Optima Cooler Air and
Electric Defrost Units
Instruction Manual

General safety information

**** All installation and maintenance procedures should be performed by qualified personnel already familiar with the equipment.
All field wiring should match the requirements of the equipment, as well as any local or national codes.
Coil edges and other sharp objects should be met with caution, as they can cause serious injury. Fan blades are especially sharp, and therefore should be handled only while wearing protective gloves.
High temperatures can cause damage to the equipment. The expansion valve must be covered in heat absorbent material and the suction line sensing bulb removed while brazing the refrigerant connections.
Never use the refrigeration compressor to evacuate the equipment. Never start the refrigeration compressor if it is in a vacuum.
Fan motors are sealed and do not need lubrication
All power sources should be disconnected before any type of service work is performed on the equipment. For cleaning the equipment, remove and reinstall the drain pan after every cleaning session. Failure to follow these steps can result in damaged equipment or personal injury.
Inhalation of certain refrigerants can be harmful, or even fatal. Failure to implement proper detection devices, ventilation, and procedures can result in serious injury or death. Ventilation of all refrigerants should follow all related regulations, as certain refrigerants are harmful to the environment. For more information, refer to any local or national codes that may apply.

Inspection

Each shipment should be carefully checked against the bill of loading at the time of receipt. The shipping receipt should not be signed until all items listed on the bill of loading have been accounted for. Check carefully for any damage. Any and all shortages or damages should be reported to the delivery carrier. Damaged equipment during shipment becomes the delivery agent’s responsibility and should not be returned unless prior approval has been given by Danfoss. The equipment is pressurized with 29 psi (2 Bar) of dry air during manufacturing.
If the unit lost pressure during transportation, contact the warranties department: USwarranty@danfoss.com

For special requirements please contact our factory.

Unloading

Special care should be taken while unpacking or uncrating the equipment so that damage and injury can be prevented. Heavy equipment should be kept on the original pallet until ready for final installation. While using lifting straps, ensure to use a spreader bar and make sure the straps do not compress the metal construction. When using a forklift, make sure the unit is positioned as shown in the following image.

Pallet

Mounting

The equipment can be mounted using od hangers, lag screws, and/or bolts made of stainless steel to prevent galvanic corrosion. Units should be hung with no degree of inclination so that the condensate drainage works properly. Proper airflow through the unit is essential for efficient performance and maintenance of design storage temperatures. Never install an evaporator over a doorway.

Mounting reference DACC

Note: 1.1xH or greater is critical for proper performance
n = number of units to install
Lr = length of room

Unit Dimensions

Notes

• Do not place the cooler directly over or next to a door.
• Do not place the product directly in front of the cooler.
• The air cooler should have a free air discharge for air throw.
• Do not place coolers in front of each other at a distance less than their air throw indicated in the technical specification sheet.
•  In the case of electric defrost units; make sure to leave a free space of at least the length of the unit on the electric connection side to remove the heaters in case of failure.
• The minimum distance between air defrosts units must be 39.4 in.
• If you have reduced space or special room construction, please contact your local sales office to receive the correct advice on unit mounting.
• This unit cooler should have free air discharge and be located below flat ceilings to achieve rated air throw.

Refrigerant piping

The type, sizing, and installation of all piping must be in accordance with the recommended and accepted practices for refrigeration applications. All low-temperature piping should also be insulated in accordance with standards ASHRAE. Suction traps should be used when and if the suction line rises above the unit cooler. On horizontal lines, the good practice installations recommend a minimum slope according to ASHRAE. It is recommended to have a slope of at least 1/4 inches (0.63 cm) by 10 feet (304.8 cm) in length in order to return the oil to compressors.

Expansion valve

For direct expansion units, select an expansion valve in accordance with capacity data and as required by the expansion valve manufacturer.
Expansion valves with external equalizers should be used. After the temperature has reached design conditions, adjust the expansion valve to obtain 8 to 10º F superheat at the suction line. Expansion valves are to be installed in accordance with the specific manufacturer’s recommendations. Units that require an externally equalized expansion valve must have that line connected. The proper location of the bulb is extremely important to the performance of the coil. Good thermal contact with the suction line is also essential. On solder-type valves, a wet cloth wrapped around the valve during installation will protect it from overheating and damage. On multiple evaporator systems, the piping should be arranged such that the flow from any valve cannot affect the bulb of another.

Drain line

All drain lines subject to freezing temperatures must have drain line heaters and be insulated. Drain line traps must also be heated to prevent freezing up of the drain line and trap. It is recommended that drain traps be installed outside of the conditioned space. The drain line must have a slope level and look for the nearest exit to the outside.

