🔩 LX Lingxiao 56WUA400-II (NF) Spa Pump – 4.0 HP 2-Speed 230V Baseless

Whisper-quiet 56 frame power engineered for Sundance, Jacuzzi, and Dimension One spas

💧 Product Overview

The LX Lingxiao 56WUA400-II (NF) is a high-performance 2-speed jet pump built for demanding hot tub and spa applications. Manufactured by Guangdong Lingxiao Pump Industry Co., Ltd. — one of the world’s largest dedicated spa pump manufacturers with over 40 years of experience — this pump delivers powerful hydrotherapy massage on high speed and quiet filtration/circulation on low speed.

Rated at 4.0 HP (2.5 HP continuous duty), this 56-frame pump operates at 230V/60Hz and draws 12.0 amps on high speed and 4.4 amps on low speed. The baseless (NF = No Feet) design is specifically engineered for bracket-mounted installations commonly found in Sundance, Jacuzzi, and Dimension One spas. It features 2-inch MBT connections with center suction and side discharge, and the wet end can be rotated in 90-degree increments to match your existing plumbing layout. Unions are included; pump cord is sold separately.

This pump serves as a direct OEM replacement for Sundance/Jacuzzi part number 6500-367 and is also a popular aftermarket replacement for Waterway Executive, Aqua-Flo XP2e, and numerous other 56-frame spa pumps.

⭐ Key Features

• ✅ 4.0 HP / 2.5 HP Continuous – High-output motor delivers powerful jet massage on high speed with energy-efficient low-speed filtration
• ✅ 2-Speed Operation (3450/1725 RPM) – High speed for hydrotherapy massage, low speed for filtration and circulation
• ✅ 56 Frame Thru-Bolt Motor – Larger frame runs cooler and quieter than 48-frame pumps, extending motor lifespan
• ✅ 230V / 60Hz, 12.0/4.4A – North American electrical standard with robust amperage for consistent performance
• ✅ Baseless/Bracketless (NF) Design – Specifically engineered for bracket-mounted installations in Sundance, Jacuzzi, and Dimension One spas
• ✅ 2″ MBT Connections – Center suction with side discharge; thread OD measures approximately 3 to 3-1/16 inches across the pump threads
• ✅ Rotatable Wet End – Rotate in 90-degree increments to match your existing plumbing layout without modifications
• ✅ Pure Copper Winding Motor – Premium copper windings ensure efficient operation and extended service life
• ✅ Anti-Creep Bearings – High-temperature grease-filled bearings for quieter, longer-lasting operation
• ✅ Texas Instruments Thermal Protector – Automatic motor protection prevents overheating damage
• ✅ UL, CUL, ETL Certified – Fully certified for safety compliance in the United States and Canada
• ✅ 1-Year Manufacturer Warranty – Direct warranty coverage from Guangdong Lingxiao

🔩 Technical specifications

⚠️ Horsepower Rating Note: This pump is labeled as both 2.5 HP and 4.0 HP across different sources. The 2.5 HP rating represents continuous duty horsepower, while 4.0 HP represents brake horsepower. When comparing pumps, use the amperage draw (12.0A high / 4.4A low) as the most reliable comparison metric, as HP rating methods vary between manufacturers.

🔌 Electrical Requirements

Wiring Terminals (2-Speed):

💡 Wiring Verification Tip: When the pump powers up, it should start on low speed first. If it starts on high speed, power down immediately and reverse the Red and Black wires. Running on incorrect wiring can cause overheating and damage to the spa system.

💡 Single-Speed Operation: This pump can also be wired as a single-speed pump by connecting only the high-speed terminal and leaving the low-speed terminal unconnected. Use a 3-wire single-speed pump cord instead of a 4-wire 2-speed pump cord.

⚠️ IMPORTANT: All electrical work must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and local building codes. Hot tubs require GFCI (Ground Fault Circuit Interrupter) protection. A dedicated circuit is required – do not share with other appliances.

