Xylem Flygt 2250 User manual

Flygt 2250
Installation,
Operation, and
Maintenance Manual

Table of Contents
Introduction and Safety.........................................................................................................................3
Introduction..........................................................................................................................................3
Safety terminology and symbols.......................................................................................................3
Product warranty.................................................................................................................................4
Spare parts........................................................................................................................................5
Safety.....................................................................................................................................................5
User safety............................................................................................................................................5
Hazardous liquids.............................................................................................................................6
Wash the skin and eyes....................................................................................................................6
Environmental safety...........................................................................................................................6
Transportation and Storage..................................................................................................................7
Inspect the delivery.............................................................................................................................7
Inspect the package.........................................................................................................................7
Inspect the unit..................................................................................................................................7
Transportation guidelines..................................................................................................................7
Precautions........................................................................................................................................7
Position and fastening......................................................................................................................7
Lifting..................................................................................................................................................7
Temperature ranges for transportation, handling and storage....................................................7
Handling at freezing temperature..................................................................................................7
Unit in as-delivered condition.........................................................................................................8
Lifting the unit out of liquid.............................................................................................................8
Storage guidelines..............................................................................................................................8
Storage location................................................................................................................................8
Long-term storage............................................................................................................................8
Product Description...............................................................................................................................9
Products included...............................................................................................................................9
Pump design........................................................................................................................................9
Monitoring equipment.......................................................................................................................9
The data plate....................................................................................................................................10
Product denomination......................................................................................................................10
Installation.............................................................................................................................................12
Install the pump.................................................................................................................................12
Sedimentation prevention.............................................................................................................12
Discharge line requirements.........................................................................................................12
Fasteners.........................................................................................................................................13
Install with S-installation.................................................................................................................13
Make the electrical connections......................................................................................................14
General precautions.......................................................................................................................14
Requirements..................................................................................................................................14
Cables..............................................................................................................................................15
Earthing (Grounding).....................................................................................................................15
Earth (ground) conductor length.................................................................................................15
Connect the motor cable to the pump........................................................................................15
Cable charts....................................................................................................................................17
Connection locations.....................................................................................................................17
Color code standard......................................................................................................................18
View of terminal board and sensor connections........................................................................19
Motor cable, stator leads and thermal contacts connection to terminal board.....................20
Table of Contents
Flygt 2250 Installation, Operation, and Maintenance Manual 1

Check the impeller rotation.............................................................................................................21
Operation..............................................................................................................................................22
Precautions.........................................................................................................................................22
Distance to wet areas........................................................................................................................22
Noise level..........................................................................................................................................22
Start the pump...................................................................................................................................22
Clean the pump.................................................................................................................................23
Maintenance.........................................................................................................................................24
Precautions.........................................................................................................................................24
Maintenance guidelines...................................................................................................................24
Torque values....................................................................................................................................24
Service................................................................................................................................................25
Inspection........................................................................................................................................25
Major overhaul................................................................................................................................27
Change the oil...................................................................................................................................27
Empty the oil...................................................................................................................................27
Fill with oil........................................................................................................................................28
Replace the impeller.........................................................................................................................28
Remove the impeller......................................................................................................................28
Install the impeller..........................................................................................................................28
Adjust the impeller.........................................................................................................................29
Replace the diffuser.......................................................................................................................30
Replace the upper diffuser............................................................................................................30
Troubleshooting...................................................................................................................................32
Introduction.......................................................................................................................................32
The pump does not start..................................................................................................................32
The pump does not stop when a level sensor is used.................................................................33
The pump starts-stops-starts in rapid sequence...........................................................................33
The pump runs but the motor protection trips.............................................................................34
The pump delivers too little or no water........................................................................................34
Technical Reference............................................................................................................................36
Application limits...............................................................................................................................36
Motor data..........................................................................................................................................36
Specific motor data...........................................................................................................................36
Dimensions and weights..................................................................................................................37
Performance curves..........................................................................................................................38
Table of Contents
2 Flygt 2250 Installation, Operation, and Maintenance Manual