Wiring
All wiring must be done in strict accordance with local and national electrical codes. Fan motor(s), local isolators, electrical heater elements, and controllers must be wired in accordance with the electrical wiring diagrams provided. Use copper conductors of appropriate size only.
All electrical installations should only be performed by qualified and authorized personnel.

**** For thermal motor protection, the installed thermal contacts must be used and wired according to the circuit diagram attached to the unit.
The unit must be connected to the physical ground.

Installation

The installation and maintenance of this equipment should be performed only by qualified professional personnel who are familiar with this type of equipment. The equipment arrives from the factory pressurized with dry air. All equipment must be evacuated before charging the system with refrigerant. All field wiring should be checked and be in strict conformity with the equipment requirements, as well as all national and local codes. Use the nameplate electrical data for conductor and fuse sizing. Avoid contact with any sharp edges or sharp coil surfaces. These can be potential injury hazards. Make sure that all power sources are disconnected before any service work is done on equipment.

**** Before starting up the unit make sure all accessible electrical parts are secured!

Vacuum

A proper vacuum is essential prior to charge the refrigerant for the system. This avoids many problems that can arise due to a lack of detail within this step. The system should be checked through all cycles to ensure proper operation. ASHRAE best practices should be followed when handling vacuum and charging refrigerant.

Start-up

At start-up the following items should be checked:

• Check all threaded connections.

• Check electrical connections of motors, heater elements, and any additional components, if applicable.

• Run the fans and check the direction of rotation. Make sure that there is no transport damage.

• During the test run observe the equipment and take notice of the following:
  – Verify silent operation of the fans (bearings, contacts, balance)
  – Check power requirements of electrical motors
  – Verify the absence of Leaks
  – Adjust the expansion valve for proper superheating, if necessary

• After 24 hours of operation, re-check the equipment, especially all rotating parts.

Maintenance and service

**** Disconnect all power sources before service!

12.1 Fan motors and heaters
The only electrical components vulnerable to potential malfunction are the fan motors, control voltage regulation circuits (if applicable), and electrical defrost heaters. In the event of motor or heater failure, the affected part must be removed from the unit and replaced.
12.2 Drain pan
A periodic inspection of the drain pan is recommended. Accumulated dirt and dust should be cleaned out with hot water. If a sign of improper drainage is apparent then the drain line pitch, drain line heater (if applicable) and drain trap should be checked for proper operation. The unit can be cleaned using hot water. Special care should be taken when cleaning the unit around the electrical areas including the fan, wiring, and junction boxes. Water could potentially damage the electrical motor.
12.3 Inspection and maintenance
Verify the following points when visually inspecting the equipment:

• Secured threaded connections
• Leaks
• Silent operation of the fans
• The general state of the unit such as cleanliness and corrosion The cleaning of the finned heat exchanger is of the utmost importance to ensure smooth operation and long life of the equipment.
• There is no general rule on how often it should be cleaned. The frequency and method of cleaning depend on the customer and must be determined by the customer´s operating personnel. If necessary, the ice must be defrosted using water at 59°- 77° Fahrenheit. Never remove ice mechanically with sharp or metallic objects.
• The equipment is always supplied in a clean condition. If, during installation and/or first operation hours, contamination reaches a state where capacity can be affected, it is necessary that the unit is cleaned before operation.
  When cleaning the unit it must be out of operation and all electrical power disconnected.

12.4 Hydraulic heat exchanger cleaning

•  When cleaning with pressurized water or compressed air, the fans must be turned off. To avoid damage, never spray the fans directly!
• Clean the coil from top to bottom so that the dirt flows down. Cleaning should continue until all dirt is removed.
• Always clean / spray in the direction of the fins. Never clean at 90 ° of the fins!
• Maximum vapor pressure allowed: 6 bar. Maximum water pressure allowed before the outlet: 80 to 100 bar.

