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Direct Expansion Coil
Modules
Installation, Operation, and Maintenance Manual
Save these instructions
RECEIVING AND INSPECTION
WARNING!!
Direct Expansion Coil Module
Upon receiving unit, check for any interior and exterior damage, and if found, report it
immediately to the carrier. Also check that all accessory items are accounted for and are
damage free.
Installation of this module should only be performed by a qualified professional who has read
and understands these instructions and is familiar with proper safety precautions. Improper
installation poses serious risk of injury due to electric shock, and other potential hazards.
Read this manual thoroughly before installing or servicing this equipment. ALWAYS
disconnect power prior to working on module.
Direct Expansion Coil
. This document is the property of the owner of this equipment and is
required for future maintenance. Leave this document with the owner when installation or
service is complete.
A0011048
April 2013 Rev. 12
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TABLE OF CONTENTS
WARRANTY .................................................................................................................................................. 4
INSTALLATION ............................................................................................................................................. 5
Mechanical ................................................................................................................................................ 5
Site Preparation .................................................................................................................................... 5
Assembly .............................................................................................................................................. 5
Plumbing Connections ......................................................................................................................... 6
Typical Cooling Coil Drain Trap ............................................................................................................ 6
Compressor Installation and Connection ............................................................................................. 6
Optional Moisture Eliminator Panel .................................................................................................... 10
Roof Mount Installation with Blower Only Unit ................................................................................... 10
Indoor Installation with Direct Fired Unit............................................................................................. 10
Electrical ................................................................................................................................................. 11
Copper Wire Ampacity ....................................................................................................................... 11
Dry Contacts for Condensing Unit. ..................................................................................................... 11
Located in Pre-wire or Heated Make-up-air unit. ............................................................................... 11
Terminals on Condensing Unit ........................................................................................................... 11
OPERATION ............................................................................................................................................... 12
Start Up ................................................................................................................................................... 12
Special Tools Required ...................................................................................................................... 12
Start Up Procedure ............................................................................................................................. 12
Component Description .......................................................................................................................... 13
Typical Installation of an AC system .................................................................................................. 13
Troubleshooting ...................................................................................................................................... 14
Troubleshooting Chart ........................................................................................................................ 14
MAINTENANCE .......................................................................................................................................... 15
General Maintenance ............................................................................................................................. 15
Every 6 months ....................................................................................................................................... 15
Yearly ...................................................................................................................................................... 15
Start-Up and Maintenance Documentation .............................................................................................. 2
Job Information ..................................................................................................................................... 2
DX coil Information ............................................................................................................................... 2
Maintenance Record ............................................................................................................................ 2
Factory Service Department ................................................................................................................. 2
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WARRANTY
This equipment is warranted to be free from defects in materials and workmanship, under normal use and
service, for a period of 12 months from date of shipment. This warranty shall not apply if:
1. The equipment is not installed by a qualified installer per the MANUFACTURER’S installation
instructions shipped with the product,
2. The equipment is not installed in accordance with federal, state and local codes and regulations,
3. The equipment is misused or neglected,
4. The equipment is not operated within its published capacity,
5. The invoice is not paid within the terms of the sales agreement.
The MANUFACTURER shall not be liable for incidental and consequential losses and damages
potentially attributable to malfunctioning equipment. Should any part of the equipment prove to be
defective in material or workmanship within the 12-month warranty period, upon examination by the
MANUFACTURER, such part will be repaired or replaced by MANUFACTURER at no charge. The
BUYER shall pay all labor costs incurred in connection with such repair or replacement. Equipment shall
not be returned without MANUFACTURER’S prior authorization and all returned equipment shall be
shipped by the BUYER, freight prepaid to a destination determined by the MANUFACTURER.
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INSTALLATION
Sloped
DX
Air
It is imperative that this unit is installed and operated with the designed airflow and electrical supply in
accordance with this manual. If there are any questions about any items, please call the service
department at 1-866-784-6900 for warranty and technical support issues.
Mechanical
WARNING: DO NOT RAISE VENTILATOR BY THE INTAKE HOOD, FILTER
TRACKS, OR PIPING – USE LIFTING LUGS PROVIDED OR A SLING
Site Preparation
1. Provide clearance around installation site to safely rig and lift equipment into its final position.
Supports must adequately support equipment. Refer to manufacturer’s estimated weights.
2. Compressor Unit must be within 75 Ft of air handler unit.
3. Compressor Unit must not be near intake of air handler unit.
4. Consider general service and installation space when locating unit.
Assembly
There are several items shipped loose with the DX coil modules. These items include sheet metal
screws, nuts and bolts, and foam gaskets. It is important to know where the coil is to be installed. For
direct fired heaters and electric coil modules, the DX coil module mounts to the end discharge side of the
air handling unit. This keeps any refrigerant leaking from burning, avoiding the creation of toxic gasses.