Introduction and Safety
Introduction
Purpose of this manual
The purpose of this manual is to provide necessary information for:
• Installation
• Operation
• Maintenance
CAUTION:
Read this manual carefully before installing and using the product. Improper use of the
product can cause personal injury and damage to property, and may void the warranty.
NOTICE:
Save this manual for future reference, and keep it readily available at the location of the
unit.
Safety terminology and symbols
About safety messages
It is extremely important that you read, understand, and follow the safety messages and
regulations carefully before handling the product. They are published to help prevent
these hazards:
• Personal accidents and health problems
• Damage to the product
• Product malfunction
Hazard levels
Hazard level Indication
DANGER: A hazardous situation which, if not avoided, will result in
death or serious injury
WARNING: A hazardous situation which, if not avoided, could result
in death or serious injury
CAUTION: A hazardous situation which, if not avoided, could result
in minor or moderate injury
Introduction and Safety
Flygt 2250 Installation, Operation, and Maintenance Manual 3

Hazard level Indication
NOTICE:
• A potential situation which, if not avoided, could
result in undesirable conditions
• A practice not related to personal injury
Hazard categories
Hazard categories can either fall under hazard levels or let specific symbols replace the
ordinary hazard level symbols.
Electrical hazards are indicated by the following specific symbol:
Electrical Hazard:
These are examples of other categories that can occur. They fall under the ordinary hazard
levels and may use complementing symbols:
• Crush hazard
• Cutting hazard
•Arc flash hazard
Product warranty
Coverage
Xylem undertakes to remedy defects in products from Xylem under these conditions:
• The faults are due to defects in design, materials, or workmanship.
• The faults are reported to an Xylem representative within the warranty period.
• The product is used only under the conditions described in this manual.
• The monitoring equipment incorporated in the product is correctly connected and in
use.
• All service and repair work is done by Xylem-authorized personnel.
• Genuine Xylem parts are used.
• Only Ex-approved spare parts and accessories authorized by Xylem are used in Ex-
approved products.
Limitations
The warranty does not cover defects caused by these situations:
•Deficient maintenance
• Improper installation
•Modifications or changes to the product and installation made without consulting
Xylem
• Incorrectly executed repair work
• Normal wear and tear
Xylem assumes no liability for these situations:
• Bodily injuries
• Material damages
• Economic losses
Warranty claim
Xylem products are high-quality products with expected reliable operation and long life.
However, should the need arise for a warranty claim, then contact your Xylem
representative.
Introduction and Safety
4 Flygt 2250 Installation, Operation, and Maintenance Manual

Spare parts
Xylem guarantees that spare parts will be available for 10 years after the manufacture of
this product has been discontinued.
Safety
WARNING:
• The operator must be aware of safety precautions to prevent physical injury.
• Any pressure-containing device can explode, rupture, or discharge its contents if it is
over-pressurized. Take all necessary measures to avoid over-pressurization.
•Operating, installing, or maintaining the unit in any way that is not covered in this manual
could cause death, serious personal injury, or damage to the equipment. This includes
any modification to the equipment or use of parts not provided by Xylem. If there is a
question regarding the intended use of the equipment, please contact an Xylem
representative before proceeding.
•This manual clearly identifies accepted methods for disassembling units. These methods
must be adhered to. Trapped liquid can rapidly expand and result in a violent explosion
and injury. Never apply heat to impellers, propellers, or their retaining devices to aid in
their removal.
• Do not change the service application without the approval of an authorized Xylem
representative.
CAUTION:
You must observe the instructions contained in this manual. Failure to do so could result in
physical injury, damage, or delays.
User safety
General safety rules
These safety rules apply:
• Always keep the work area clean.
• Pay attention to the risks presented by gas and vapors in the work area.
•Avoid all electrical dangers. Pay attention to the risks of electric shock or arc flash
hazards.
• Always bear in mind the risk of drowning, electrical accidents, and burn injuries.
Safety equipment
Use safety equipment according to the company regulations. Use this safety equipment
within the work area:
• Hard hat
• Safety goggles, preferably with side shields
• Protective shoes
• Protective gloves
• Gas mask
• Hearing protection
Introduction and Safety
Flygt 2250 Installation, Operation, and Maintenance Manual 5

