Accurex XRV Operator’s Manual
Document 475597
Model XRV
Packaged Rooftop Ventilator
Installation, Operation and Maintenance Manual
Please read and save these instructions for future reference. Read carefully before attempting to assemble, install,
operate or maintain the product described. Protect yourself and others by observing all safety information. Failure
to comply with instructions could result in personal injury and/or property damage!
General Safety Information
Only qualified personnel should install and maintain this
system. Personnel should have a clear understanding of
these instructions and should be aware of general safety
precautions. Improper installation can result in electric
shock, possible injury due to coming in contact with
moving parts, as well as other potential hazards. Other
considerations may be required if high winds or seismic
activity are present. If more information is needed,
contact a licensed professional engineer before moving
forward.
1. Follow all local electrical and safety codes, as well
as the National Electrical Code (NEC), the National
Fire Protection Agency (NFPA), where applicable.
Follow the Canadian Electrical Code (CEC) in
Canada.
2. All moving parts must be free to rotate without
striking or rubbing any stationary objects.
3. Unit must be securely and adequately grounded.
4. Do not spin wheel faster than maximum cataloged
fan RPM. Adjustments to fan speed significantly
affect motor load. If the fan RPM is changed, the
motor current should be checked to make sure it is
not exceeding the motor nameplate amps.
5. Verify that the power source is compatible with the
equipment.
6. Never open access doors to the unit while it is
running.
WARNING
The roof lining contains high voltage wiring. To
prevent electrocution, do not puncture the interior or
exterior panels of the roof.
DANGER
• Always disconnect power before working on or near
this equipment. Lock and tag the disconnect switch
or breaker to prevent accidental power up.
• If this unit is equipped with optional gas accessories,
turn off gas supply whenever power is disconnected.
CAUTION
This unit is equipped with a compressed refrigerant
system. If a leak in the system should occur,
immediately evacuate the area. An EPA Certified
Technician must be engaged to make repairs or
corrections. Refrigerant leaks may also cause bodily
harm.
CAUTION
When servicing the unit, the internal components may
be hot enough to cause pain or injury. Allow time for
cooling before servicing.
Packaged Rooftop Ventilator 1
Table of Contents
General Safety Information ......................1
Receiving, Handling, Storage ....................3
Product Overview .............................4
Subassemblies ...............................5
Installation ................................. 6-9
Recommended Electrical and
Gas Supply Entry Locations ....................10
Piping Installation ............................11
Electrical Information. . . . . . . . . . . . . . . . . . . . . . . . . . 12
Control Center Components ....................13
Component Operation. . . . . . . . . . . . . . . . . . . . . . . . . 14
Optional Component Operation .............. 14-16
Factory-Installed Refrigeration System
Components ........................... 17-19
Start-Up – Unit ........................... 20-24
Start-Up – Components .................... 25-26
Troubleshooting ........................... 27-32
Routine Maintenance .........................33
Maintenance Procedures ......................34
Reference
Venting Connection Locations ................35
Rated Airflow ..............................36
Maintenance Log .......................... 37-39
Our Commitment ...................... Backcover
Packaged Rooftop Ventilator2
Receiving
This product may have been subject to road salt during
transit. If so, immediately wash off all visible white
reside from all exterior surfaces. Upon receiving the
product, check to ensure all line items are accounted
for by referencing the delivery receipt or packing list.
Inspect each crate or carton for shipping damage before
accepting delivery. Alert the carrier if any damage is
detected, do not refuse shipment. The customer shall
make notation of damage (or shortage of items) on the
delivery receipt and all copies of the bill of lading which
should be countersigned by the delivering carrier. If
damaged, immediately contact your manufacturer’s
representative. Any physical damage to the unit after
acceptance is not the responsibility of the manufacturer.
Handling
Units are to be rigged and moved by the lifting brackets
provided. Location of brackets varies by model and size.
Handle in such a manner as to keep from scratching or
chipping the coating. Damaged finish may reduce ability
of unit to resist corrosion.