Place caulk on the outside of any external screws used to prevent water leaks.
Upon unit arrival, follow the following procedure to assemble the DX coil.
For use with a direct fired or electric heater:
1. Attach the DX coil module to the discharge side of the air handler using the nuts, bolts and angle
bracket washers included. Apply the foam gasket to the air handler to ensure that there is a liquid
tight seal formed between the DX coil module and the air handling unit.
2. Attach the down discharge plenum to the end of the DX coil module using the supplied foam
gasket, nuts and bolts. Or, attach ductwork directly to the end of the unit using sheet metal
screws following SMACNA guidelines.
For use without a direct fired
or electric heater:
1. Attach the DX coil
module to the intake
side of the air handler
using the nuts, bolts and
Handler
Coil
Module
Intake Hood
angle washers included.
Apply the foam gasket to
the air handler to ensure
that there is a liquid tight
seal formed between the
DX coil module and the
air handling unit.
Curb Rail
2. Complete installation of
ductwork per SMACNA
standard installation.
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The airflow distribution screen is located on the incoming air side of the coil. This screen evens out the
airflow across the coil and allows for greater cooling efficacy. Removal of this screen may cause the coil
to freeze or more serious damage.
Plumbing Connections
There is one field plumbing connection required for proper DX coil operation. This is the drain pan
located under the DX coil. Depending on the size of the unit, the
coil can generate 5 gallons of water per hour. It is imperative that
the plumbing be sized accordingly. Also, it’s recommended that all
plumbing connections be sealed with Teflon tape or pipe dope.
Only 1” diameter PVC Pipe and low profile couplings should be
used. Additionally, the top horizontal length on the P-Trap should
be a minimum of 12”. No unions should be used. Add a clean out
as shown in the picture below.
The P-Trap drain should be attached to the end of the drain pipe on
the side of the unit. The trap is important for two reasons. First, it
can be piped to drain in the most convenient area. Second, it
keeps air from being drawn through the drain hole in the side of the
pan, impeding drainage.
Module
DXM1-1 1.625/1.125 3
DXM1-2 1.625/1.125 5
DXM1-3 1.625/0.875 10
DXM1-4 1.625/0.875 12.5
DXM2-1 1.625/0.875 5
DXM2-2 1.625/0.875 10
DXM2-3 1.625/0.875 15
DXM2-4 1.625/0.875 20
DXM3-1 1.625/0.875 10
DXM3-2 1.625/0.875 15
DXM3-3 1.625/0.875 20
DXM3-4 1.625/1.125 25
DXM4-1 1.625/0.875 20
DXM4-2 1.625/0.875 25
DXM4-3 1.625/1.125 30
DXM4-4 2.125/1.125 40
DXM5-1 2.125/1.375 30
DXM5-2 2.125/1.375 40
DXM5-3 2.125/1.375 50
All Coils are 2 circuit coils, except for
Connection size
(suction/liquid)
DXM1-1 and DXM1-2.
Tonnage
Typical Cooling Coil Drain Trap
Compressor Installation and Connection
There are several connections that need to be completed before the unit will function. Depending on the
module you have selected, you may have only one suction line and one liquid line to connect. Otherwise,
there are two sets that will need to be connected.
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Depending on the distance between the condenser and the module, there may be other components
installed in the lines. Here is a short list of components found in the lines. A filter dryer, which removes
any moisture from the refrigerant, needs to be installed close to the compressor section. A sight glass
should be installed close to the thermal expansion valve. This will help in diagnosing any problems with
the air conditioning (A/C) setup. A solenoid is required when the liquid line exceeds 75 Ft. This will
prevent the build up liquid refrigerant from entering the compressor while the unit is off. If the suction line
exceeds 75 Ft, an accumulator will need to be installed to prevent any liquid refrigerant from entering into
the compressor.
LOW PRESSURE LIQUID
EVAPORATOR CONDENSER
THERMAL
EXPANSION
VALVE SENSING BULB
LOW PRESSURE VAPOR
LOW TEMP / PSI SWITCH
SUCTION PORT
BASIC REFRIGERANT PIPING
I. There are two different types of thermal expansion valves. Internally equalized
valves will have 2 connections, one for liquid to the valve and one to the
distributor of the coil. The externally equalized will have an additional fitting for
the capped line from the coil.
II. If the coil has a hot gas bypass, install this now with the instructions included in
the kit.
