the
differential. Verify the operation of the reheat system by
turning the reheat thermostat to a temperature 5-10
degrees F. above the leaving air temperature. The
reheat solenoid will be energized and will cycle as the
temperature changes. Set the reheat thermostat at the
desired leaving air temperature. Adjustment should also
include a calibration check of the head pressure control
for the other fan motor(s) .The recommended settings
are to cut in at 350 PSIG and cutout at 400 PSIG.
Disregard these steps if the unit is not equipped with hot
gas reheat. These units utilize an electronic (P-66)
variable speed head pressure control for one condenser
fan motor. It is factory set to maintain a minimum head
pressure of 330 PSIG. For more information on the
reheat control valve, See Supplemental Instructions for
Hot Gas Reheat. Readjust the reheat thermostat to 65-
70 degrees F. The hot gas reheat circuit should be
energized. Again clear the sight glass. This would be the
maximum charge required for this system. The final
adjustment of the refrigerant charge should be by
subcooling. The recommended subcooling at the
condensing unit should be around 15 degrees at 75
degrees F. and as low as 5 degrees at 105 degrees F.
Verify proper operation of the thermostatic expansion
valve by checking the superheat. The superheat should
be 18-20 degrees at the suction line in the condensing
section.
SERVICE
MAINTENANCE
Filters must be checked at least once each month on
commercial operations. It is not recommended that filters
be allowed to load entirely with dirt before replacement
since this practice will permit excess dirt to foul the
cooling coil and introduce service problems by reducing
air flow. Provisions have been made for ease in
changing these items.
Belts and Pulleys should be checked whenever filters
are changed. Make sure belts and setscrews are set
tight. Check for wear, cracking, alignment, tension and
motor amperage.
Condensate Drains should always be checked whenever
filters are changed to ensure the condensate is draining
properly.
Condensate Drain Pan should be cleaned and flushed
every six months.
Bearings require no maintenance since sealed ball
bearings are used in the blower motor and condenser
fan motors. Lubrication is thus provided for the life of the
bearing.
Finishing of the sheet metal parts are done by painting in
an Electrodeposition paint system for a dipped and
baked enamel finish. Appearance can be restored with
automotive wax.
Seacoast Construction. Units furnished with the
Seacoast Construction protection option or other
corrosion protection coating (Heresite®or
ADDIGUARD™ 3600); it is imperative to clean and
inspect the cabinet, coils and components on a
semiannual basis. Use a chemical cleaning agent to
neutralize the contaminant. Then rinse thoroughly. Fresh
water rinsing alone does not constitute cleaning.
Controls require no routine maintenance. The points on
the compressor contactors will become discolored
through usage, but it will not effect system operation, Do
not dress or file contact points. Should a surge of power
or unusual condition damage points, replace them with
identical items from the manufacturer.
PARTS SECURITY CHECK
Before leaving an installation or operating the unit,
determine whether any loose parts should be tightened.
Failure to do this may lead to noisy operation.
Check all setscrews on blowers and fan blades.
Adjust and tighten all thrust collars.
Adjust all belts and check drives.
Retighten all electric connections.
The Standard base pan of all Addison Products roof
mounted packaged heating and cooling products is
equipped with a series of “weep” holes on the bottom
edges.
These ¾” threaded fittings are provided to allow natural
drainage of any rain water that has entered the unit in
the event service panels are incorrectly or incompletely
installed or damaged has occurred to the unit’s roof.
These “weep” holes are also a convenient means of
evacuating water used to wash the interior of the unit or
evaporator and reheat coils.
The threaded fittings accommodate drain piping or
maintenance hoses used to conduct water from the
inside of the unit to a safe disposal.
Thermoguard Protection
Thermoguard

