Greenheck IGX Installation Manual

Page 1

Part #474681

Packaged DX Module

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!

As used in Greenheck models

•DGX

•IGX

•MSX

Recognized Component

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 Electric Code (CEC) in Canada.

2. Unit must be securely and adequately grounded.

3. Verify that the power source is compatible with the equipment.

4. Never open access doors to the unit while it is running.

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 and ventilate 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 DX Module for Make-Up Air

Page 2

Receiving

This module is installed as a component of a makeup air unit and does not require any special handling. Refer to the Receiving portion of the unit Installation, Operation and Maintenance (IOM) Manual for complete instructions on receiving, unpacking and handling.

Unpacking

The unit is shipped as a complete installed unit. Protective coverings have been installed on the face of the condenser coil that should be left in place until installation of the unit is complete. The only item that was shipped loose with the unit is the P Trap kit. Verify that the P Trap kit has been received. Refer to Unpacking instructions in unit IOM.

Handling

Units are to be rigged and moved by the lifting brackets provided. Do not forklift. Refer to the Handling portion of the unit IOM for complete instructions on handling.

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 during storage. The manufacturer will not be responsible for damage during storage. The following suggestions are provided solely as a convenience to the user.

Inspection and Maintenance During Storage

While in storage, inspect units once per month. Keep a record of inspection and maintenance performed. If moisture or dirt accumulations are found on the parts, the source should be located and eliminated. At each inspection, rotate all moving parts by hand ten to ﬁfteen revolutions to distribute lubricant on motor and bearings. 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 preventative should be restored to good condition promptly if signs of rust occur. Immediately remove the original rust preventative coating with petroleum solvent and clean with lint-free cloths. Polish any remaining rust from the surface with crocus cloth or ﬁne emery paper and oil. Do not destroy the continuity of the surfaces. Wipe clean thoroughly with Tectyl® 506 (Ashland, Inc.) or the equivalent. For hard to reach internal surfaces or for occasional use, consider using Tectyl® 511M Rust Preventative or WD-40® or the equivalent.

Table of Contents

General Safety Information ...................1

Receiving, Handling, Storage .................2

Product Overview ...........................2

Subassemblies ..............................3

Coils .....................................3

Dampers ..................................3

DX System ................................3

Installation

Service Clearances ..........................4

Additional Clearances for Packaged DX Units ....4

Lifting ....................................4

Condensate Drain (P Trap) ....................4

Switch S4 .................................4

Component Operation

Compressor Components ....................5

Electrical Components .......................5

Refrigerant Components .....................5

Additional Control Components ...............5

Factory Installed Refrigeration System

Components ...............................6

Sequence of Operation

Control Sequence ...........................7

Optional Variable Air Volume ..................7

Start-Up Unit

Model and Serial Number ....................8

Pre-Start-Up Checklist .......................9

Special Tools Required ......................9

Voltage Imbalance ..........................9

Start-Up Checklist .........................10

Troubleshooting

Refrigeration Circuit .....................11-14

Routine Maintenance

Monthly ..................................15

Annually .................................15

Maintenance Procedures ....................15

Reference

Component Location .......................15

Maintenance Log ....................Backcover

Warranty ...........................Backcover

Packaged DX Module for Make-Up Air Unit

Page 3

Product Overview

Subassemblies:

The Packaged DX Module for make-up air is a horizontally conﬁgured unit that is installed as a package in make-up air units and is designed for outdoor installations. The Packaged DX Module is used to temper the air that is supplied to the building. The make-up air unit is designed to provide sufﬁcient air to replace air that is exhausted from the building and this module is designed to provide necessary cooling.

The DX system comes fully charged with R-410A refrigerant from the factory and is ready for operation upon arrival.

Units may be supplied with one or two compressors based on required cooling capacity. All units with multiple compressors allow for staging of compressors to meet a wider range of outdoor air loads while reducing the number of cycles per compressor.

Compressed Refrigerant

All packaged DX modules are charged with environmentally friendly R-410A compressed refrigerant. Do not use tools or parts designed for other refrigerants on this unit.

Safety Listing

Make-up air units are listed per ANSI/UL 1995, Heating and Cooling Equipment and are ETL Certiﬁed.

Supplemental Installation, Operation and Maintenance Manuals

Refer to the Installation, Operation and Maintenance manual for the Make-Up Air unit for additional information.