Unpacking
Verify that all required parts and the correct quantity
of each item have been received. If any items are
missing, report shortages to your local representative to
arrange for obtaining missing parts. Sometimes it is not
possible that all items for the unit be shipped together
due to availability of transportation and truck space.
Confirmation of shipment(s) must be limited to only
items on the bill of lading.
Storage
Units are protected against damage during shipment. If
the unit cannot be installed and operated immediately,
precautions need to be taken to prevent deterioration of
the unit during storage. The user assumes responsibility
of the unit and accessories while in storage. The
manufacturer will not be responsible for damage during
storage. These suggestions are provided solely as a
convenience to the user.
The ideal environment for the storage of units and
accessories is indoors, above grade, in a low humidity
atmosphere which is sealed to prevent the entry of
blowing dust, rain, or snow. Units designed for outdoor
applications may be stored outdoors. All accessories
must be stored indoors in a clean, dry atmosphere.
Indoor
Maintain temperatures evenly to prevent condensation.
Remove any accumulations of dirt, water, ice, or snow
and wipe dry before moving to indoor storage. To
avoid condensation, allow cold parts to reach room
temperature. Leave coverings loose to permit air
circulation and to allow for periodic inspection.
The unit should be stored at least 3½ in. (89 mm) off
the floor. Clearance should be provided to permit air
circulation and space for inspection.
Outdoor
The unit should be placed on a level surface to prevent
water from leaking into the unit. The unit should be
elevated so that it is above water and snow levels.
Ensure sufficient support to prevent unit from settling
into soft ground. Locate parts far enough apart to
permit air circulation, sunlight, and space for periodic
inspection. To minimize water accumulation, place all
unit parts on blocking supports so that rain water will
run off.
Do not cover parts with plastic film or tarps as these
cause condensation of moisture from the air passing
through heating and cooling cycles.
Inspection and Maintenance
While in storage, inspect units once per month. Keep a
record of inspection and maintenance performed.
If moisture or dirt accumulations are found on parts,
the source should be located and eliminated. At each
inspection, rotate the fan wheel by hand ten to fifteen
revolutions to distribute lubricant on motor. If paint
deterioration begins, consideration should be given to
touch-up or repainting. Units with special coatings may
require special techniques for touch-up or repair.
Machined parts coated with rust preventive should be
restored to good condition promptly if signs of rust
occur. Immediately remove the original rust preventive
coating with petroleum solvent and clean with lint-free
cloths. Polish any remaining rust from surface with
crocus cloth or fine emery paper and oil. Do not destroy
the continuity of the surfaces. Wipe thoroughly clean
with Tectyl® 506 (Ashland Inc.) or the equivalent. For
hard to reach internal surfaces or for occasional use,
consider using Tectyl® 511M Rust Preventive, WD-40®
or the equivalent.
Removing from Storage
As units are removed from storage to be installed
in their final location, they should be protected and
maintained in a similar fashion until the equipment goes
into operation.
Prior to installing the unit and system components,
inspect the unit assembly to make sure it is in working
order.
1. Check all fasteners, set screws on the fan, wheel,
bearings, drive, motor base, and accessories for
tightness.
2. Rotate the fan wheel(s) by hand and assure no parts
are rubbing.
Packaged Rooftop Ventilator 3
Product Overview
A horizontally configured High Percentage Outdoor
Air unit designed for installation either indoors or
outdoors. Each unit has multiple options for cooling
and/or heating. The unit is designed to replace air that
is exhausted from the building and also heat and cool,
as needed. The air volume produced by the unit is
constant, but can be optionally modulated to provide a
variable air volume (VAV) and recirculation is also offered
as an option.
Cooling
Units have the following cooling options available:
• Packaged DX
• Split DX
• Chilled water coil
• Air-source heat pump (ASHP)
Units with packaged DX are shipped fully charged with
refrigerant and are ready for operation upon arrival.
Heating
There are three different optional heat sources that can
be ordered for this unit:
• Indirect gas-fired furnace with one or two sets of
heat exchangers
• Electric heat with infinitely variable SCR control
• Hot water coil
• Air-source heat pump (ASHP)
Airflow Arrangement
The unit is capable of Constant Air Volume (CAV),
Variable Air Volume (VAV), 100% Outdoor Air and have
recirculating air options.