🔗 Compatibility Guide

This Pump:

• 📍 Frame: 56 Frame Thru-Bolt (Baseless/NF)
• 📍 Wet End: 2 inch MBT
• 📍 Discharge: 2 inch Side Discharge (rotatable)
• 📍 Suction: 2 inch Center
• 📍 Mounting: Bracket required (Part No. 6000-535 sold separately)

Direct Replacement For:

Sundance / Jacuzzi OEM Part Numbers:

• 6500-367, 6500-367S
• 6500-352
• 6500-363
• 6500-365
• 6500-343, 6500-343S
• 6500-128 (older model)
• 6500-261 (older model)
• 6500-761 (older model)
• 6500-359
• 6500-902 (TheraMax II)
• SD6500363, SD6500-363

Also Replaces:

Waterway:

• 3721621-1D
• 3721621-1W
• 3721623-1W8C (Waterway EX2, Morgan Spa)
• Energy Saver 430-0052

Aqua-Flo (Gecko Alliance):

• XP2e 4HP 56 Frame pumps
• 06130395-2040
• 06130310

Balboa / Vico:

• 1-00-0145
• 1-00-0146
• 1-00-0153

Dimension One:

• Used on D1 Reflections and Bay series (Mid 2023+)

Extensive Alternate / Cross-Reference Part Numbers:

Category	Part Numbers
LX / Lingxiao	56WUA400-II, 56WUA400-II(NF), 56WUA400-II-BL, WUA400-II, 10-56WUA400, 10-56WUA400-NF2, LX56WUA400II, 56WUA400-2/6
HydroMaster	BX4117-S2
Watkins	1431601-03 rev A, 77408
Industry / Distributor	PUM6BHP, PUM22901106, PUM6BHP-56F2S240V, PUM22000558, SPR1900, PRC9089X, 34-343-3045
Motor Numbers	T55MWBLJ-962, T55MWCNT-1432, T55CXBSR, 5KCP49UN9096X
Artesian Spa	05334001-2, 05334000-5, 05334026-2, 05334012-2040, 05330002-2, 05330883-2, 05330883-1, 05325004-5
Artesian Spa (05825)	05825001-2, 05825015-7, 05825489-2, 05825685-2
Artesian Spa (05834)	05834005-2, 05834006-2, 05834009-2, 05834014-2, 05834021-2, 05834030-5
Artesian Spa (05230)	05230366-2
Artesian Spa (05830)	05830685-2
Other OEM (078xx)	078306-1340, 07826787-2041, 07827778-2341, 07827743-2, 07827343-2, 7827774-2, 07726008-5
Other OEM (0783x)	07830306-2, 07830332-2, 07830001-1, 07830000-2, 07830707-2
Other OEM (071xx/073xx)	07127783-2, 07327783-2
Other OEM (066xx)	06625787-2, 06630485-2, 06630309-2
Other OEM	0800-390000, 05225427-2 (TheraMax II)

⚠️ Important: The 56WUA400-II (NF) is the baseless/bracketless version. If your existing pump has feet/base welded to the bottom, you need the footed version: 56WUA400-II (with feet). The NF version requires a mounting bracket (Part No. 6000-535, sold separately).

⚠️ Note: This pump’s wet end is NOT interchangeable with Waterway or Aqua-Flo wet ends. The complete pump is a direct replacement, but individual wet-end components are specific to the LX WUA platform.

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🛠️ Installation Requirements

Mounting:

Requirement	Specification
Mounting Position	Horizontal only
Mounting Type	Bracket-mounted (no base/feet)
Bracket Part Number	6000-535 (sold separately)
Ventilation	Adequate airflow clearance around motor for cooling
Access	Sufficient space for maintenance and motor capacitor(s)

Plumbing:

Connection	Size
Suction	2 inch MBT (center)
Discharge	2 inch MBT (side – rotatable)
Union Type	2 inch unions included
Thread OD	~3″ to 3-1/16″ (connects to 2″ ID flex hose/pipe)

What’s Included:

• 1x 56WUA400-II (NF) Spa Pump
• 1x Instruction Manual
• 1x Wiring Diagram
• 2x 2-inch Unions