Coils

Every module is supplied with a single DX evaporator coil. If there is only one cooling circuit, then the DX coil is not divided. If two cooling circuits are speciﬁed, then the DX coil will be a split-face. A single condenser coil is attached to the exterior of the module. If more than one cooling circuit is present, that condenser coil will be of split-face conﬁguration.

Dampers

Only an inlet damper may be installed in a PDX module and it will only be found when the module is installed in either model IGX or MSX that was not ordered with an inlet damper module.

DX System

The DX system in the module is a complete, sealed unit with compressed R-410A refrigerant. It consists of one or two compressors, evaporator and condenser coils and the following integral components:

• expansion valves

• liquid line lter-drier

• service / charging valves

• moisture indicating sight glass

• crankcase heater on each compressor

Each DX system incorporates the following:

• high pressure manual reset cutout

• low pressure auto-reset cutout

Models and Capacities

The Packaged DX Module for Make-Up Air Units is manufactured in three different platform sizes, each of which has several different output tonnage options. Examine shipping documents to verify correct model of the module as received.

Platform Tonnage

H12 3, 5, 6, 8

H22 7, 9, 10

H32 10, 12, 16

Model Number

A metal plate is located on the ﬁxed panel access to the control center. The plate is marked with the Platform Type and Tonnage (for example, H12-6). Record the model number here:

Packaged DX Module for Make-Up Air Unit

Page 4

Installation

Service Clearances

All make-up air units require minimum clearances on all sides for routine maintenance. Filter replacement, drain pan inspection and cleaning, fan bearing lubrication and belt adjustment are all examples of routine maintenance that must be performed. Blower and motor assemblies and coil and ﬁlter sections are always provided with a service door or panel for proper component access. Clearances for component removal may be greater than the service clearances. Refer to submittal drawings for these clearance dimensions. See also Page 4 of this manual.

Additional Clearances for Packaged DX Units

Packaged DX units require additional service 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 and the more clearance available, the better the chance of avoiding recirculation or coil starvation. This unit should never be placed under an overhang or inside a building. A minimum of 48 inches above the condenser fans is recommended.

Lifting

All units equipped with this module are provided with either four or six lifting lugs. When the unit is being hoisted, all of the provided lugs must be used for support. Four lifting lugs are on the four corners of the unit, located at the base. In addition, there may be two more lifting lugs located at the top of the unit. The locations of those two top lugs varies somewhat from unit to unit.

Use spreader bars as shown to prevent damage to the cabinet. If top-mounted lifting lugs are present, they must be used in conjunction with the bottom-mounted lifting lugs when hoisting the unit.

Minimum 48 inches clearance

Condenser Fans

End view of make-up air unit

with Packaged DX

Condenser Fans

and

Condenser Coil

Outdoor

48 inches clearance

Air Intake

42 inches clearance

Minimum 42 inches

clearance

Condenser Coil

Indirect Gas-Fired

Furnace

Unit Control Center

Use lifting lugs on

all four corners.

Lifting Details

Install Condensate Drain (P Trap)

The only installation step that is speciﬁc to the DX module is installation and priming of the engineered P trap. Locate the P trap kit that was shipped with the unit and install the kit in accordance with the enclosed instructions.

Provide and Install Switch S4

Each Packaged DX unit requires an On/Off switch to enable the unit to run. This is a user-supplied switch that may be a toggle switch mounted in a 2 x 4 inch electric box (mounted in a position chosen by the user), or it may be a simple jumper or even a control switch installed in a remote control panel supplied by the factory. See also “Additional Control Components” on page 5 of this manual.

36 inches clearance

Packaged DX Module for Make-Up Air Unit

Page 5

Component Operation

Compressor Components

Each Packaged DX module has a complete set of compressor contactors, condenser fan contactors, relays and certain integral safety controls located in the module.

Typical Packaged DX Compressor Compartment

Electrical Components

1. High Voltage Terminal Strip

2. Compressor Relays

3. Condenser Fan Contactor 4A. Compressor Contactor (Circuit A) 4B. Compressor Contactor (Circuit B)

5. Low Voltage Terminal Strip

6. High Limit Safety Control – Direct Gas-Fired units only

Refrigeration Components

7A. Compressor (Circuit A) 7B. Compressor (Circuit B) 8A. High Pressure Sensor (Circuit A, Manual Reset) 8B. High Pressure Sensor (Circuit B, Manual Reset) 9A. Thermostatic Expansion Valve (TXV) (Circuit A) 9B. Thermostatic Expansion Valve (TXV) (Circuit B) 10A. Refrigerant Distributor (Circuit A) 10B. Refrigerant Distributor (Circuit B)

11. Condensate Drain (P trap here)

Additional Control Components

In addition to the control components located in the PDX module, various high- and low-voltage circuits are found in the Make-Up Air Unit control center. See the unit-speciﬁc wiring diagram (found in the unit control center) for complete information.