B. Braze the joints. These joints will be under great pressure, so proper joint construction is
imperative. All joints need to be made using Silver-Phosphorus or Copper-Phosphorus
brazing filler, available from a local welding store. DO NOT USE SOFT SOLDER, this
material does not produce a strong enough joint. It is also recommended to flow dry
nitrogen through the lines to prevent joint oxidation while brazing.
I. Clean both mating surfaces with Emory cloth.
II. Fit both pieces together. If there are multiple joints within a short distance, clean
and fit them together as well.
III. There are some parts in the lines that cannot be overheated. Parts like the
thermal expansion valves, solenoid valves, sight glasses, and accumulators
cannot exceed 200° F. Place a wet rag around these parts to cool them while
you braze the joints, and avoid pointing the torch flame directly on these devices.
IV. Heat using a TurboTorch® or equivalent torch using MAPP gas or Acetylene.
Move the torch back and forth on the pipes. This will distribute the heat more
evenly around the part. When the parts glow a dull red, pull the torch away
slightly. Be careful not to over heat the pipe. Smaller pipes, if overheated, will
begin to melt and burn.
V. Add brazing wire until the entire joint is covered. On larger diameters of pipe,
you may need to move your torch around the diameter of the pipe.
THERMAL
EXPANSION
VALVE
SIGHT GLASS
COMPRESSOR
DRIER FILTER
HIGH-PRESSURE LIQUID
HIGH-PRESSURE VAPOR
HIGH TEMP / PSI SWITCH
HOT GAS PORT
1. Plumb Liquid and
Suction Lines.
A. Run the
lines. Keep
the lines as
short and as
straight as
possible.
Also, keep
the lines
away from
any sharp
edge. The
lines may
vibrate some
during
normal use
and this will
keep the
lines from
breaching.
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VI. If there are multiple joints to be made, move the torch and begin heating the next
joint. This will save time and fuel.
VII. Let the joints cool naturally. Cooling the joints with water could cause the joints
to fail prematurely.
2. Pressure testing the lines.
A. Charge the lines with Dry Nitrogen to design operating PSI.
B. If the pressure changes
drastically, you have a leak. If
the pressure drops slowly, you
may have a leak. If the
pressure holds for 15 minutes,
proceed to the next step.
I. Ultrasonically leak
check all joints.
II. After all joints have
been tested, bleed off
the excess pressure,
and repair the joints.
You will have trouble
repairing the joints if
there is pressure in the
lines.
III. Start the pressure
testing over.
MIC ROM ETE R
CO MPR ESS OR
GA UGE
SU CTIO N LIN E
To Vac uum Pum p (Y ellow)
LE A K TEST A N D P R EP
FOR REFRIG E R A NT C H A R G E
VA CUUM PU MP
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3. Vacuum the lines
A. Find and install the valve cores located on your compressor unit. If you cannot find the
taps, check the owner’s manual.
B. Install the pressure gauge manifold. Make sure both valves are closed on the manifold.
The blue line goes to the suction line and micron gauge. The yellow line connects to a
vacuum pump. Start the vacuum pump. To start vacuuming the system, open the blue
line side of the manifold. You should see the pressure start to drop.
C. Continue to vacuum the lines for 15 minutes, and then stop. If the vacuum on the lines
doesn’t hold, you have a leak. Repeat step 2 to fix the problem. If it holds, read the
micron gauge. If the gauge does not read below 500, continue to vacuum the lines until
the gauge does. You are now removing the moisture from the lines. This is very
important!!! The more moisture you remove now, the more efficiently your system will
run. Close the valves to the pump and the system should be able to maintain a 1000
micron vacuum continuously.
4. Installing the refrigerant. You will need a tank of
refrigerant and a scale. The scale must be able to
read ounces and have a max capacity of 50 Lbs.
The refrigerant will come from a HVAC professional.
Make sure to read the condenser owners manual
C OM P RE SS OR
for what kind of refrigerant and how much you will
need for your system. This step will be done while
the condenser is off.
A. Attach the red line to the liquid line
B. Open the valves on the unit. This will
release the holding charge into the circuit.
C. Attach the yellow hose to the tank of
refrigerant, open the valve on the tank, and
invert the cylinder on the scale.
G AU GE
SU C TIO N LI NE
To T ank (Y el low )
C H A R G IN G S Y S T E M
D. Open the blue valve on the manifold,
slightly. This will allow charge to enter into
the circuit.
S CA LE
E. Close the valve on the manifold after 80% (by weight) of the charge has been introduced.
F. RECORD THE WEIGHT OF THE TANK. This will tell you how much charge is left in the
tank.