Safety Listing
Models are listed per ANSI/UL 1995, Heating and
Cooling Equipment and are ETL Certified.
Models and Capacities
The packaged rooftop ventilator is built on three
different platform sizes.
Model Cooling Capacity
XRV-25 5 to 15 tons
XRV-45 15 to 30 tons
XRV-70 25 to 45 tons
Packaged Rooftop Ventilator4
Subassemblies
Blower
Either one or two plenum-type fans. All units are
equipped with a plenum fan for Supply Air and a second
may be selected for Exhaust (Relief) Air.
Coils - Evaporator coil (optional)
Condenser coil (optional, packaged DX only)
Indoor coil (optional, air-source heat pump only)
Outdoor coil (optional, air-source heat pump only)
Water coil (optional)
Reheat coil (optional)
Compressors
Each unit having packaged DX will have either one or
two refrigerant compressors. Optionally, one of the
compressors may be a digital scroll type compressor.
Air-source heat pump units will have one inverter
scroll compressor and may contain a second staged
compressor.
Dampers
Motorized outdoor air damper, motorized recirculating
damper. Optional return air damper. Optional gravitytype exhaust damper.
Optional Barometric Relief Damper
Used during economizer mode of the unit when building
pressure increases, relief damper will open due to over
pressurization.
Electric Heater
An SCR controlled electric heater (not shown) is
available on the units. It has its own control panel and
may require a separate power supply. See unit-specific
wiring diagram.supply and has its own control panel.
See unit-specific wiring diagram.
Low Sound Condenser Fans
(optional)
Coils
(optional)
Supply Filters - All housings are available with a filter
bank depth of either 2 or 4-inch.
Indirect Gas-Fired Furnace - Furnace model PVG is
available on XRV-25 and XRV-45. Model XRV-70 uses
furnace model PVF 200-600 or model HMA 700-800.
Packaged DX System - Any unit may be ordered with a
packaged DX system. Housing size XRV-25 will include
either one or two compressors; XRV-45 will include two
compressors; housing size XRV-70 will include four
compressors; a condenser coil(s) and evaporator coil(s)
and all required components. Units that have packaged
DX are charged with R410A refrigerant. Do not use tools
or parts designed for other refrigerants on these units.
Air-Source Heat Pump - Units having an air-source heat
pump will include either one or two compressors, an
indoor and outdoor coil, and all required components.
Air-source heat pump units are charged with R410A
refrigerant. Do not use tools or parts designed for other
refrigerants on these units. Option not available on the
RV-110 and RVE-180.
Split DX
The unit may be ordered with a split DX system for
connection to a building cooling system.
Vestibule
Some units may be ordered with a factory-assembled
vestibule that is to be field-attached to the side of the
unit. See lifting instructions.
Outdoor Air Filters
Weatherhood Filters
(metal mesh)
Condenser Coils
(optional)
Packaged DX
Compressors
(optional)
Furnace Vest Plate
and
Furnace Control Center
(optional)
Main Control
Center
Plenum-Type
Supply Air Blower
Indirect Gas-Fired Furnace
(optional)
Outdoor Air
Damper
Recirculating
Damper
Plenum-Type
Exhaust Air Blower
Packaged Rooftop Ventilator 5
Installation
Typical Unit Weights and Dimensions
A
B
1
2
5
4
3
W
7
6
L
H
Component Access
1 Optional Inverter Compressor
2 Optional Compressor/Electrical
3 Optional Gas Furnace/Optional Electric Heater
4 Electrical
5 Supply Blower
6 Coil
7 Filters
(A)
Condensing
Section
(B)
Unit
Size
XRV-25 5-15 59.3 52.5 98.6 22.1 30.1 2,700
XRV-45 15-30 72.5 68.2 109 27.7 30.1 4,500
XRV-70 20-45 90 68 156 22/27^ 30 6,400
All dimensions are shown in inches. Weight is shown in pounds and includes largest supply and exhaust fans, PDX with reheat, largest indirect-gas
fired furnace, and all dampers. Actual weights will vary based on the unit configuration.