Typical Unit Control Center

1. Power Distribution Block - ﬁeld-supplied power from main disconnect switch is terminated here.

2. Phase Monitor has jumpers going to power distribution block)

3. Transformer provides 24 VAC to various low voltage devices including the Phase Monitor and to Low Voltage Terminal Strip in compressor compartment.

4. Relays RC1 and RC2 are wired to the control center in the compressor compartment.

5. Low Voltage Terminal Strip - Switch S4 terminates here.

6. Thermostat TS5 monitors outdoor air temperature and turns the DX unit on or off.

7. Inlet Air Sensor monitors the incoming air temperature and will disable the DX unit if ambient temperatures are too low.

Phase Monitor constantly checks for loss of a phase, phase unbalance or phase reversal. It requires 24 VAC to operate. When a fault is detected, it cuts off the power supply to the low voltage terminal strip, disabling all motors. It has two LED indicator lights, showing “on” and “fault”.

Switch S4 (not shown) is terminated on Low Voltage Terminal Strip 5 above. S4 is ﬁeld-supplied and ﬁeld-installed unless ordered from the factory. See the unit speciﬁc wiring diagram.

Thermostat TS5 monitors outdoor air temperature. It is ﬁeld-adjustable. If there is more than one cooling circuit, an additional controller for the second stage will be provided.

Packaged DX Module for Make-Up Air Unit

Page 6

Factory Installed Refrigeration System Components

Circuit A

Condenser Coil

Service Valve for Subcooling Gauge/ High Side Pressure Drop

1. Thermostatic Expansion Valve (TXV)

Each unit is equipped with a Thermal Expansion Valve on each refrigerant circuit. The valve controls the ﬂow of liquid refrigerant entering the evaporator coil by maintaining a constant, factory set superheat of 10°F. The valve is adjustable and is located on the side of the evaporator coil and can be accessed through the coil panel access door.

2. Refrigerant Distributor

Attached to the TXV is a refrigerant distributor. The refrigerant distributor evenly distributes the refrigerant to each circuit of the evaporator coil to provide optimum performance.

3. Evaporator Coil

The coil is located in the supply airstream. In the DX system, the liquid refrigerant is expanded in the TXV and it then ﬂows through the evaporator coil. The refrigerant enters the coil as a low temperature liquid/gas where it eventually boils into a low temperature, low pressure gas prior to going into the compressor. As the refrigerant passes through the evaporator coil, it absorbs heat from the airstream. To ensure proper operation, the coil surface must be cleaned so that air movement over the coil provides the necessary heat transfer.

Evaporator Coil

Pressure Port for Troubleshooting Reheat Valves High Side Pressure Drop

Service Valve for Superheat and Low Side Pressure

4. Low Limit Pressure Switch

The switch is installed in the suction line and disables the DX system with the suction pressure drops below the set point. The switch will auto-reset when the pressure rises above the auto-reset set point.

5. Compressors

6. Condensing Coil

7. Condenser Fans

8. High Limit Pressure Switch

The switch opens when refrigerant pressure increases above the set point in the liquid line and it then requires a manual reset.

9. Liquid Line Filter-Drier

The liquid line ﬁlter-drier prevents moisture and foreign matter from entering the expansion valve.

10. Moisture Indicating Sight Glass

During normal operating conditions, the sight glass should typically be liquid. Some gas is acceptable, but excessive bubbles may indicate improper charge or a leak in the system. A green dot indicates the moisture level in the refrigerant, while a yellow dot indicates moisture in the system and needs to be dealt with.

11-13. Access Ports

Packaged DX Module for Make-Up Air Unit

Page 7

Sequence of Operation

The compressors are energized by an outdoor air thermostat TS5, located in the unit control center. The thermostat sensor is located in the intake airstream upstream of the DX coil. The thermostat can be a single or dual stage thermostat depending on the number of compressors. The ﬁrst stage of cooling will energize when the outdoor air temperature rises above the thermostat set point plus the differential. The thermostat is factory set at 80°F with a differential of 5°F but can be ﬁeld adjusted. The second stage of cooling will energize when the outdoor air temperature rises above the second stage offset plus the differential. The second stage offset is factory set at 10°F and the second stage differential is set at 5°F. See the chart below for a graphical representation of the control operation.

