🛁 Little Giant 1-AA-18 Oil-Filled Submersible Pump – 1/200 HP, 170 GPH, 18-Ft Cord

Rugged die-cast aluminum construction with extended-reach 18-foot cord for pool covers, fountains, and water transfer

♨️ Product Overview

The Little Giant 1-AA-18 (Part No. 500500) is a compact, oil-filled submersible pump from the 1-A Series manufactured by Little Giant, a division of Franklin Electric. This rugged 1/200 HP direct-drive pump delivers 170 gallons per hour at 1 foot of lift with a maximum shut-off head of 7 feet, making it a versatile workhorse for pool cover drainage, statuary fountains, water displays, air conditioner condensate removal, machine tool coolant recirculation, and general water transfer applications.

What sets the 1-AA-18 apart from the standard 1-A model is its extended 18-foot power cord, providing the extra reach needed for pool cover pumping and larger water feature installations without requiring extension cords. The pump features an epoxy-coated die-cast aluminum housing and cover that provide superior durability and corrosion resistance compared to plastic-bodied pumps. The oil-filled motor housing uses a dielectric lubricant for optimal heat transfer and lifetime lubrication of the internal bearings, enabling continuous-duty operation.

With a 1/4-inch MNPT threaded discharge that easily adapts to 1/2-inch tubing or garden hose connections, impedance protection against motor overheating, and a screened bottom intake to prevent debris ingestion, the 1-AA-18 is built for reliable service across commercial, industrial, and residential applications. The pump draws just 1.1 amps at 70 watts, handles liquid temperatures up to 120°F, and weighs only 4.17 pounds. CSA listed in the USA and Canada, with a 1-year manufacturer warranty.

✨ Key Features

✅ Oil-Filled Direct-Drive Motor – Dielectric lubricant provides optimal heat transfer and permanently lubricated bearings for reliable continuous-duty operation

✅ 170 GPH at 1-Foot Lift – Steady flow rate handles pool cover drainage, medium fountain displays, and water transfer applications with 7-foot maximum shut-off head

✅ Epoxy-Coated Die-Cast Aluminum Housing – Rugged metal construction resists corrosion and physical damage far better than plastic-bodied pumps

✅ Extended 18-Foot Power Cord – Extra-long cord reaches across pool covers and large water features without extension cords

✅ 1/4″ MNPT Threaded Discharge – Standard pipe thread connection easily adapts to 1/2-inch tubing or garden hose fittings

✅ Impedance Protected Motor – Built-in protection guards against motor overheating from locked-rotor or stall conditions

✅ Screened Bottom Intake – Snap-off screen prevents debris from entering the impeller and allows easy cleaning access

✅ Polypropylene Wet End Components – Corrosion-resistant volute, screen, elbow, and impeller stand up to extended submersed operation

✅ Nitrile Shaft Seal – Chemical-resistant seal material provides reliable protection against water intrusion into the motor housing

✅ 120°F Maximum Liquid Temperature – Handles warm water from pool covers, condensate, and other above-ambient applications

✅ Ultra-Compact and Lightweight – Measures just 4.25″ × 4.13″ and weighs only 4.17 pounds for easy placement and positioning

✅ CSA Listed – Certified for safety in the USA and Canada

🔩 Technical Specifications

Specification	Value
Manufacturer	Little Giant (Franklin Electric)
Model	1-AA-18
Part Number	500500
Series	1-A Series (Oil-Filled Submersible)
Pump Type	Submersible, Oil-Filled, Direct Drive
Horsepower	1/200 HP
Voltage	115V
Frequency	60 Hz
Phase	Single
Amperage	1.1 A
Wattage	70W
Flow Rate (at 1 ft)	170 GPH (2.83 GPM)
Flow Rate (at 3 ft)	140 GPH
Flow Rate (at 5 ft)	100 GPH
Shut-Off Head	7 ft (2.1 m)
Maximum Pressure	3.0 PSI
Maximum Liquid Temperature	120°F (49°C)
Discharge	1/4″ MNPT
Inlet	Screened bottom intake
Housing / Cover	Epoxy-Coated Die-Cast Aluminum
Volute / Elbow	Polypropylene
Screen	Polypropylene
Impeller	Polypropylene
Shaft Seal	Nitrile
Motor Housing	Oil-Filled (dielectric lubricant)
Motor Protection	Impedance Protected
Cord Length	18 ft
Dimensions (H × L)	4.25″ × 4.13″
Weight	4.17 lbs
Operation	Submersible Only, Continuous Duty
Speed	Single Speed
Certifications	CSA Listed (USA and Canada)
Warranty	1 Year