* Only available with powered exhaust ** Only available without barometric relief
+
Only available with barometric relief ^ Above 12,000 cfm
Nominal
tonnage
(tons)
Height
(H)
Width
(W)
Length
(L)
Intake
Nominal
weight
(lbs)
Outdoor
Intake
End
Supply
Discharge
Bottom
or
Side
Return
Intake
Bottom,
End**
or
Side*
Exhaust
Discharge
+
End
or
Side*
Service Clearances
CC End
ACS
Clearance
NA
Clearance
OA End
Unit Size ACS CC End OA End
XRV-25 40 42 42 24 18 30
XRV-45 36 58 42 24 18 30
ACS = Access
CC = Control Center
NA = Non-Access
OA = Outdoor Air Weatherhood
Packaged Rooftop Ventilator6
XRV-70 36 52 58 24 18 30
All dimensions are shown in inches.
*NA from Unit = no condensing section or piping vestibule
**NA from CS = condensing section
***NA from Vest = piping vestibule
*NA
from
Unit
**NA
from
CS
***NA
from
Vest
Installation
Additional Clearances for
Packaged DX Units
Packaged DX units require additional clearance
because they must have unrestricted air movement
around the condenser coil and condenser fans. Hot air
is being discharged from the condenser fans during
operation. Enough clearance must be provided to
avoid recirculation or coil starvation. When equipped
with condenser coils, the unit should never be placed
under an overhang or inside a building. A minimum of
48inches above the condenser fans is acceptable, but
unobstructed is strongly recommended.
Minimum 48 inches clearance
Condenser Fans
Minimum 18 inches
clearance
Condenser Coil
End view of rooftop unit with Packaged DX
Handling Concerns for
Packaged DX or Air-Source Heat Pump
Units with PDX or ASHP have a system that is
pressurized with refrigerant. If damage occurs, the
refrigerant could leak into the atmosphere or cause
bodily harm due to the extreme cold nature of
expanding refrigerant. Use protective equipment such
as gloves and safety glasses to minimize or prevent
injury in case of a system leak during installation.
Before Lifting
Before lifting, be sure that all shipping materials have
been removed from the unit.
Vestibule
Determine whether or not the unit has a vestibule that
must be field-attached to the side of the unit. Vestibules
are shipped assembled but detached from the unit.
They have lifting lugs on them so they can also be lifted
by crane, but the installed location of the unit may make
it preferable to install the vestibule on the unit prior to
lifting.
Field Power Access
Determine where high voltage and low voltage wiring is
to be brought into the cabinet. If wiring is to be brought
into the cabinet through the floor, see Alternate Supply
Entry Locations in this manual. If unit is to be installed
on a roof, cut access openings in the roof deck as
needed.
Additional Clearances for
Air Source Heat Pump
IMPORTANT
Air-source heat pumps are equipped with a defrost
cycle to remove ice from the outdoor coil. During
defrost cycles, melted water may drip from the bottom
of the refrigeration section under the outdoor coil.
In cold climates, proper drainage/heat tape must be
installed under the outdoor coil to prevent the buildup
of ice on the roof.
Air-source heat pump units require additional clearance
because they must have unrestricted air movement
around the outdoor coil and outdoor fans. Enough
clearance must be provided to avoid recirculation or
coil starvation. Air-source heat pump units should
never be placed under an overhang or inside a building.
A minimum of 48-inches above the outdoor fans is
acceptable, but unobstructed is strongly recommended.
Packaged Rooftop Ventilator 7
Installation
W
L
L
W
Lifting
1. Ensure that all shipping materials have been
removed from unit.
2. To assist in determining rigging requirements,
weights are provided in the Unit Weights &
Dimensions section of this manual.
3. Unit must be lifted by all lifting lugs provided at top
of unit.
4. Spreader bars must span the unit to prevent
damage to the cabinet by the lift cables.