To summarize the

cooling controls, the ﬁrst stage of

Adjustable

cooling will turn on at 85°F and the

(+10° F)

Differential

OFF

second stage of cooling will turn on at 95°F. The second stage of cooling will turn off at 90°F and the ﬁrst stage of cooling will turn off at 80°F.

(+5° F)

Setpoint

Temperature

(factory set at 80° F)

Adjustable

Differential

OFF

FIRST

STAGE

COOLING

OFFSET

(factory set

at 10° F)

SECOND

STAGE

COOLING

Control Sequence

1. Fan switch needs to be closed (S3) between terminals R and G.

2. Heating/Cooling switch (S4) is closed between terminal R and Y1.

3. N.O. contact on fan relay (RF) is energized and closed.

4. When the outdoor air temperature is above the set point plus the differential power passes through N.O. contacts on outdoor air thermostat (TS5) and energizes the cooling relay (RC1).

5. When the pressure switches LPS (refrigerant low pressure switch) and HPS (refrigerant high pressure switch) are in their normal state relay R10 will energize. Starting the ﬁrst stage compressor contactor.

6. When the outdoor air temperature is above the second stage offset plus the differential power passes through N.O. contacts on outdoor air thermostat (TS5) and energizes the cooling relay (RC2).

7. When the pressure switches LPS and HPS (refrigerant high pressure switch) are in their normal state relay R11 will energize, starting the second stage compressor contactor.

Control Sequence - Variable Air Volume (optional)

1. Fan switch needs to be closed (S3) between terminals R and G.

2. Heating/Cooling switch (S4) is closed between terminal R and Y1.

3. N.O. contact on fan relay (RF) is energized and closed.

4. When the outdoor air temperature is above the set point plus the differential power passes through N.O. contacts on outdoor air thermostat (TS5) and energizes the cooling relay (RC1).

6. When the outdoor air temperature is above the second stage offset plus the differential power passes through N.O. contacts on outdoor air thermostat (TS5) and energizes the cooling relay (RC2).

7. When the pressure switches LPS and HPS (refrigerant high pressure switch) are in their normal state relay R11 will energize, starting the second stage compressor contactor.

8. When the discharge air temperature drops below the low temperature set point (TS9) factory set at 55°F, the second stage compressor contactor will de-energize, turning off the second stage compressor.

9. The second stage compressor will re-energize when the discharge air temperature rises above 75°F.

Packaged DX Module for Make-Up Air Unit

Page 8

Start-Up Unit

DANGER

Electric shock hazard. Can cause injury or death.

Before attempting to perform any service or maintenance, turn the electrical power to unit to OFF

at disconnect switch(es). Unit may have multiple

power supplies.

CAUTION

Use caution when removing access panels or other

unit components, especially while standing on a

ladder or other potentially unsteady base. Access

panels and unit components can be heavy and serious injury may occur.

CAUTION

Do not operate without the filters and birdscreens installed. They prevent the entry of foreign objects such as leaves, birds, etc.

CAUTION

Do not run unit during construction phase. Damage to internal components may result and void warranty.

WARNING

• Unit was factory tested. All blowers, fans,

and compressors are set-up to run correctly

when supplied power. If any one fan is running backwards or the compressor is making loud

noises, immediately turn off the power. Switch two leads on the incoming power to the disconnect. This will ensure proper operation of the unit. Failure to comply may damage the compressors and void the warranty.

• Do not jumper any safety devices when operating

the unit. This may damage components within or cause serious injury or death.

• Do not operate compressor when the outdoor

temperature is below 40ºF.

• Do not short-cycle the compressor. Allow

5 minutes between “on” cycles to prevent compressor damage.

• DX system is charged with refrigerant. Start-up must be performed by EPA Certied Technician.

WARNING

Prior to starting up the unit, power must be

energized for 24 hours without a call for cool to allow the compressor crankcase heaters time to boil

off any liquid refrigerant present in the compressor.

Every installation requires a comprehensive start-up to ensure proper operation of the unit. As part of that process, the following checklist must be completed and information recorded. Starting up the unit in accordance with this checklist will not only ensure proper operation, but will also provide valuable information to personnel performing future maintenance. Should an issue arise which requires factory assistance, this completed document will allow unit experts to provide quicker resolve. Qualiﬁed personnel should perform start-up to ensure safe and proper practices are followed.