12.5 Preventive maintenance for commercial evaporators

| As required| Once a
month| Every 3
months| Every 6
months| Every year
---|---|---|---|---|---
CLEAN using a brush, pressurized water, or mild detergent. Make sure the product being used is appropriate for this particular application. NEVER USE ACID-BASED CLEANER.| | | | |
CHECK that fans rotate freely and quietly.| | •| | |
REPLACE any motor if it vibrates or makes an unusual noise.| •| | | |
INSPECT the unit for unusual vibrations in fans or housing. Identify the fan that is causing vibration.| | •| | |
INSPECT the drain pan to make sure the drain is free from obstructions, including ice buildup.| | •| | |
INSPECT for ice buildup on the coil.| | •| | |
CHECK defrost controller calibration.| •| | •| |
CHECK that heaters are working properly during defrost| | | •| |
VERIFY heater power consumption by comparing it to the data in the electrical diagram| | | | •|
CHECK that the drain line is working properly.| | •| | |
CHECK that all fan screws are tight. Tighten them if necessary.| | | | •|
CHECK that there is no corrosion in fins, pan, housing, soldered joints, or copper pipes.| | | | | •
CHECK that there are no grease stains in coil headers, return bends, or fins.| | | | | •
VERIFY there are no possible leaks.| | | | | •
CHECK that wiring is in good condition and protected. Replace protection if necessary.| | | | | •
CHECK that all ground connections are tight.| | | | | •

Troubleshooting

fuse.
1.3 Damaged timer or defrost thermostat| 1.3.1 Replace controller.
1.4 Unit in defrost cycle| 1.4.1 Wait until cycle completion.
1.5 Coil does not get cold enough to reset the thermostat| 1.5.1 Increase fan delay time after defrost cycle.
1.6 Motor s burnt| 1.6.1 Check for voltage surge and replace the motor.
1.7 Ventilator does not turn| 1.7.1 Check for any obstruction (ice, debris, etc.) and remove
| 1.7.2 Check the junction box in the fan for any short circuits and repair.
2. Room temperature too high| 2.1 Room thermostat set too high| 2.1.1 Reduce thermostat setting.
2.2 Superheat too high| 2.2.1 Check if the expansion valve is feeding correctly and clean the strainer filter. 2.2.2 Check if the bulb is placed in the correct position and adjust if necessary.
2.2.3 Adjust the superheat on the expansion valve.
2.2.4 Check for low refrigerant charge in the system.
2.3 Low refrigerant in the system| 2.3.1 Check for leaks and charge additional refrigerant in the system.
2.4 Coil blocked with ice| 2.4.1 Make manual defrost in the coil. Check to defrost the system.
2.5 Unit cooler too close to doors| 2.5.1 Relocate the unit or add a strip/air curtain to the door.
2.6 Excessive air infiltration due to open doors| 2.6.1 Check for door seals and replace them if necessary. 2.6. 2 Keep doors closed as long as possible.
2.7 Product has just been loaded into a cold room| 2.7.1 Wait until product temperature is lower.
2.8 System is turned off| 2.8.1 Turn on the refrigeration system.
2.9 Power surge in the system fails| 2.9.1 Restore power surge.
2.10 Poor air flew into the room| 2.10.1 Make sure all fans turn in the correct direction 2.10.2 See possible cause 1.7
2.10.3 See symptom 4
2.10.4 Check unit location recommendations
211 Pressure drop across evaporator too high.| 2.11.1 Replace the expansion valve with a valve having external pressure
equalization, adjust superheat on the valve
2.12 Lack of subcooling in the system| 2.12.1 Establish subcooling in the system.
2.13 Pressure drop across the valve is larger than the design pressure of the valve| 2.13.1 Select a new valve with the desired pressure drop.
2.14 Expansion valve is blocked with ice due to moisture in the system| 2.14.1 Change the drier filter and clean the ice off the valve.
2.15 Expansion valve is blocked with wax or other impurities| 2.15.1Clean valve port and strainer.
2.15.2 Clean the solenoid valve and its filter.
2.15.3 Replace the oil in the refrigeration system.
2.16 Expansion valve is too small| 2.16.1 Select and replace the valve with a higher capacity valve or orifice.
2.17 Expansion valve bulb charge lost| 2.17.1 Replace valve
2.18 Incorrect selection of the powerhead of the expansion valve| 2.18.1 Select a powerhead according to the application.
2.19 Expansion valve bulb is not making good contact with the suction line.| 2.19.1 Fasten bulb to suction line appropriately.
2.20 Expansion valve bulb is not insulated| 2.20.1 Place insulation over the whole bulb
2.21 Expansion valve bulb is located near large valves, flanges, headers, or rising pipe.| 2.21.1 Replace expansion valve with external pressure equalization, and adjust valve overheating.
3. Ice buildup on the ceiling around the evaporator
and/or on fan nozzles, blades, or grill| 3.1 Defrost cycle is too long.| 3.1.1 Decrease defrost cycle.
3.2 Fan delay not working after defrosting cycle.| 3.2.1 Adjust defrost thermostat correctly or go to 33
3.3 Defective defrost thermostat or timer.| 3.3.1 Replace component.
3.4Too many defrost.| 3.4.1 Reduce the number of defrosting per day.
4. Coil not clearing frost after defrosting cycle| 4.1 Heater not working.| 4.1.1 Make sure all heaters are working.
4.2 Hot gas supply is not enough.| 4.2.1 Make sure there is sufficient hot gas volume to defrost the unit.
4.3 Not enough defrost cycles per day.| 4.3.1 Increase the number of defrost cycles per day.
4.4 Defrost cycle is too short.| 4.4.1 Increase time on defrost thermostat or timer for a longer cycle.
4.5 Defrost the thermostat or timer not working.| 4.5.1 Replace component
5. Uneven coil frosting during refrigeration
cycle| 5.1 Distributor in the horizontal position.| 5.1.1 Change distributor to a vertical position.
5.2 Distributor or capillaries are blocked.| 5.2.1 Replace distributor with capillaries.
5.3 After defrosting dripping time is too short.| 5.3.1 Increase time for dripping.
5.4 incorrect or missing distributor nozzle.| 5.4.1 Add or replace the nozzle with an appropriate size orifice for conditions.
5.5 Located too close to the door opening.| 5.5.1 Relocate evaporator
6. Ice accumulation on the drain pan| 6.1 Drain line heater not working.| 6.1.1 Check hater power supply. 6.1.2 Change drain line heater.
---|---|---
62 Tray heater not working.| 6.2.1 Check heater power supply 6.2.2 Change drain line heater
63 Unit tilted unproperly.| 6.3.1 Level unit to a horizontal position.
6.4 Drain line plugged.| 6.4.1 Clean drain line.
6.4.2 Insulate drain line properly (if blocked with ice)
6.6Thermostat not working.| 6.6.1 Replace defective component.
6.7 Drain line without water tramp| 6.7.1 Install water tramp in drain line outside the cold room
6.8 Drain pan was not placed properly in the unit after maintenance.| 6.8.1 Make sure the drain pan is close to the heaters or hot gas coil.
7. Water accumulation on drain pan or water spreading outside unit| 7.1 Drain line plugged.| 7.1.1 Clean drain line.
72 Drain pan not placed properly in the unit after
maintenance.| 7.2.1 Make sure the drain pan is leveled towards the back
73 Unit tilted unproperly.| 7.3.1 Level unit to a horizontal position.