• First-aid kit
• Safety devices
NOTICE:
Never operate a unit unless safety devices are installed. Also see specific information
about safety devices in other chapters of this manual.
Electrical connections
Electrical connections must be made by certified electricians in compliance with all
international, national, state, and local regulations. For more information about
requirements, see sections dealing specifically with electrical connections.
Hazardous liquids
The product is designed for use in liquids that can be hazardous to your health. Observe
these rules when you work with the product:
• Make sure that all personnel who work with biologically hazardous liquids are
vaccinated against diseases to which they may be exposed.
• Observe strict personal cleanliness.
Wash the skin and eyes
Follow these procedures for chemicals or hazardous fluids that have come into contact
with your eyes or your skin:
Condition Action
Chemicals or hazardous
fluids in eyes 1. Hold your eyelids apart forcibly with your fingers.
2. Rinse the eyes with eyewash or running water for at least 15 minutes.
3. Seek medical attention.
Chemicals or hazardous
fluids on skin 1. Remove contaminated clothing.
2. Wash the skin with soap and water for at least 1 minute.
3. Seek medical attention, if necessary.
Environmental safety
The work area
Always keep the station clean to avoid and/or discover emissions.
Waste and emissions regulations
Observe these safety regulations regarding waste and emissions:
• Appropriately dispose of all waste.
• Handle and dispose of the processed liquid in compliance with applicable
environmental regulations.
• Clean up all spills in accordance with safety and environmental procedures.
• Report all environmental emissions to the appropriate authorities.
WARNING:
Do NOT send the product to the Xylem manufacturer if it has been contaminated by any
nuclear radiation. Inform Xylem so that accurate actions can take place.
Electrical installation
For electrical installation recycling requirements, consult your local electric utility.
Introduction and Safety
6 Flygt 2250 Installation, Operation, and Maintenance Manual

Transportation and Storage
Inspect the delivery
Inspect the package
1. Inspect the package for damaged or missing items upon delivery.
2. Note any damaged or missing items on the receipt and freight bill.
3. File a claim with the shipping company if anything is out of order.
If the product has been picked up at a distributor, make a claim directly to the
distributor.
Inspect the unit
1. Remove packing materials from the product.
Dispose of all packing materials in accordance with local regulations.
2. Inspect the product to determine if any parts have been damaged or are missing.
3. If applicable, unfasten the product by removing any screws, bolts, or straps.
For your personal safety, be careful when you handle nails and straps.
4. Contact your sales representative if anything is out of order.
Transportation guidelines
Precautions
WARNING:
• Stay clear of suspended loads.
• Observe accident prevention regulations in force.
Position and fastening
The unit can only be transported vertically. Make sure that the unit is securely fastened
during transportation, and cannot roll or fall over.
Lifting
WARNING:
• Crush hazard. The unit and the components can be heavy. Use proper lifting methods
and wear steel-toed shoes at all times.
• Lift and handle the product carefully, using suitable lifting equipment.
• The product must be securely harnessed for lifting and handling. Use eyebolts or lifting
lugs if available.
• Always lift the unit by its lifting handle. Never lift the unit by the motor cable or by the
hose.
• Do not attach sling ropes to shaft ends.
Temperature ranges for transportation, handling and storage
Handling at freezing temperature
At temperatures below freezing, the product and all installation equipment, including the
lifting gear, must be handled with extreme care.
Transportation and Storage
Flygt 2250 Installation, Operation, and Maintenance Manual 7

Make sure that the product is warmed up to a temperature above the freezing point before
starting up. Avoid rotating the impeller/propeller by hand at temperatures below the
freezing point. The recommended method to warm the unit up is to submerge it in the
liquid which will be pumped or mixed.
NOTICE:
Never use a naked flame to thaw the unit.
Unit in as-delivered condition
If the unit is still in the condition in which it left the factory - all packing materials are
undisturbed - then the acceptable temperature range during transportation, handling and
storage is: –50°C (–58ºF) to +60°C (+140ºF).
If the unit has been exposed to freezing temperatures, then allow it to reach the ambient
temperature of the sump before operating.
Lifting the unit out of liquid
The unit is normally protected from freezing while operating or immersed in liquid, but the
impeller/propeller and the shaft seal may freeze if the unit is lifted out of the liquid into a
surrounding temperature below freezing.
Units equipped with an internal cooling system are filled with a mixture of water and 30%
glycol. This mixture remains a flowing liquid at temperatures down to –13°C (9°F). Below –
13°C (9°F), the viscosity increases such that the glycol mixture will lose its flow properties.
However, the glycol-water mixture will not solidify completely and thus cannot harm the
product.
Follow these guidelines to avoid freezing damage:
1. Empty all pumped liquid, if applicable.
2. Check all liquids used for lubrication or cooling, both oil and water-glycol mixtures, for
the presence of water. Change if needed.
Storage guidelines
Storage location
The product must be stored in a covered and dry location free from heat, dirt, and
vibrations.
NOTICE:
• Protect the product against humidity, heat sources, and mechanical damage.
• Do not place heavy weights on the packed product.
Long-term storage
If the unit is stored more than 6 months, the following apply:
• Before operating the unit after storage, it must be inspected with special attention to
the seals and the cable entry.
• The impeller/propeller must be rotated every other month to prevent the seals from
sticking together.
Transportation and Storage
8 Flygt 2250 Installation, Operation, and Maintenance Manual