⚡ Electrical Requirements

Electrical Spec	Requirement
Supply Voltage	115V
Frequency	60 Hz
Phase	Single
Amperage	1.1 A
Wattage	70W
Cord Length	18 ft
Cord Type	3-prong grounded plug
Motor Protection	Impedance Protected

⚠️ IMPORTANT:

All electrical connections must comply with the National Electrical Code (NEC) and all applicable local building codes.

GFCI (Ground Fault Circuit Interrupter) protection is required for all outdoor and pool-area installations per NEC requirements.

The pump draws 1.1 amps (70 watts). It must be connected to a properly grounded outlet with GFCI protection. Do not use damaged or undersized extension cords. The 18-foot cord is designed to eliminate the need for extension cords in most pool cover and water feature applications.

📊 Performance Curve Data

Lift Height	Flow Rate (GPH)	Flow Rate (LPH)
1 ft	170	643
3 ft	140	530
5 ft	100	379
7 ft (shut-off)	0	0

💡 Performance Notes: The 1-AA-18 maintains strong flow rates even at higher lift heights — delivering 140 GPH at 3 feet and 100 GPH at 5 feet. This makes it effective for pool cover drainage where water must be lifted over the pool edge and for fountain features requiring moderate head pressure. Maximum pressure output is 3.0 PSI.

🔗 Compatibility Guide

This Pump:

📍 Discharge: 1/4″ MNPT (top discharge) 📍 Tubing Compatibility: Adapts to 1/2″ ID tubing or standard garden hose via adapter (adapter sold separately) 📍 Voltage: 115V / 60Hz only 📍 Operation: Submersible use only — must be fully submerged

Discharge Connection:

The 1/4-inch MNPT (Male National Pipe Thread) discharge accepts standard threaded fittings and adapters. For pool cover applications, a garden hose adapter allows connection to a standard garden hose to direct water away from the pool. For fountain and display applications, a barbed adapter allows connection to 1/2-inch ID flexible tubing. Both adapter types are available separately from Little Giant and third-party suppliers.

Complete 1-A Series Lineup:

Part Number	Model	Cord Length	Description
500203	1-A	6 ft	Standard cord length
500286	1-AT	10 ft	Medium cord length
500500	1-AA-18 (this pump)	18 ft	Extended cord length

All three models share identical pump performance (170 GPH, 1/200 HP, 7 ft shut-off) and differ only in cord length. Choose the model that best matches your installation distance requirements.

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🛠️ Installation Requirements

Submersible Installation:

Requirement	Specification
Positioning	Fully submerged in water
Orientation	Place with screen as base (screen down)
Discharge Direction	Top — route tubing or hose upward
Minimum Water Depth	Pump must be fully submerged during operation

Pool Cover Application:

Place the pump at the lowest point on the pool cover where water accumulates. Ensure the pump is fully submerged before plugging in. Connect the 1/4″ MNPT discharge to a garden hose adapter and route the hose away from the pool to a suitable drainage area. The 18-foot cord provides ample reach to a GFCI-protected outdoor outlet in most installations.

Fountain / Water Feature Application:

Position the pump at the bottom of the fountain basin or reservoir. Connect the discharge to 1/2″ ID tubing routed to the fountain head or ornament. Ensure the pump remains fully submerged during operation.

Installation Notes:

⚠️ This pump is designed exclusively for submersible use. Never operate above water level or allow the pump to run dry — this will damage the shaft seal and motor.

⚠️ Do not leave the pump outside in freezing temperatures. If using during winter, operate the pump only when needed and bring it indoors after water removal is completed.

⚠️ Keep the screened intake clean and free of debris. The snap-off screen allows easy removal for cleaning.

⚠️ For outdoor and pool-area installations, GFCI protection is required by the NEC.

⚠️ This pump is not recommended for aquariums, swimming pool circulation, or fuel oil transfer.