NOT Included:

• Pump cord (reuse existing or purchase separately; for AMP-style 2-speed connector, see Part No. 16-2036)
• Mounting bracket (Part No. 6000-535)
• Union O-rings (Part No. 6000-645, if needed)

Installation Notes:

⚠️ Pump must be installed below water level (flooded suction) for proper operation ⚠️ Never run pump dry – causes immediate seal and bearing damage ⚠️ Ensure proper grounding and bonding per NEC requirements ⚠️ GFCI protection is required by code for all spa installations ⚠️ Motor posts are clearly labeled for correct wiring – refer to the pump label diagram ⚠️ Verify wet end orientation before final tightening – rotate wet end in 90-degree increments to align with plumbing ⚠️ Ensure sufficient space around motor for capacitor(s) – motor may have single or dual capacitors mounted on the housing

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🔧 Maintenance Guide

Routine Maintenance:

Task	Frequency	Notes
Check for leaks	Monthly	Around seal plate and union connections
Inspect unions and O-rings	Monthly	Tighten if needed; replace O-rings if cracked
Clean strainer/filter	As needed	Remove debris to maintain flow
Check amperage draw	Annually	Should match rated 12.0A high / 4.4A low
Inspect motor vents	Quarterly	Keep clear of debris for proper cooling
Check mounting bracket	Quarterly	Tighten bracket bolts if loose
Inspect drain plugs	Quarterly	Ensure tight at 3, 6, or 9 o’clock positions

Warning Signs – Replace Pump If:

• Unusual noise (grinding, screeching, or loud humming)
• Water leaking from the mechanical seal
• Motor trips circuit breaker repeatedly
• Noticeably reduced water flow or jet pressure
• Motor overheating or burning smell
• Excessive vibration during operation

Seal Information:

• 📍 Seal Type: Mechanical seal (Viton / Silicon Carbide / Graphite components)
• ⚠️ Replace seal at first sign of leakage
• ⚠️ Never run pump dry – dry operation destroys the mechanical seal within seconds

🎛️ Ideal Applications

Application	Suitability	Notes
♨️ Hot tub jet pump (primary)	Yes	Ideal for high-power hydrotherapy jets
♨️ Spa filtration (low speed)	Yes	Low speed provides energy-efficient filtration and circulation
♨️ Sundance / Jacuzzi spas	Yes	Direct OEM replacement for 6500-367 and related models
♨️ Dimension One spas	Yes	Used on D1 Reflections and Bay series (Mid 2023+)
🛁 Whirlpool bath	No	Oversized for standard whirlpool applications

❓ Frequently Asked Questions

Q: What horsepower is this pump? A: This pump is rated at 4.0 HP (brake horsepower) and 2.5 HP (continuous duty). The different ratings reflect different measurement standards used across the industry. For accurate comparison with other pumps, use the amperage draw: 12.0A on high speed and 4.4A on low speed at 230V.

Q: Will this fit my Sundance or Jacuzzi spa? A: This pump is a direct replacement for Sundance/Jacuzzi part numbers 6500-367, 6500-352, 6500-363, 6500-365, and related models. It is the baseless (NF) version designed for bracket-mounted installations. Verify your existing pump is baseless before ordering.

Q: What is the difference between the NF and footed version? A: The “NF” (No Feet) version has no base welded to the bottom of the motor and requires a mounting bracket (Part No. 6000-535, sold separately). The standard 56WUA400-II has feet/base welded on for floor mounting. Always match your replacement to the same mounting style as your existing pump.

Q: What voltage does this pump require? A: 230V / 60Hz. All electrical installation must be performed by a licensed electrician. Using incorrect voltage will damage the motor and void the warranty.

Q: Does this pump come with a cord? A: No, the pump cord is NOT included. You can reuse the cord from your existing pump, or purchase a new 4-wire AMP-style 2-speed pump cord (Part No. 16-2036 for a 72-inch cord).