12
The “weep” holes are not condensate drains, and need
not be trapped. They may be plugged or left open for
automatic drainage.
SERVICE CONTINUED
PROCEDURE FOR COMPRESSOR REPLACEMENT
Isolate the compressor and remove the refrigerant from
system.
Remove the inoperative compressor.
Install a properly sized suction line filter-drier in the
compressor suction line and replace liquid line drier.
Examine expansion valves and solenoid valves to see if
cleaning or replacement is required.
Install the replacement compressor.
Evacuate the compressor and system to 500 microns.
Open the compressor service valves and charge the
system with R410A after compressor evacuation.
Operate the system. Check the pressure drop across the
suction and liquid drier after the first 1½ hours of
operation. Pressure drop across a liquid line drier should
not exceed 5 PSI and the suction line filter-drier should
not exceed 3 PSI.
After 8 to 24 hours, take an oil sample and test with an
acid test kit. If the oil dirty or acidic, change the suction
line and liquid line filter drier and recheck after 8 hours of
compressor operation.
After two weeks, recheck oil acidity to see if another
change of suction line and liquid line filter-drier is
necessary.
In some cases non-condensable gases are produced
during the burnout. Compare the equalized head
pressure with the pressure (equivalent) to the outdoor
temperature. If the pressures are different, then the
system should be purged.
System cleaning after compressor mechanical failures:
Mechanical compressor failures such as oil pump, valve
plates, etc. may not necessarily contaminate the system.
Check oil of defective compressor by means of an oil
acid kit and check compressor for shorts, grounds and
continuity-if all checks negative, then it is only
necessary to evacuate replacement or repaired
compressor and install a new liquid line drier. Make an
acid test after 8 hours of operation.
ORDERING PARTS
When reporting shortages or damaged parts, give the
complete unit model and serial number which is stamped
on the unit rating plate. These units are made special to
order and the following parts list should only be used as
a guide. Do not order parts from these lists.
Cooling Performance Data at 200 CFM Per Ton
Evaporator Inlet Air
°F Evaporator Inlet- Outlet Air Temp
Differential, DB°F
High Side Pressure
psig
Condenser
Inlet Air
Dry Bulb°F Dry
Bulb Wet Bulb Min. Max. Min. Max.
105 105 87
82
58
33
33
38
315
310
345
340
95 95 80
75
37
32
32
37
275
270
305
300
85 85 72
67
26
31
31
36
230
225
260
255
75 75 65*
60*
22
26
27
31
215
210
245
240
*Condenser fan at part load RPM, unit at partload operation
510
556
500
550
445
490
440
485
375
420
365
415
350
345
400
390

13
TYPICAL 208/230-1-60 WIRING DIAGRAM

14
TYPICAL 208/230-3-60 WIRING DIAGRAM

15
TYPICAL 460-3-60 WIRING DIAGRAM

16
TYPICAL 380/415-3-50 WIRING DIAGRAM

17
ADJUSTABLE BELT DRIVE BLOWER
Personal injury hazard.
Use extreme care during the following procedures
and obey Safety Information.
Failure to do so may result In personal Injury.
The following safety rules MUST always be followed
when working near belt drive.
Always Turn the Power Off
1. Turn the power to the unit OFF before you begin
working on it.
Always Wear Protective Clothing
2. NEVER wear loose or bulky clothes, such as
neckties, exposed shirttails, loose sleeves, or lab
coats around belt drives. Wear gloves while
inspecting sheaves to avoid nicks, burrs, or
sharply worn pulley edges.
The blower speed is changed by adjusting the
variable speed pulley mounted on the blower
motor.
If the blower speed needed is different than the
speed of the blower as shipped, follow the steps
below to change the blower speed. Before
changing the blower speed, read the above
safety rules first.
3. Turn electric power OFF.
4. Remove the side blower access panel.
Loosen the four motor mount bolts.
6. Turn the motor adjustment bolt counterclockwise
until the belt is slack enough to come off easily.
7. Remove the belt. Do NOT pry off belt.
8. Loosen set screw(s) on the outer half of the
adjustable pulley.
9. The unit has one of two different types of
adjustable pulleys.
10. Remove key if unit has a keyway type pulley.
11. To set the blower for a desired CFM (L/s), first
turn the outer half of the adjustable pulley
clockwise until it meets the inner half of the
pulley.
12. Turn the outer half of the adjustable pulley
counter clockwise the correct number of turns to
obtain the desired CFM (L/s).
NOTE: To increase the blower speed, turn the
outer half of the adjustable pulley clockwise. To
decrease the blower speed, turn the outer half of
the adjustable pulley counter clockwise.
13. Replace key if unit has keyway type pulley.
14. Tighten set screw(s).
15. Put on belt.
16. Turn motor adjustment bolt clockwise until the
belt has enough tension at the proper deflection.
Use one of the commercially available belt
tension gauges to set the correct tension at the
proper deflection.
17. Use a straight edge (angle iron, straight piece of
board or anything with a good straight surface or
edge) to check the alignment of the blower pulley
with blower motor pulley.
18. It may be necessary to back the tension off the
belt temporarily and tighten one of the motor
mount bolts before it is possible to adjust the
angle of the blower motor.
19. Tighten all four blower motor mount bolts

18

19