Unit Model No. ___________________________________

Unit Serial No. ____________________________________

Compressor 1 Model No. __________________________

Compressor 2 Model No. __________________________

Start-Up Date _____________________________________

Start-Up Personnel Name __________________________

Start-Up Company ________________________________

Phone Number ___________________________________

Packaged DX Module for Make-Up Air Unit

Page 9

Pre-Start-Up Checklist

oDisconnect and lock-out all power switches. o Remove any foreign objects that are located in the

unit.

o Check all fasteners, set-screws, and locking collars

on the fans, bearings, drives, motor bases and accessories for tightness.

o Rotate the fan wheels by hand and ensure no parts

are rubbing.

o Filters can load up with dirt during building

construction. Replace any dirty pleated filters and clean the aluminum mesh filters in the intake hood.

o Verify that non-motorized dampers open and close

properly.

o Check the tightness of all factory wiring

connections.

o Verify control wire gauge. o Verify proper drain trap installation. o Check condensing fans for any damage or

misalignment. Spin the blades and make sure they don’t contact any parts and are free turning without any resistance.

o Look over the piping system. o Inspect all coils within the unit. Fins may get

damaged in transit or during construction. Carefully straighten fins with a fin comb.

o If there is an indirect gas-fired furnace in this unit,

refer to the manual provided with this unit for PreStart-Up information.

o This unit contains a crankcase heater for each

compressor which needs power supplied to it 24hours prior to start-up. If start-up is scheduled in 24 hours, unlock the disconnect power and energize unit.

SPECIAL TOOLS REQUIRED

• Voltage Meter (with wire probes)

• Amperage Meter

• Pressure Gauges – (refrigerant)

• Tachometer

• Thermometer

• Incline manometer or equivalent

Start- Up Procedure

The unit will be in operational mode during start-up. Use necessary precautions to avoid injury. All data must be collected while the unit is running.

o Make sure Pre-Start-Up checklist is complete. o Jumper R to G, R to Y1, and R to Y2 (if applicable)

on the control board.

o Turn the disconnect on. After 3 minutes

compressors will come on. Make sure all fans and compressors are rotating the correct direction.

o Allow the unit to run until the refrigerant system

stabilizes. Approximately 5-10 minutes.

Voltage Imbalance

In a 3-phase system, excessive voltage imbalance between phases will cause motors to overheat and eventually fail. Maximum allowable imbalance is 2%. To determine voltage imbalance, use recorded voltage measurements in this formula.

Key: V1, V2, V3 = line voltages as measured VA (average) = (V1 + V2 + V3) / 3 VD = Line voltage (V1, V2 or V3) that deviates farthest from average (VA)

Formula: % Voltage Imbalance = [100 x (VA-VD)] /VA

Packaged DX Module for Make-Up Air Unit

Page 10

Start-Up Checklist

Line Voltage. Check at unit disconnect.

L1-L2 Volts L2-L3 Volts L1-L3 Volts

Condensing Fans

Condensing Fan 1 L1 Amps L2 Amps L3 Amps

Condensing Fan 2 L1 Amps L2 Amps L3 Amps

Condensing Fan 3 L1 Amps L2 Amps L3 Amps

Compressors

Outdoor Air Temperature Deg F Outdoor Air Relative Humidity % RH

Return Air Temperature Deg F Return Air Relative Humidity % RH

oCompressor 1:

________ L1 amps ________ L2 amps ________ L3 amps ________ Crankcase Heater

Superheat ________ Deg. F.

Should be between 8º and 12ºF.

Subcooling ________ Deg. F.

Should be between 12º and 17ºF.

Discharge Pressure __________ PSIG

Should be between 300 and 500 PSIG

Suction Line Pressure __________ PSIG

Should be between 100 and 135 PSIG

Liquid Line Temperature ________ Deg. F.

Suction Line Temperature ________ Deg. F.

Moisture Indicating Sight Glass

Liquid Visible Yes / No Color of Center Dot Green / Yellow

Hot Gas Bypass Operational Yes / No

oCompressor 2:

________ L1 amps ________ L2 amps ________ L3 amps ________ Crankcase Heater

Superheat ________ Deg. F.

Should be between 8º and 12ºF.

Subcooling ________ Deg. F.

Should be between 12º and 17ºF.

Discharge Pressure __________ PSIG

Should be between 300 and 500 PSIG

Suction Line Pressure __________ PSIG

Should be between 100 and 135 PSIG

Liquid Line Temperature ________ Deg. F.

Suction Line Temperature ________ Deg. F.