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🔧 Maintenance Guide

Routine Maintenance:

Task	Frequency	Notes
Clean inlet screen	Monthly (or as needed)	Snap off screen and rinse to clear debris
Inspect power cord	Monthly	Check for damage, cuts, or exposed wiring
Check discharge connection	Monthly	Ensure adapter and tubing are secure
Inspect pump exterior	Quarterly	Remove mineral deposits and algae buildup
Verify GFCI function	Monthly	Test GFCI reset button for outdoor installations
Clean impeller area	Every 6 months	Remove volute to check for debris or calcium buildup

Warning Signs — Service or Replace Pump If:

• Motor hums but does not pump water
• Noticeable reduction in flow rate despite clean intake screen
• Unusual noise (grinding, clicking, or rattling)
• Water leaking from the shaft seal area
• Power cord or plug shows visible damage
• Motor trips GFCI breaker repeatedly
• Oil residue visible in the water around the pump

Winterization / Storage:

For seasonal applications like pool cover pumping, remove the pump from the water after each use during cold weather. Drain the pump completely and store indoors in a dry location above freezing temperatures. Do not leave the pump submerged in water that may freeze, as ice expansion can crack the aluminum housing and damage internal seals.

Shaft Seal Information:

📍 Seal Type: Nitrile ⚠️ If oil appears in the water surrounding the pump, the shaft seal has failed and the pump should be removed from service and replaced. The oil-filled motor design means seal failure will result in oil leaking into the water.

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🎯 Ideal Applications

Application	Suitability	Notes
💧 Pool cover drainage	✅ Yes	Primary designed application; 18 ft cord ideal for reaching outlets
💧 Statuary fountains	✅ Yes	Steady 170 GPH with 7 ft maximum head
💧 Water displays	✅ Yes	Continuous duty with reliable oil-filled motor
💧 Air conditioner condensate	✅ Yes	Compact size fits in condensate pans and reservoirs
💧 Machine tool coolant	✅ Yes	Recirculates coolant in industrial machining applications
💧 Hydroponic systems	✅ Yes	Water transfer and recirculation for ebb-and-flow systems
💧 General water transfer	✅ Yes	Moves water between containers, tanks, or basins
💧 Water recirculation	✅ Yes	Continuous duty for closed-loop recirculating systems
♨️ Hot tub draining	⚠️ Limited	170 GPH is very slow for hot tub draining; max 120°F temp may be exceeded
♨️ Spa jet pump	❌ No	Not designed for pressurized jet applications
💧 Aquarium use	❌ No	Not recommended by manufacturer (oil-filled motor)
💧 Swimming pool circulation	❌ No	Not recommended by manufacturer
💧 Fuel oil transfer	❌ No	Not recommended by manufacturer

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❓ Frequently Asked Questions

Q: What horsepower is this pump? A: The 1-AA-18 is rated at 1/200 HP. Despite the small horsepower rating, it reliably delivers 170 GPH at 1-foot lift and maintains 100 GPH even at 5 feet of head pressure.

Q: What is the difference between the 1-A, 1-AT, and 1-AA-18? A: All three models are identical pumps with the same 1/200 HP motor, 170 GPH flow rate, and 7-foot shut-off head. The only difference is cord length: the 1-A (500203) has a 6-foot cord, the 1-AT (500286) has a 10-foot cord, and the 1-AA-18 (500500) has an 18-foot cord.

Q: Can I use this as a pool cover pump? A: Yes, pool cover drainage is one of the primary designed applications. Place the pump at the lowest point on the cover where water collects, connect a garden hose adapter to the discharge, and route the hose to a drainage area. The 18-foot cord provides ample reach to an outlet.

Q: Does the pump turn on and off automatically? A: No, the 1-AA-18 is a manual (non-automatic) pump. It runs continuously when plugged in and stops when unplugged. Little Giant offers automatic pool cover pumps with float switches for hands-free operation.

Q: What size tubing or hose connects to the discharge? A: The 1/4″ MNPT threaded discharge accepts standard pipe thread adapters. For garden hose connection, use a 1/4″ MNPT to 3/4″ garden hose thread adapter. For tubing, use a 1/4″ MNPT to barb adapter for 1/2″ ID flexible tubing.

Q: Can this pump handle hot water? A: The pump is rated for liquid temperatures up to 120°F (49°C). This covers most pool cover water, condensate, and warm water transfer applications, but may not be suitable for draining hot tubs at full operating temperature.