Product Description
Products included
Pump model Approvals
2250.011 Standard
Pump design
The pump is submersible, and driven by an electric motor.
Intended use
The product is intended for moving waste water, sludge, raw and clean water. Always
follow the limits given in Application limits (page 36). If there is a question regarding the
intended use of the equipment, please contact an Xylem representative before
proceeding.
WARNING:
In explosive or flammable environments, only use Ex- or MSHA-approved pumps.
NOTICE:
Do NOT use the pump in highly corrosive liquids.
For information about pH, see Application limits (page 36).
Particle size
The pump can handle liquid containing particles that correspond to the holes in the
strainer.
Number of holes Hole dimensions
508 15×45 mm (0.6×1.77 in.)
Pressure class
MT Medium head
HT High head
Impeller type
B Wear resistant
Poly-Life®
The pump is available with Poly-Life®polyurethane wear parts for extra resistance.
Monitoring equipment
The following applies to the monitoring equipment of the pump:
• The stator incorporates thermal contacts connected in series that activate the alarm at
overtemperature.
• The thermal contacts open at 125°C (257°F) and close at 95°C (203°F)
Product Description
Flygt 2250 Installation, Operation, and Maintenance Manual 9

The data plate
The data plate is a metal label located on the main body of the products. The data plate
lists key product specifications. Specially approved products also have an approval plate.
2
1312 14
22
21
20
17 18 1916159 10 11
8
7
6
5
4
31
23
24
WS006257A
1. Curve code/Propeller code
2. Serial number, see Product denomination (page 10)
3. Product number
4. Country of origin
5. Additional information
6. Phase; type of current; frequency
7. Rated voltage
8. Thermal protection
9. Thermal class
10. Rated shaft power
11. International standard
12. Degree of protection
13. Rated current
14. Rated speed
15. Maximum submergence
16. Direction of rotation: L=left, R=right
17. Duty class
18. Duty factor
19. Product weight
20. Locked rotor code letter
21. Power factor
22. Maximum ambient temperature
23. Read installation manual
24. Notified body. Only for EN-approved Ex-products
Figure 1: The data plate
Product denomination
Sales denomination
The sales denomination consists of the four-digit sales code and two letters that indicate
the hydraulic end and type of installation.
This is an example of a sales denomination, and an explanation of its parts.
1
NP 3085
2 3
WS006265A
1. Hydraulic part
2. Installation type
3. Sales code
Product Description
10 Flygt 2250 Installation, Operation, and Maintenance Manual

Product code
The product code consists of nine characters divided into two parts.
This is an example of a product code, and an explanation of its parts.
3085.183
1 2
NP
WS006262A
1. Sales denomination
2. Version
Serial number
The serial number is used for identification of an individual product, and is divided into
four parts.
This is an example of a serial number, and an explanation of its parts.
1
NP 3085.183 - 951 0163
2 3 4
WS006269A
1. Product code
2. Production year
3. Production cycle
4. Running number
Product Description
Flygt 2250 Installation, Operation, and Maintenance Manual 11