5. Trimming the refrigerant charge. Once the initial charge has been introduced into the system,
allow the compressor to run for 15 minutes. This will balance the charge and help ensure
accurate readings.
A. Locate the charging chart in the compressor owner’s manual. Each chart will be different
depending on the manufacturer of condenser unit. Most require a liquid pressure and
temperature to be known.
B. Record the liquid line temperature and pressure. With the charging chart, plot the point
where the system is operating. Note if it falls into the Add Charge or Reduce Charge.
I. Add charge. Slowly turn the Blue side of the pressure gauge manifold. This will
allow the charge from the tank to enter the suction side of the compressor. After
a sufficient amount of refrigerant has been added, close the blue side valve and
allow the system to stabilize. Recheck temperature and pressure; re-plot the
point on the chart, and repeat the process if necessary.
II. Reduce charge. In the case of overfilling the circuitry, the excess refrigerant
must be recovered into an approved cylinder. Seek professional help for this
step.
C. Weight the tank and record the changes.
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Optional Moisture Eliminator Panel
If the unit is equipped with an optional moisture eliminator panel, the maximum face velocity of the coil
may be increased to 650 FPM. Moisture eliminator panels require minimal maintenance. Visual
inspection is recommended periodically. Scale or clogging will impair performance. If scale or clogging
occurs, remove the panel and flush with steam or water. Flushing should not have sufficient force to
dislodge the media from the panel. Scale removal may require a vinegar or detergent application
followed by rinsing
Roof Mount Installation with Blower Only Unit
Indoor Installation with Direct Fired Unit
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Electrical
WARNING!!
or Electrical Package
Before connecting power to the module, read and understand
the entire section of this document. As-built wiring diagrams
are furnished with each module by the factory, and are
attached either to the door of the unit or provided with a
paperwork packet.
Electrical wiring and connections should be done in
accordance with local ordnances and the National Electric
Disconnect power before
installing or servicing module.
High voltage electrical input is
needed for this equipment. This
work should be performed by a
qualified electrician.
Code, ANSI/NFPA70. Be sure the voltage and phase of the
power supply and the wire amperage capacity is in accordance
with the unit nameplate. For additional safety
information refer to AMCA publication 410-96, Recommended
Safety Practices for Users and Installers of Industrial and
Commercial Fans.
1. Always disconnect power before working on or near
this equipment. Lock and tag the disconnect switch or
breaker to prevent accidental power up.
2. Make certain that the power source is compatible with
the requirements of your equipment. The Air handler
wiring schematic and the compressor documentation
identifies the proper phase and voltage of the
equipment.
3. Secure the power cable to prevent contact with sharp
objects.
4. Do not kink power cable and never allow the cable to
come in contact with oil, water, grease, hot surfaces or
Copper Wire Ampacity
Wire Size AWG Maximum Amps
14 20
12 25
10 30
8 40
6 55
4 70
3 85
2 95
1 110
0 125
00 145
chemicals.
5. There are RC, Y1, and Y2 terminals for cooling in the
electrical control package or heated make up air. These terminals must be connected to the
matching terminals in the condenser.
6. Before powering up the DX module and compressing unit, make sure that the interior of the unit is
free of loose debris or shipping materials, and all refrigerant piping is complete.
Connect to Terminal RC in Heater
Stage Y1 connects to Terminal Y1
in Heater or Electrical Package
Stage Y2 connects to Terminal Y2
in Heater or Electrical Package
Terminals on Condensing Unit
Dry Contacts for Condensing Unit.
Located in Pre-wire or Heated Make-
up-air unit.
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OPERATION
Prior to starting up or operating the DX module, check all fasteners for tightness. Ensure that the coil is
clean and that the interior of the module is free of loose debris. Also, check the drain pan for proper
drainage. This will guarantee proper operation during the cooling season.
Start Up
Special Tools Required
• AC Voltage Meter
• Amperage Meter
• Standard Hand Tools
Start Up Procedure
1. Remove the access door and check all electrical connections for tightness and continuity.
2. Inspect the air-stream for obstructions.
3. Compare the supplied voltage with the unit’s nameplate voltage. If this does not match, correct
the problem.
4. Set the thermostat to a set-point cooler than the entering air temperature for start-up purposes.
The cooling circuit will be energized when the entering air temperature is hotter than the
thermostat set-point.
5. Install the access door and apply power to the unit. If the entering air temperature is hotter than
the thermostat set-point, the cooling circuit will be energized the first stage of the compressor
should turn on.
6. Locate the sight glass and observe the refrigerant flow for a few minutes. This run time will allow
the unit to stabilize. If the line has is foaming, a large quantity of bubbles, you may need to add
charge to your unit.