Q: Why is there oil in the water around my pump? A: Oil in the water indicates the nitrile shaft seal has failed, allowing the dielectric motor lubricant to leak out. Remove the pump from service immediately and replace it. Continued operation with a failed seal will damage the motor.

Q: Can I leave this pump outside in winter? A: No. Do not leave the pump outside in freezing temperatures. If using during winter for pool cover drainage, operate the pump only when needed and bring it indoors after use. Freezing water inside the pump can crack the aluminum housing.

Q: How much electricity does this pump use? A: The pump draws 1.1 amps (70 watts). Running continuously 24/7, it consumes about 1.68 kWh per day, or approximately 50 kWh per month. At a typical US electricity rate of $0.15/kWh, the cost is roughly $7.50 per month for continuous operation.

Q: What is impedance protection? A: Impedance protection is a motor design feature that prevents the motor from overheating if the impeller becomes locked or stalled. Unlike thermal overload protection that requires a reset, impedance-protected motors are designed to withstand a locked-rotor condition without damage.

Q: Do I need GFCI protection? A: Yes, for all outdoor and pool-area installations. GFCI protection is required by the National Electrical Code (NEC) for any electrical connection near water.

Q: How heavy is this pump? A: The 1-AA-18 weighs 4.17 pounds, making it easy to handle and position on pool covers or in fountain basins.

📥 Downloads & Resources

📄 1-A Series Spec Sheet – Complete specifications, performance curves, and dimensions for all 1-A Series models

📄 1 Series Installation Manual – Installation instructions, wiring, troubleshooting, and maintenance

⭐ Why Choose the Little Giant 1-AA-18

✅ Die-Cast Aluminum Durability – Epoxy-coated metal housing provides far superior impact resistance and longevity compared to all-plastic pump bodies

✅ Extended 18-Foot Cord – Reaches outlets from pool cover centers and large water features without extension cords, simplifying installation

✅ Reliable Oil-Filled Motor – Permanently lubricated bearings and dielectric oil cooling enable dependable continuous-duty operation

✅ Versatile Multi-Application Design – One pump handles pool covers, fountains, water displays, condensate removal, coolant recirculation, and water transfer

✅ Strong Performance at Height – Delivers 100 GPH even at 5 feet of lift, with 7-foot maximum shut-off head for demanding installations

✅ Impedance Protected – Motor withstands locked-rotor conditions without damage, preventing costly failures from debris jams

✅ 80+ Years of Little Giant Heritage – Backed by Franklin Electric’s extensive pump manufacturing expertise and nationwide support

✅ CSA Listed – Independently certified for safety in the USA and Canada

🤝 Why Buy From Parts4Tubs

✅ US-based support for American customers

✅ Fast shipping across the United States

✅ Expert advice from pool, spa, and water equipment specialists

✅ Competitive pricing in USD

✅ Full warranty support

✅ Hassle-free returns

✅ Complete 1-A Series lineup available

✅ Dedicated customer service team

💧 Summary

The Little Giant 1-AA-18 (500500) is a 1/200 HP oil-filled direct-drive submersible pump delivering 170 GPH at 1 foot of lift with a 7-foot shut-off head. This rugged pump features an epoxy-coated die-cast aluminum housing and cover, polypropylene volute and impeller, nitrile shaft seal, oil-filled motor with impedance protection, 1/4-inch MNPT discharge, screened bottom intake, and an extended 18-foot power cord. Drawing just 1.1 amps (70 watts), it handles liquid temperatures up to 120°F and weighs only 4.17 pounds. Ideal for pool cover drainage, statuary fountains, water displays, condensate removal, machine tool coolant, and general water transfer. CSA listed with a 1-year warranty. Order today from Parts4Tubs for fast US shipping and expert support.

How do I Replace a Hot Tub Pump?

Here's a general step-by-step guide on how to replace a hot tub pump. Keep in mind that the specific steps may vary depending on your hot tub's make and model, so it's essential to consult your hot tub's manual for model-specific instructions. If you're not comfortable with this procedure, it's a good idea to seek professional assistance.

Materials You'll Need:

• Replacement pump
• Pipe wrench
• Adjustable wrench
• Screwdriver
• Pipe sealant (thread tape or plumber's putty)
• PVC primer and cement (if you have PVC plumbing)
• Teflon tape (for threaded connections)

Procedure:

1. Turn Off the Power: Before you begin, ensure the hot tub's power supply is turned off at the circuit breaker or disconnect switch. Safety should always be a priority when working with electrical components.