Q: Does this pump come with unions? A: Yes, two 2-inch unions are included. Union O-rings (Part No. 6000-645) may need to be purchased separately depending on your installation.

Q: Can I use this as a single-speed pump? A: Yes. Connect only the high-speed terminal and leave the low-speed terminal unconnected, then use a 3-wire single-speed pump cord instead of a 4-wire 2-speed cord.

Q: What size are the ports? A: Both suction and discharge are 2-inch MBT (Male Buttress Thread). The thread OD measures approximately 3 to 3-1/16 inches across the pump threads, connecting to standard 2-inch ID flex hose or pipe.

Q: Can I rotate the discharge direction? A: Yes. The wet end can be rotated in 90-degree increments to match your existing plumbing layout. The pump ships with discharge in the 12 o’clock (top) position by default.

Q: Does this pump replace the Waterway Executive? A: Yes, this pump is a popular aftermarket replacement for Waterway Executive 56-frame 4HP pumps (Part No. 3721621-1D, 3721621-1W). Note that some plumbing adjustments may be necessary due to slightly different thread positions.

Q: Does this pump replace the Aqua-Flo XP2e? A: Yes, this pump commonly replaces the Aqua-Flo XP2e 4.0 HP 56-frame pump and Energy Saver 430-0052. However, the LX wet end is not interchangeable with Aqua-Flo wet ends; this is a complete pump replacement.

Q: Do I need a mounting bracket? A: If your existing pump uses a bracket (baseless/NF configuration), you can reuse your existing bracket. If you need a new bracket, the part number is 6000-535 (sold separately).

Q: What warranty is included? A: 1-year warranty directly through the manufacturer, Guangdong Lingxiao Pump Industry Co., Ltd. Contact Parts4Tubs for warranty support.

Q: Do I need a GFCI breaker? A: Yes, GFCI protection is required by the National Electrical Code (NEC) for all hot tub and spa installations.

🏆 Why Choose the LX 56WUA400-II (NF)

• ✅ Powerful Performance – 4.0 HP brake horsepower with dual-speed operation for both massage and filtration
• ✅ Superior Build Quality – Pure copper motor windings, anti-creep bearings, and 80,000-cycle tested capacitors for long-lasting reliability
• ✅ Quieter Operation – 56-frame motor runs cooler and quieter than comparable 48-frame pumps
• ✅ Versatile Installation – Rotatable wet end with 90-degree increments eliminates plumbing modifications
• ✅ Broad Compatibility – Direct replacement for 50+ OEM part numbers across Sundance, Jacuzzi, Dimension One, Waterway, and Aqua-Flo platforms
• ✅ Certified Safety – UL, CUL, and ETL certified with integrated thermal protection

🤝 Why Buy from Parts4Tubs

• ✅ US-based support for American customers
• ✅ Fast shipping across the United States
• ✅ Expert advice from spa and hot tub specialists
• ✅ Competitive pricing in USD
• ✅ Full warranty support
• ✅ Hassle-free returns
• ✅ Replacement seals, brackets, and accessories available
• ✅ Dedicated customer service team

✨ Summary

The LX Lingxiao 56WUA400-II (NF) is a powerful, reliable 2-speed spa jet pump rated at 4.0 HP / 2.5 HP continuous, operating at 230V/60Hz with 12.0/4.4A draw. Featuring a 56-frame thru-bolt motor in a baseless design for bracket-mounted installations, this pump offers 2-inch MBT connections with a rotatable wet end, UL/CUL/ETL certification, pure copper windings, and anti-creep bearings. A direct OEM replacement for Sundance/Jacuzzi 6500-367 and compatible with 50+ cross-reference part numbers. Order today from Parts4Tubs for fast US shipping and expert support.

Find the right pump or motor

Enter what is printed on the label of the one you are replacing. Anything that differs is shown with the difference spelled out, so you can judge it for yourself.