5. Never rest the spreader bar on the unit.
WARNING
Spreader bars are required to prevent damage to the
cabinet, failure to do so can result in damage that is
the installer’s responsibility.
6. Always test-lift the unit to check for proper balance
and rigging before hoisting to desired location.
7. Never lift unit by weatherhood.
8. Never lift units in windy conditions.
9. Preparation of curb and roof openings should be
completed prior to lifting unit to the roof.
10. Check to be sure that gasketing (supplied by others)
has been applied to the top of the curb prior to
lifting the unit and setting on the curb.
11. Do not use fork lifts for handling unit.
Roof Curb Mounting
Roof curb details, including duct locations and
dimensions, are to be found in the roof curb assembly
instructions.
Rooftop units require curbs to be mounted first. The
duct connections must be located so they will be clear
of structural members of the building.
1. Factory-supplied roof curbs. Roof curbs are model
GKD which are shipped in a knockdown kit (includes
duct adapters) and require field assembly (by others).
Assembly instructions are included with the curb kit.
2. Install curb. Locate curb over roof opening and
fasten in place. Check that the diagonal dimensions are
within ± 1/8inch of each other and adjust as necessary.
For proper coil drainage and unit operation, it is
important that the installation be level. Shim the curb as
required to level. Install gasketing on top surface of curb
(provided by others).
3. Install ductwork. Installation of all ducts should
be done in accordance with SMACNA and AMCA
guidelines. Duct adapters are provided to support ducts
prior to setting the unit.
4. Set the unit. Lift unit to a point directly above the
curb and duct openings. Guide unit while lowering to
align with duct openings. Roof curbs fit inside the unit
base. Make sure the unit is properly seated on the curb
and level.
5. Fasten the unit, Fasten the unit to the curb/
equipment support(s) using appropriate methods. The
installer is responsible for determining appropriate
support and fastening methods to ensure compliance
with all applicable codes.
6. Install vestibule. If unit was ordered with a vestibule
and it has not yet been attached to the unit, caulk and
attach the vestibule at this time.
W
Packaged Rooftop Ventilator8
Typical Unit with Condensing Section and
Factory-Supplied Curb Kit
L
Installation
L
W
Optional Piping Vestibule
If the unit was ordered with the vestibule, the NA (NonAccess side) clearance dimension must be measured
from the vestibule.
L
W
Typical Unit with Piping Vestibule and
Factory-Supplied Curb Kit
Rail Mounting and Layout
• The units may be installed on rails provided and
installed by others. Ensure that rails are designed to
handle the weight of the unit and provide proper load
distribution on building supports.
• Make sure that rail positioning does not interfere with
the openings on the unit.
• Rails should run the width of the unit and extend
beyond the unit a minimum of 12 inches on each side.
• Set unit on rails.
Ductwork Configurations
NOTE
Downblast Discharge Ductwork - whenever
downblast discharge is used, the ductwork directly
beneath the unit must be connected with either a “T”
or an “L” configuration and the area directly beneath
the heat source must not have any openings such
as louvers or grates.
Typical Unit Installed on Rails Supplied by Others
No louvers or grates
Packaged Rooftop Ventilator 9
Recommended Electrical and Gas Supply Entry Locations
Manufacturer recommends that electrical service and
gas supply be brought into the cabinet through the
end wall, as shown below. There are three penetrations
into the cabinet that are required; one for high voltage
supply wiring, one for low voltage control wiring and one
for either gas supply or high voltage supply wiring for an
electric heater.
Optional Unit
Disconnect
Indirect
Gas
Supply
Location
Field Wiring
Recommended Gas and Electric Supply Entry Locations
Alternate Supply Entry Locations
Each installation is unique and as a result, alternate
entry locations may be field-located. Before using any
alternate entry location, verify the suitability of the
location and ensure the use of an alternate location
does not interfere with unit wiring, components or
functionality.
WARNING
Never drill holes in the roof of the unit! There is high
voltage wiring located between the inner and outer
roof panels. Damage to the wiring could cause severe
bodily harm or death.
Optional Gas Piping
Units with indirect gas-fired furnaces require fieldsupplied and installed gas supply piping.