2. Drain the Hot Tub: If your hot tub is not already empty, you'll need to drain it. Follow your hot tub's manual or manufacturer's instructions for proper draining. (You might not need to do this if you can lock the pump off with the gate valves)

3. Locate the Pump: Identify the location of the existing pump in your hot tub. It's usually located near the equipment area or in a designated pump compartment.

4. Disconnect the Electrical Wiring: Carefully disconnect the electrical wiring from the old pump. This typically involves removing the electrical conduit cover, unscrewing wire nuts, and disconnecting the wires from the terminals. Be sure to note the wire connections or take a picture for reference when connecting the new pump.

5. Disconnect the Plumbing: Depending on your hot tub's plumbing setup, you'll need to disconnect the plumbing connections to the pump. Use a pipe wrench or adjustable wrench to loosen and remove the fittings. Be prepared for some water spillage when disconnecting the plumbing.

6. Remove the Old Pump: Once the electrical and plumbing connections are detached, carefully remove the old pump from its mounting position. Some pumps may be secured with mounting brackets or bolts.

7. Prepare the New Pump: If the new pump is not pre-assembled, you may need to attach fittings, unions, or adapters to match your hot tub's plumbing. Ensure that you use the appropriate sealant or Teflon tape on threaded connections to prevent leaks.

8. Mount the New Pump: Position the new pump in the same location as the old one and secure it in place using the mounting brackets or bolts.

9. Reconnect Plumbing: Reconnect the plumbing to the new pump, ensuring that all connections are tight and secure. If your hot tub uses PVC plumbing, use PVC primer and cement to bond the connections properly.

10. Reconnect Electrical Wiring: Reconnect the electrical wiring to the new pump, following the notes or pictures you took earlier. Make sure all wires are properly connected and secure.

11. Turn On the Power: Restore power to the hot tub by switching on the circuit breaker or reconnecting the disconnect switch.

12. Test the Pump: Turn on the hot tub's pump to ensure that it's working correctly. Check for any signs of leaks or irregularities in the plumbing connections.

13. Refill the Hot Tub: Once you've confirmed that the new pump is functioning properly, refill the hot tub with water.

14. Check for Leaks: Inspect the plumbing connections for any leaks. If you find any, turn off the pump, drain the tub again, and reseal the connections as needed.

15. Monitor: Keep an eye on the pump and plumbing for the next few days to ensure everything is functioning correctly and that there are no further issues.

Remember that this is a general guideline, and the specific steps may vary based on your hot tub's design. If you're unsure or uncomfortable with any aspect of this process, please do get in touch, happy to help.

How do I know what size hot tub pump I have?

Determining the size of your hot tub pump is an important step when it comes to maintenance or replacement. To find out the size of your hot tub pump, follow these steps:

1. Check the Manual: The easiest way to determine the size of your hot tub pump is to consult the owner's manual or user documentation that came with your hot tub. The manual typically contains detailed information about the specifications and components of your hot tub, including the pump.

2. Look at the Pump Housing: If you don't have access to the manual or it doesn't provide the information you need, inspect the pump itself. Most hot tub pumps have a label or plate on the pump housing that displays essential details, including the pump's model number, manufacturer, and specifications. You can then send that to me or Google it.

3. Measure the Pump: If the label is missing or damaged, you can measure the pump's dimensions. Measure the diameter of the pump's wet end (the part where the water flows) and the length of the wet end. These measurements can help identify the size and capacity of the pump.

4. Consult the Manufacturer: If you can't find the information on the pump or in the manual, contact the hot tub manufacturer or a reputable dealer. Provide them with your hot tub's model and serial number, and they should be able to identify the correct pump size for your specific hot tub.

5. Online Research: You can also search online using the pump's model number or hot tub's make and model. Many manufacturers provide detailed information about their products on their websites, and you may find specifications for your pump model.

Once you have determined the size and specifications of your hot tub pump, you can proceed with maintenance, repairs, or replacement if necessary. Keep in mind that replacing a hot tub pump with the same size and capacity as the original is crucial to ensure proper water circulation and filtration in your hot tub. If you're unsure about any aspect of this process, get in touch, always happy to help.