Moisture Indicating Sight Glass

Liquid Visible Yes / No Color of Center Dot Green / Yellow

Hot Gas Bypass Operational Yes / No

Packaged DX Module for Make-Up Air Unit

Page 11

Troubleshooting – Refrigeration Circuit

TROUBLESHOOTING NOTE

IMPORTANT

Do not release refrigerant to the atmosphere! If

Before any components are changed on the refrigeration system, the cause of the failure must be

determined. Further problems will exist unless the

true cause or problem is identified and corrected.

required service procedures include the adding or removing of refrigerant, the service technician must comply with all federal, state and local laws. The procedures discussed in this manual should only be

performed by a qualified EPA Certified Technician.

NOTE: Unit is equipped with a phase loss/phase reversal control. If system does not start, check phase of electrical supply.

The ﬁrst step is to check airﬂow conditions. (e.g. improper ductwork, atypical wet bulb / dry bulb, etc.) After these steps have been eliminated, proceed with troubleshooting by following this guide:

Symptom Possible Cause Corrective Action

Open disconnect switch or circuit breaker.

Compressor contactor not closing.

Blown fuse or tripped breaker.

Low line voltage.

Close switch and/or breaker.

Check voltage to contactor coil, transformer, slave relay, system. Replace parts as necessary.

Check for shorted wire or motor. Replace fuse after correcting problem.

Check line voltage. If more than 10% from compressor marking, correcting is necessary.

Compressor will not run or does not start

Compressor starts but cuts out on low pressure

Motor thermal protector automatically resets. Allow time

Compressor motor protector open.

(2 hours) for compressor to cool down so protector will reset. Restart and check for reason overheat occurred.

Check motor for open circuit, short circuit, grounded

Compressor defective.

windings, or burn out. Compressor may be seized; check refrigerant. If necessary, replace compressor.

If manual reset (high pressure), reset switch. (Switch

High pressure switch open or defective.

Low pressure switch open or defective.

Open room thermostat or control. (No cooling required).

opens at 600 psi and will not reset above 420 psi for R-410A). Replace if defective.

Switch will open at 50 psi and auto-close at 90 psi. Replace if defective.

Check room temperature. If temperature is proper, wait for thermostat to close.

Loose wiring. Check all wire terminals and tighten as necessary.

Low or loss of refrigerant charge.

Check refrigerant pressures and temperatures (subcooling.)

Check for dirty evaporator coil, dirty ﬁlters, dampers

Airﬂow restricted.

closed, iced evaporator coil, improper belt, check motor amps, check duct design.

Low pressure switch activates at 50 PSIG

Restriction in refrigerant line.

Check refrigerant pressures, look for frosted tubing and components indicating a restriction. Check pressure drop across the ﬁlter drier.

Defective low pressure switch. Replace.

Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service information.

Packaged DX Module for Make-Up Air Unit

Page 12

Troubleshooting – Refrigeration Circuit (continued)

Symptom Possible Cause Corrective Action

Refrigerant overcharge. Check pressures, charge by subcooling.

Compressor starts but cuts out on high pressure switch

High pressure activates at 600 PSIG

Condenser fan motor defective. Check fan motor.

Condenser coil inlet obstructed or dirty. Check coil and clearances. Clean coil if necessary.

Air or non-condensables in system.

Check high side equalized pressures, check thermal expansion valves.

Defective high pressure switch. Replace.

Restriction in discharge or liquid line.

Check refrigerant line pressures, check thermal expansion valves, replace any defective component.

Condensing fan relay not pulling in. Replace.

Low voltage. Check voltage.

Compressor cuts out on thermal overload

Compressor hums, but will not start

Sustained high discharge pressure.

High suction and discharge pressures.

Defective compressor overload.

Check running amperage and conditions described under “low suction pressure” symptoms.

Check thermal expansion valve setting, check for air in system. Check air conditions and cfm.

If compressor is hot, allow compressor to cool for two hours. Recheck for open circuit.

Improper refrigerant charge. Check subcooling.

Improperly wired. Review wiring schematics.

Loose wiring. Check all connections.

Defective start relay. Replace relay.

Motor windings damaged. Verify amp draw.

Improperly wired. Review wiring schematics.

Low line voltage. Check voltage.

Loose wiring. Check all connections.

Defective start relay. Replace relay.

Motor winding damaged. Verify amp draws. Replace compressor if necessary.

Internal compressor mechanical damage.

Replace.

Refrigerant overcharge. Check pressures and subcooling.

Check thermal expansion valve setting. Check for refrigerant overcharge.