EitherComplete pumpMotor only

Make or modelHorsepowerVoltageAny115V230VSpeedAny1-speed2-speedVariable speedAmpsPort size (pumps)Any3/4 in1 in1-1/2 in2 in2-1/2 inFrame (motors)Any48Y48 frame56Y56J56C56 frame

Clear

Port size is the plumbing thread, not the pipe — a 2 inch union measures about 3 inches across the male thread. Amps are compared to within half an amp, since published figures round differently between motor brands. Voltage is never treated as a near miss: a 115V motor is not one step from a 230V supply. Anything whose page does not publish a figure you entered is left out rather than offered with a caveat — search it by name to see it anyway.

Unions and pump cords: pick the union size that matches your pump's ports (see the size chart below), and a 4-wire cord for a 2-speed pump.

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	Magic Plastics Union 0602-15 (1.5″ Pump Union) | 1-1/2″S x 1-1/2″FBT Union, Pump, Magic, 1-1/2"S x 1-1/2"FBT (Industry Standard) w/ O-Ring Manufacturer part number 0602-15B Returns 30-day returns – see our returns policy	$6.36 Max: 241 Min: 1 Step: 1 Add to cart
	Magic Plastics Union 0602-20 (2″ Pump Union) | 2″S x 2″FBT w/ O-Ring Union, Pump, Magic, 2"S x 2"FBT (Industry Standard) w/ O-Ring Manufacturer part number 0602-20 Returns 30-day returns – see our returns policy	$8.00 Max: 406 Min: 1 Step: 1 Add to cart
	Waterway Union 400-6010 | 2-1/2″ Union Nut with 2-1/2″ Slip tailpiece and o-ring (2.5″ union) Union, Pump, Waterway, 2-1/2"FBT x 2-1/2"S Manufacturer part number 400-6010 UPC (GTIN) 806105082176 Returns 30-day returns – see our returns policy	$14.77 Max: 81 Min: 1 Step: 1 Add to cart
	1 Speed Pump / Blower / AMP Cord | 21086 Amp Plug, Pump, 1-Speed, 14/3, 4-Pin, 5' Cord, White Manufacturer part number 21086 Returns 30-day returns – see our returns policy	$24.71 Max: 317 Min: 1 Step: 1 Add to cart
	Balboa Amp Plug 21087 (For 2 Speed Pumps) Amp Plug, Pump 1 (2-Speed) 14/4, 72" Long, White Manufacturer part number 21087 Returns 30-day returns – see our returns policy	$31.72 Max: 416 Min: 1 Step: 1 Add to cart

Hot Tub Pump Collar & Union Size Chart

Imperial & Metric Specifications

Union Size	Collar Size	Thread OD	Union OD	O-Ring Size
1.5" Female Buttress Thread (FBT)	2.5" / 64mm (Tip to Tip) Measurement	2-1/2" 64mm	2-13/16" 71mm	2-5/16" OD 59mm
2" Female Buttress Thread (FBT)	3.1" / 78mm (Tip to Tip) Measurement	3-1/16" 78mm	3-3/8" 81mm	2-15/16" OD 75mm
2.5" Female Buttress Thread (FBT)	3.6" / 91mm (Tip to Tip) Measurement	3-5/8" 91mm	4-1/4" 108mm	3-7/16" OD 87mm

Important Notes

The union "size" (1.5", 2", 2.5") is nominal and doesn't correspond to any actual measurement.

Collar size is measured from thread tip to thread tip on the pump outlet.

Most hot tub pumps use Female Buttress Thread (FBT) - 98% of applications.

O-ring gaskets may vary between manufacturers - measure your existing gasket for accuracy.

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
• Screwdriver
• New union O-rings
• A strap wrench, only if a union nut is stuck
• PVC primer and cement, only if you are gluing in new tailpieces

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. Unscrew the union nuts by hand. If one is stuck, use a strap wrench rather than a pipe wrench, which can crack the nut. 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. Pump unions use buttress threads that seal on an O-ring, so fit new O-rings and hand-tighten the nuts. Do not use thread tape, pipe dope or sealant on them.

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, hand-tightening the union nuts. If you are gluing in new PVC tailpieces, use PVC primer and cement on those joints.

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.