Spare parts

Reference data

Service record Danfoss Unit Cooler
One data sheet must be completed for each installation and each cooler, with a copy for the owner, a copy for the installer, and the original or Danfoss. If another company is to provide the service and maintenance, additional copies should be prepared as necessary

Danfoss Unit Cooler

System reference data
The refrigeration installation contractor must complete and sign the information below:
Date of installation of system___
Installer name and address ____

Evaporator(s)
Evaporator Model No.____
Evaporator Serial Number____
Electrical System Volts _ Phases___
Expansion valve brand and model _
Ambient at startup __ °F
Box design temperature __ °F
Box operating temperature ___ °F
Thermostat setting __ °F
Defrost setting _ / day__minutes fail proof _ / day ____ minutes fail proof.
Evaporator suction line temperature _ °F
Superheat at evaporator ___ °F
Discharge __ No. of times ____ Final Microns _ No. of times ___ Final Microns __
Evaporator drain line with trap external to box Yes • No •

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Danfoss A/S Climate Solutions
danfoss.us
+1 888 326 3677
heating.cs.na@danfoss.com

Any information, including, but not limited to information on the selection of the product, its application or use, product design, weight, dimensions, capacity, or any other technical data in product manuals, catalogs descriptions, advertisements, etc., and whether made available in writing, orally, electronically, online or via download, shall be considered informative and is only binding if and to the extent, explicit reference is made in a quotation or order confirmation. Danfoss cannot accept any responsibility for possible errors in catalogs, brochures, videos, and other material. Danfoss reserves the right to alter its products without notice. This also applies to products ordered but not delivered provided that such alterations can be made without changes to the form, fit, or function of the product. All trademarks in this material are property of Danfoss A/S or Danfoss group companies. Danfoss and the Danfoss logo are trademarks of Danfoss A/S. All rights reserved.

AN378367211987en-US0101
© Danfoss
Climate Solutions

Documents / Resources

| Danfoss Optyma Cooler Air and Electric Defrost Units [pdf] Instruction Manual
Optyma Cooler, Air and Electric Defrost Units, Optyma Cooler Air and Electric Defrost Units, AN378367211987en, US0101
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