Dampen tubing vibration by taping or clamping. Carefully bend tubing away from contact where possible.

Compressor

Liquid ﬂoodback.

Tubing rattle.

noisy or vibrating

Scroll compressor rotating in reverse. (3-phase)

Check high and low side pressures during operation to conﬁrm. Rewire for opposite rotation.

Damaged compressor. Replace the compressor.

Improper mounting on unit base.

Check that compressor is properly isolated and mounting bolts are tight.

Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service information.

Packaged DX Module for Make-Up Air Unit

Page 13

Troubleshooting – Refrigeration Circuit (continued)

Symptom Possible Cause Corrective Action

High suction pressure

High discharge pressure

Excessive load on evaporator coil.

Check for high entering wet bulb temperature, check for excessive air ﬂow.

Check the thermal expansion valve, ensure bulb is

insulated. Check superheat. If superheat is high, then Expansion valve sensing bulb not secured to suction line.

valve is choking refrigerant ﬂow.

• Check bulb for contact.

• Adjust valve for superheat ~10°F.

• Replace valve power head or valve.

Thermostatic expansion valve. Overfeeding.

Check bulb location and clamping. Adjust superheat.

Replace expansion valve power head.

Overcharged. Check pressures and subcooling.

Thermal expansion valve setting.

Air inlet to condenser dirty or obstructed.

Check thermal expansion setting and calibrate

superheat/subcooling.

Check for proper clearances and possible air

recirculating. Clean coil.

Condenser fan motor defective. Check condenser fan motor.

Too much refrigerant. Check subcooling. Remove excess refrigerant.

Non-condensable in system. Remove non-condensable from system.

Dirty condenser coil. Clean condenser coil.

Condenser fan not running or running backwards.

Check electrical circuit and fuse. Check fan cycling

controls.

High load conditions. Add more equipment or reduce load.

Refrigerant undercharge/loss of refrigerant charge.

Blower running backward.

Check pressures and subcooling.

Conﬁrm blower rotation. If reversed, interchange any two

wires from 3-phase disconnect.

Loose blower, pulley or belts. Check drive pulley alignment, belt tension.

Low suction

Low entering air temperature. (Low load conditions).

Refrigerant leak. Check system for leaks. Repair leaks and add refrigerant.

Check entering air wet bulb conditions.

pressure

Evaporator dirty or iced-up, or airﬂow restricted.

Clean the coil. Check fan operation. Check airﬂow.

Plugged liquid line ﬁlter-drier. Replace ﬁlter-drier, check psi across ﬁlter.

Improper hot gas bypass setting. Check setting and correct as required.

Expansion valve defective, superheat too high or valve too small.

Adjust valve for proper superheat or replace the

expansion valve if too small or defective.

Moisture in system, check sight glass. Reclaim refrigerant, check for leaks, recharge.

Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service information.

Packaged DX Module for Make-Up Air Unit

Page 14

Symptom Possible Cause Corrective Action

Check subcooling, check for leak. Repair leak and add refrigerant.

Check superheating and adjust thermal expansion valve.

Check condenser controls and reset to obtain desired condensing temperature.

Check thermostat, check heat anticipator setting.

Check thermal expansion valve setting. Check for refrigerant overcharge. Check crankcase heater operation.

Check equalized high side pressure with equivalent outdoor temperature.

Check airﬂow, check ﬁlters, check drive for loose parts or belts. Check VFD control signal for proper operation.

Check bulb of thermal expansion valve.

Check valve. If defective, replace.

Low discharge pressure

Compressor short cycles

Compressor loses oil

Not enough cooling or lack of cooling

Liquid line is frosted or wet

Suction line is frosting

Frost on evaporator coil

Insufﬁcient refrigerant charge.

Defective or improperly adjusted expansion valve.

Low suction pressure. See “low suction pressure”.

Faulty condenser temperature controls. (Condensing fan cycle switch).

Thermostat location or controls malfunction.

Improper refrigerant charge. Check subcooling, verify superheat.

Defective high or low pressure control. Check high or low pressure switch.

Poor air distribution. Check ductwork for recirculating.

High discharge pressure. See “high discharge pressure”.

Low airﬂow at evaporator(s). Check blower operation and airstream restrictions.

Incorrect unit selection (oversized). Contact factory.

Refrigerant leak. Check system for leaks. Repair leaks and add refrigerant.

Short cycling. Check low pressure control settings.

Refrigerant ﬂood back.

Reheat ﬂush cycle inadequate. Contact factory.

Refrigeration undercharged. Check subcooling. Adjust charge, if necessary.