7. Adjust the thermostat so that the second stage turns on, a difference of 10°F (typical) is required .
Repeat step 6.
8. Set the thermostat back to the desired cooling temperature (typically about 75°F-85°F).
Remember, the cooling circuit will only be energized when the entering air temperature is higher
than the set-points.
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Component Description
Component Number
Component
Description of Operation
2 3
4
Compressor
Suction Line(s)
Liquid Line(s)
DX Coil Module
Air Handler
Intake Hood
The following table lists common components and their function inside the AC system.
1 Filter Dryer Removes moisture and small
particulate from the refrigerant
2 Sight Glass with Moisture Indicator
(optional)
3 Solenoid Valve
(required for liquid line lengths in
excess of 75 FT)
4 Thermal Expansion Valve Controls the amount of liquid
5 Thermal Expansion Valve Bulb Senses the suction line
Allows for viewing of refrigerant
flow and moisture content
Valve, wired in parallel to the
signal lines, blocks the flow of
liquid refrigerant back into the
compressor during reset.
refrigerant flowing into the coil,
with the use of a capillary bulb.
temperature and adjusts
refrigerant flow accordingly
lines
1
5
Typical Installation of an AC system
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Troubleshooting
The following table lists causes and corrective actions for possible problems with DX coil modules.
Review this list prior to consulting manufacturer.
Troubleshooting Chart
Problem
Insufficient Cooling Frozen coil Reduce refrigerant charge.
Insufficient Airflow
Excessive Airflow
Water in ductwork Drip pan full Check drip pan for obstructions.
* Air velocity should be maintained between 200 and 550 FT per Minute through the coil.
Potential Cause
Charge is low Add refrigerant charge.
Excessive air flow Slow blower RPM down.
Contaminated refrigerant Have refrigerant replaced.
Frozen coil Reduce refrigerant charge.
Coil sized too small *
Overestimation of static pressure Reduce blower rpm.
Coil sized too large *
Excessive airflow Slow blower RPM down.
Ductwork is not insulated
Corrective Action
Check for proper airflow across
coil.
Increase airflow across coil.
Replace module with larger coil.
Change motor HP.
Slow blower RPM down.
Check drip pan plumbing for
clogs.
Insulate ductwork to reduce
condensation.
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MAINTENANCE
To guarantee trouble free operation of this DX coil module, the manufacturer suggests following these
guidelines. Most problems associated with unit failures are directly related to poor service and
maintenance.
Please record any maintenance or service performed on this equipment in the documentation section
located at the end of this manual.
WARNING: DO NOT ATTEMPT MAINTENANCE ON THE DX MODULE OR
COMPRESSOR UNIT UNTIL THE ELECTRICAL SUPPLY HAS BEEN COMPLETELY
DISCONNECTED
General Maintenance
1. Inlet and approaches to DX module and compressor unit should be kept clean and free from any
obstruction.
2. All fasteners should be checked for tightness each time maintenance checks are preformed prior
to restarting unit.
3. DX coil modules require little attention when moving clean air. Occasionally, dust may
accumulate on the coil causing low airflow or reduced cooling. The DX coil should be inspected
and cleaned every 6 months during the cooling season.
Every 6 months
1. Check and clean the drainage pan and drain.
2. Clean the DX coil from the entering air side. This will keep any grit or particulate from lodging it’s
self deeper into the coil. The air deflection screen must be removed before cleaning.
Yearly
1. Check the coil for damage. If there is evidence of a leak, seek professional help.
2. Check the moisture indicator inside the sight glass. If the indicator reads wet, call a professional
for more information and repair.
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Start-Up and Maintenance Documentation
START-UP AND MEASUREMENTS SHOULD BE PERFORMED AFTER THE SYSTEM HAS BEEN
AIR BALANCED (Warranty will be void without completion of this form)
Job Information
Job Name Service Company
Address Address
City City
State State
Zip Zip
Phone Number Phone Number
Fax Number Fax Number
Contact Contact
Purchase Date Start-Up Date
DX coil Information
Refer to the start-up procedure in this manual to complete this section.
Name Plate and Unit Information
Model Number
Serial Number
Volts
Hertz
Phase
Tonnage
Refrigerant Line
Suction(1/ 2) /
Field Measured Information
Refrigerant type
Refrigerant volume Lbs.
Airflow Direction Correct
Incorrect
Pressures
Liquid (1/ 2) /
Maintenance Record
Date Service Performed
Factory Service Department
Phone: 1-866-784-6900
Fax: 1-919-554-9374
16 April, 2013 Rev. 12
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