Housing
Size
Total Heating
Capacity
(Input in MBH)
Gas
Connection
Size
Max Gas
Pressure
100
150
XRV-25
200
¾” NPT 14 in. wg.
250
300
300
XRV-45
¾” NPT 14 in. wg.400
500
200
250
300
350
XRV-70
400
¾” NPT 14 in. wg.
500
600
700
800
Gas Connections
If this unit is equipped with an indirect gas-fired furnace,
connection to an appropriate gas supply line will be
required. For complete information on installation
procedures for the optional gas furnace, refer the
PVF/PVG Indirect Gas-Fired Heat Module Installation,
Operation, and Maintenance Manual.
Ground
Joint
Gas Cock
From Gas Supply
Bleeder Valve or
1/8 in Plugged Tap
Typical Gas Supply Piping Connection
Packaged Rooftop Ventilator10
Union
8 in. Trap
Gas to
Controls
Piping Installation
Optional Coil Piping
Factory-installed cooling and heating components are
mounted in the coil section of the unit. The coil section
is downstream of the energy wheel on the supply air
side of the unit. Note the coil connection locations on
the picture. Coil connections are located external to the
unit.
Note: DX coil liquid connection is internal to units.
Water Coils
1. Piping should be in accordance with accepted
industry standards. Pipework should be supported
independently of the coils. When installing couplings,
do not apply undue stress to the connection
extending through the unit. Use a backup pipe
wrench to avoid breaking the weld between coil
connection and header.
2. Connect the water supply to the bottom connection
on the air leaving side and the water return to the
top connection on the air entering side. Connecting
the supply and/or return in any other manner will
result in very poor performance. Be sure to replace
factory-installed grommets around coil connections
if removed for piping. Failure to replace grommets
will result in water leakage into the unit and altered
performance.
3. Water coils are not normally recommended for
use with entering air temperatures below 40°F. No
control system can be depended on to be 100% safe
against freeze-up with water coils. Glycol solutions
or brines are the only safe media for operation of
water coils with low entering air conditions. If glycol
or brine solutions are not used, coils must be drained
when freezing conditions are expected. If required,
vent and drain connections must be fieldpiped, external to the unit.
4. Pipe sizes for the system must be selected on
the basis of the head (pressure) available from the
circulation pump. The velocity should not exceed
6 feet per second and the friction loss should be
approximately 3 feet of water column per 100 feet
of pipe.
5. For chilled water coils, the condensate drain
pipe should be sized adequately to ensure the
condensate drains properly. Refer to Drain Trap
section.
Direct Expansion (DX) Coils (Split DX)
1. Piping should be in accordance with accepted
industry standards. Pipework should be supported
independently of the coils. Undue stress should not
be applied at the connection to coil headers.
2. The condensate drain pipe should be sized
adequately to ensure the condensate drains properly.
Refer to Condensate Drain Trap section.
3. When connecting suction and liquid connections
make sure the coil is free from all foreign material.
Make sure all joints are tight and free of leakage. Be
sure to replace factory-installed grommets around
coil connections if removed for piping.
4. Manufacturer does not supply compressor,
condensing units, or thermal expansion valve (TXV)
with standard models. For further instruction on
DX coil installation and operation contact your
compressor and/or condenser manufacturer.
Condensate Drain Trap
This unit is equipped with a stainless steel condensate
pan with a stainless steel connection. It is important
that the drain connection be fitted with a P trap to
ensure proper drainage of condensate while maintaining
internal static pressures and to prevent migration of
sewer gas back into the unit.
A P trap assembly (kit) is supplied with each unit and is
to be assembled and installed
as local conditions require and
according to the assembly
instructions provided with
the P trap. If local and area
codes permit, the condensate
may be drained back onto the
roof, but a drip pad should be
provided beneath the outlet.
If local and area codes require a permanent drain line,
it should be fabricated and installed in accordance with
Best Practices and all codes.