Dirty ﬁlter or evaporator coil. Check ﬁlter, coil and airﬂow.

Dirty or clogged condenser coil. Check coil and airﬂow.

Air or other non-condensables in system.

Restriction in suction and liquid line. Check for restrictions in refrigerant circuit.

Control contacts stuck. Check wiring.

Excessive load. Add more equipment or reduce room load.

Restriction in liquid line. Clear restriction upstream of point of frosting.

Insufﬁcient evaporator airﬂow.

Malfunctioning or defective expansion valve.

Hot gas bypass valve not functioning properly.

Manual hot gas bypass valve closed. Open valve.

Low load or airﬂow. Increase airﬂow, check ﬁlters.

Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service information.

Packaged DX Module for Make-Up Air Unit

Page 15

Routine Maintenance

DANGER

Electric shock hazard. Can cause injury or death.

Before attempting to perform any service or maintenance, turn the electrical power to the unit

to OFF at disconnect switch(es). Unit may have

multiple power supplies.

CAUTION

Use caution when removing access panels or other

unit components, especially while standing on a

ladder or other potentially unsteady base. Access

panels and unit components can be heavy and serious injury may occur.

This unit requires minimal maintenance to operate properly. To ensure proper operation and longevity, the following maintenance schedule should be followed. The items in this list assume a relatively clean air environment and may require attention more frequently in a dusty or dirty area. If this unit contains an indirect gas-ﬁred heater, refer to the Installation, Operation and Maintenance manual provided with the unit for maintenance purposes. An EPA Certiﬁed Technician should complete all refrigeration systems checks.

Maintenance Frequency:

Monthly

1. Condensate Drain Inspect and clean. Reﬁll with water or glycol.

Annually

It is recommended that the annual inspection and maintenance occur at the start of the cooling season. After completing the checklist, follow the unit start-up checklist provided in the manual to ensure the refrigeration system operates in the intended manner.

1. Door Seal Check if intact and pliable.

2. Wiring Connections Check all connections for tightness.

3. Cabinet Check entire cabinet, inside and out, for dirt

build-up or corrosion. Remove accumulated dirt, remove any surface corrosion and coat the area with appropriate ﬁnish.

4. Evaporator Coil Maintenance Check for cleanliness. Clean if required.

5. Condenser Coil Maintenance Check for cleanliness. Clean if required.

6. Condensate Drain Inspect and clean. Reﬁll with water.

7. Condensing Fan Blades and Motors Check for cleanliness. Check all fasteners for tightness. Check for fatigue, corrosion and wear.

Maintenance Procedures:

Lubrication

Check all moving components for proper lubrication. Apply lubricant where required. Any components showing excessive wear should be replaced to maintain the integrity of the unit and ensure proper operation.

Dampers

Check damper (if present) to ensure it opens and closes properly and without binding. Apply power to motorized dampers to ensure the actuator opens and closes the damper as designed.

Reference - component location

Condenser Fans

and Condenser Coil

Evaporator Coil

Direct Gas-Fired Burner

Outdoor

Air Intake

Unit Control Center

Model DGX Make-Up Air Unit

Condenser Fans

and Condenser Coil

Outdoor

Air Intake

Evaporator Coil

Outdoor

Air Intake

and Condenser Coil

Model IGX Make-Up Air Unit

Condenser Fans

and Condenser Coil

Evaporator Coil

Model MSX Make-Up Air Unit

with Electric Heat

Indirect Gas-Fired

Furnace

Unit Control Center

Unit Control

Center

Packaged DX Module for Make-Up Air Unit

Page 16

Maintenance Log

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Date __________________ Time _____________ AM/PM

Notes:___________________________________________

_________________________________________________

Warranty

Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one year from the shipment date. Any units or parts which prove to be defective during the warranty period will be replaced at our option when returned to our factory, transportation prepaid. Motors are warranted by the motor manufacturer for a period of one year. Should motors furnished by Greenheck prove defective during this period, they should be returned to the nearest authorized motor service station. Greenheck will not be responsible for any removal or installation costs.

As a result of our commitment to continuous improvement, Greenheck reserves the right to change speciﬁcations without notice.

AMCA Publication 410-96, Safety Practices for Users and Installers of Industrial and Commercial Fans, provides additional safety information. This publication can be obtained from AMCA International, Inc. at www.amca.org.

Phone: (715) 359-6171 • Fax: (715) 355-2399 • E-mail: gfcinfo@greenheck.com • Website: www.greenheck.com