Installation
Install the pump
WARNING:
• Electrical shock hazard. Check that the cable and cable entry have not been damaged
during transport before installing the pump.
• Make sure that the unit cannot roll or fall over and injure people or damage property.
•Do not install CSA-approved products in locations that are classified as hazardous in the
national electric code, ANSI/NFPA 70-2005.
• Do not install the starter equipment in an explosive zone unless it is explosion-proof
rated.
NOTICE:
• Never force piping to make a connection with a pump.
These requirements apply:
• Use the pump dimensional drawing in order to ensure proper installation.
• Provide a suitable barrier around the work area, for example, a guard rail.
• Check the explosion risk before you weld or use electric hand tools.
• Remove all debris from the inlet piping system before you install the pump.
• Always check the impeller rotation before lowering the pump into the pumped liquid.
Sedimentation prevention
In order to avoid sedimentation when the pumped liquid contains solid particles, the
velocity of the liquid in the discharge line must exceed a certain value. Choose applicable
minimum velocity from the table, and choose proper dimension of the discharge line
accordingly.
Mixture Minimum velocity, meter per second (feet per second)
Water + coarse gravel 4 (13)
Water + gravel 3.5 (11)
Water + sand, particle size <0.6 mm (0.024 in) 2.5 (8.2)
Water + sand, particle size <0.1 mm (0.004 in) 1.5 (4.9)
For more permanent installations with a heavily contaminated pumped liquid, a settling
pump-sump is recommended.
WS001380B
Figure 2: Settling pump-sump
Discharge line requirements
The discharge line can be run vertically or horizontally, but must be without sharp bends.
Installation
12 Flygt 2250 Installation, Operation, and Maintenance Manual

Proper horizontal and vertical installation Improper installation with a sharp
bend
WS001379A
WS001346A
Fasteners
WARNING:
• Only use fasteners of the proper size and material.
• Replace all corroded fasteners.
• Make sure that all fasteners are properly tightened and that there are no missing
fasteners.
Install with S-installation
In the S-installation, the pump is transportable and intended to operate either completely
or partially submerged in the pumped liquid. The pump is equipped with a connection for
hose or pipe.
These requirements and instructions only apply when the installation is made according to
the dimensional drawing.
1. Run the cable so that it has no sharp bends. Make sure that it is not pinched, and
cannot be sucked into the pump inlet.
2. Connect the discharge line.
3. Lower the pump into the sump.
4. Place the pump on the base and make sure it cannot fall over or sink.
Alternatively, the pump can be suspended with a lifting chain just above the sump
bottom. Make sure that the pump cannot rotate at startup or during operation.
5. Connect the motor cable and the starter and monitoring equipment according to the
separate instructions.
Make sure that the impeller rotation is correct. For more information, see Check the
impeller rotation (page 21).
Installation
Flygt 2250 Installation, Operation, and Maintenance Manual 13

Make the electrical connections
General precautions
Electrical Hazard:
•A certified electrician must supervise all electrical work. Comply with all local codes and
regulations.
• Before starting work on the unit, make sure that the unit and the control panel are
isolated from the power supply and cannot be energized. This applies to the control
circuit as well.
• Leakage into the electrical parts can cause damaged equipment or a blown fuse. Keep
the end of the motor cable above the liquid level.
• Make sure that all unused conductors are insulated.
• There is a risk of electrical shock or explosion if the electrical connections are not
correctly carried out or if there is fault or damage on the product.
WARNING:
Do not install the starter equipment in an explosive zone unless it is explosion-proof rated.
CAUTION:
If the pump is equipped with automatic level control and/or internal contactor, there is a
risk of sudden restart.
WS006209A
Requirements
These general requirements apply for electrical installation:
•The supply authority must be notified before installing the pump if it will be connected
to the public mains. When the pump is connected to the public power supply, it may
cause flickering of incandescent lamps when started.
•The mains voltage and frequency must agree with the specifications on the data plate.
If the pump can be connected to different voltages, then the connected voltage is
specified by a yellow sticker close to the cable entry.
• The fuses and circuit breakers must have the proper rating, and the pump overload
protection (motor protection breaker) must be connected and set to the rated current
according to the data plate and if applicable the cable chart. The starting current in
direct-on-line start can be up to six times higher than the rated current.
• The fuse rating and the cables must be in accordance with the local rules and
regulations.
• If intermittent operation is prescribed, then the pump must be provided with
monitoring equipment supporting such operation.
• The thermal contacts/thermistors must be in use.
Installation
14 Flygt 2250 Installation, Operation, and Maintenance Manual