In some climates, it will be necessary to provide freeze
protection for the P trap and drain line. The P trap
should be kept filled with water or glycol solution at all
times and it should be protected from freezing to protect
the P trap from damage. If severe weather conditions
occur, it may be necessary to fabricate a Ptrap and
drain line of metal and install a heat tape to prevent
freezing.
Condensate Overflow Switch
This unit is equipped with an optional factory-mounted
condensate overflow switch. In the event that a high
level of condensate is detected, a dry contact will be
powered (24 VAC). This dry contact can be used for
field monitoring of condensate levels. All monitoring and
control shall be provided by others.
Packaged Rooftop Ventilator 11
Electrical Information
WARNING
The roof lining contains high voltage wiring. To prevent
electrocution, do not puncture the interior or exterior
panels of the roof.
WARNING
To prevent injury or death due to electrocution or
contact with moving parts, lock disconnect switch
open.
For units with a gas furnace, if you turn off the power
supply, turn off the gas.
IMPORTANT
Before connecting power to the unit, read and
understand the following instructions and wiring
diagrams. Complete wiring diagrams are attached on
the inside of the control center door(s).
IMPORTANT
All wiring should be done in accordance with the latest
edition of the National Electric Code ANSI/NFPA70
and any local codes that may apply. In Canada, wiring
should be done in accordance with the Canadian
Electrical Code.
IMPORTANT
The equipment must be properly grounded and
bonded. Any wiring running through the unit in the
airstream must be protected by metal conduit, metal
clad cable or raceways.
CAUTION
If replacement wire is required, it must have a
temperature rating of at least 105ºC, except for an
energy cut-off or sensor lead wire which must be rated
to 150ºC.
DANGER
High voltage electrical input is needed for this
equipment. This work should be performed by a
qualified electrician.
CAUTION
Any wiring deviations may result in personal injury or
property damage. Manufacturer is not responsible
for any damage to, or failure of the unit caused by
incorrect final wiring.
Determine the Size of the Main Power
Lines
The unit’s nameplate states the voltage and the unit’s
MCA. The main power lines to the unit should be sized
accordingly. The nameplate is located on the outside of
the unit on the control panel side.
Determine the Size of Electric Heater
Wiring
An optional electric heater may require a separate
power supply. The power connection should be made
to the factory-provided electric heater disconnect and
must be compatible with the ratings on the nameplate,
supply power voltage, phase and amperage. Consult
ANSI/NFPA 70 and CSA C22.1 for proper conductor
sizing.
Provide the Opening(s) for the Electrical
Connections
Electrical openings vary by unit size and arrangement
and are field-supplied.
Connect the Power Supplies
Connect the main power lines and electric heater power
lines to the disconnect switches or terminal blocks
and main grounding lug(s). Torque field connections to
manufacturer’s recommendations.
Wire the Optional Convenience Outlet
The convenience outlet requires a separate 115V power
supply circuit. The circuit must include short circuit
protection which may need to be supplied by others.
Connect Field-Wired Low Voltage
Components
Most factory-supplied electrical components are
prewired. To determine what electrical accessories
require additional field-wiring, refer to the unit-specific
wiring diagram located on the inside of the control
center access door.
The low voltage control circuit is 24 VAC and control
wiring should not exceed 0.75 ohms.
Control wires should not be run inside the same conduit
as that carrying the supply power. Make sure that
field-supplied conduit does not interfere with access
panel operation. All low voltage wiring should be run in
conduit wherever it may be exposed to the weather.
If wire resistance exceeds 0.75 ohms, an industrialstyle, plug-in relay should be added to the unit control
center and wired in place of the remote switch (typically
between terminal blocks R and G on the terminal strip.
The relay must be rated for at least 5 amps and have a
24 VAC coil. Failure to comply with these guidelines may
cause motor starters to “chatter” or not pull in which
can cause contactor failures and/or motor failures.
Field-Provided Disconnect
If field-installing an additional disconnect switch, it
is recommended that there is at least four feet of
service room between the switch and system access
panels. When providing or replacing fuses in a fusible
disconnect, use dual element time delay fuses and size
according to the rating plate.
Packaged Rooftop Ventilator12
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