Cables
These are the requirements to follow when you install cables:
• The cables must be in good condition, not have any sharp bends, and not be pinched.
• The sheathing must not be damaged and must not have indentations or be embossed
(with markings, etc.) at the cable entry.
• The cable entry seal sleeve and washers must conform to the outside diameter of the
cable.
• The minimum bending radius must not be below the accepted value.
•If using a cable which has been used before, a short piece must be peeled off when
refitting it so that the cable entry seal sleeve does not close around the cable at the
same point again. If the outer sheath of the cable is damaged, then replace the cable.
Contact an Xylem service shop.
• The voltage drop in long cables must be taken into account. The drive unit’s rated
voltage is the voltage measured at the cable connection point in the pump.
Earthing (Grounding)
Electrical Hazard:
• You must earth (ground) all electrical equipment. This applies to the pump equipment,
the driver, and any monitoring equipment. Test the earth (ground) lead to verify that it is
connected correctly.
• If the motor cable is jerked loose by mistake, the earth (ground) conductor should be the
last conductor to come loose from its terminal. Make sure that the earth (ground)
conductor is longer than the phase conductors. This applies to both ends of the motor
cable.
• Risk of electrical shock or burn. You must connect an additional earth- (ground-) fault
protection device to the earthed (grounded) connectors if persons are likely to come
into physical contact with the pump or pumped liquids.
Earth (ground) conductor length
The earth (ground) conductor must be 100 mm ( 4.0 in.) longer than the phase conductors
in the junction box of the unit.
Connect the motor cable to the pump
CAUTION:
Leakage into the electrical parts can cause damaged equipment or a blown fuse. Keep the
end of the motor cable above the liquid level.
Installation
Flygt 2250 Installation, Operation, and Maintenance Manual 15

94
16
117
85
94
98 23
24
23 19 22
20
21
66
31
110
136
WS001321A
Part Description
16 Cover
21 Nuts
31 Gland nut
Figure 3: Cable entry
1. Check the data plate to see which connections are required for the power supply:
• Y
• D
• Y serial
• Y parallel
• Y/D
2. Arrange the connections on the terminal board in accordance with the required power
supply.
Do not use links (jumper strips) with the Y/D start.
Do not use links (jumper strips) with the 9 stator leads tandem-coupling.
3. Connect the motor conductors (U1, V1, W1, and earth (ground)) to the terminal board.
4. Make sure that the pump is correctly connected to earth (ground).
5. Make sure that any thermal contacts incorporated in the pump are properly connected
to the terminal board.
6. Install the cover.
7. Fasten the nuts and the gland nut on the entrance flange so that the cable insertion
assembly bottoms out.
After you have connected the motor cable to the pump, connect the motor cable and the
control cable to the starter equipment.
Installation
16 Flygt 2250 Installation, Operation, and Maintenance Manual

WARNING:
Do not install the starter equipment in an explosive zone unless it is explosion-proof rated.
Three thermal contacts are incorporated in the stator. They are normally closed.
Thermal contacts must never be exposed to voltages higher than 250 V, breaking current
maximum 6 A at a power factor 0.6. It is recommended that the thermal contacts are
connected to 24 V over a separate fuse to protect any other automatic equipment.
Cable charts
Connection locations
WS001021B
L1 L2 L3 T3 T4T1 T2
15
13
14
42 31
7
10
5
9
8
6
11
12
17
16
24
22
23
19 20
21
18
1 Starter equipment and main leads (L1, L2, L3) 13 Coil
2 Earth (ground) 14 Transformer
3 Functional ground 15 Capacitor
4 Control leads (T1, T2, T3, T4) 16 Softstarter
5 Phase shifter 17 Level regulator
6 Diode 18 Contactor, start relay or thermal relay
7 Motor cable, minimum 20 m (66 ft.) 19 Thermal detector in stator
8 Screen 20 Thermal detector in main bearing
9 Pump 21 Jumper
10 Crimp connection 22 Terminal board, terminal plate
11 Crimp isolation 23 Leakage sensor
12 Motor protector 24 Stator leads (U1, U2, U5, U6, V1, V2, V5, V6,
W1, W2, W5, W6, Z1, Z5, Z6)
Installation
Flygt 2250 Installation, Operation, and Maintenance Manual 17

Color code standard
Code Description
BN Brown
BK Black
WH White
OG Orange
GN Green
GNYE Green-Yellow
RD Red
GY Grey
BU Blue
YE Yellow
Installation
18 Flygt 2250 Installation, Operation, and Maintenance Manual