⚡ LX WP400-I Spa Pump – 4HP Single Speed Jet Pump

Ultimate Single-Speed Power for Maximum Jet Performance

💧 Product Overview

The LX WP400-I is a robust 4.0HP single-speed massage pump engineered for powerful water circulation and jet operation in demanding hot tub applications. As the most powerful single-speed pump in the LX WP series, the WP400-I delivers exceptional jet performance for large spas and swim spas requiring maximum hydrotherapy power.

This high-performance pump operates at a constant 2900 RPM, providing relentless jet power whenever activated. With a substantial 2.94kW motor drawing 12 amps, the WP400-I is designed for spa systems where raw power is the priority, such as dedicated jet pumps in multi-pump configurations or swim spa jet systems requiring maximum water thrust.

Featuring 2-inch union connections and supplied with a 4-core plain cable, the WP400-I offers straightforward installation with compact dimensions of 415mm × 202mm × 197mm. Commonly found in Chinese-manufactured spas, Coasts spas, and select Jacuzzi models, this pump has established itself as the go-to choice for hot tub owners who demand the ultimate in jet performance.

✨ Key Features

✅ 4.0HP Single-Speed Motor – Maximum power output at 2.94kW for uncompromising jet performance

✅ High-Performance Design – 2900 RPM delivers consistent, powerful water flow through jets

✅ Robust Construction – Built for demanding spa applications requiring sustained high-power operation

✅ 2″ Union Connections – Standard 2-inch plumbing for compatibility with most spa systems

✅ 4-Core Cable Supplied – Pre-wired for straightforward electrical connection

✅ 40µF Capacitor – Properly sized for reliable motor starting and sustained operation

✅ Compact Dimensions – 415mm × 202mm × 197mm fits most equipment bays

✅ Massage Pump Design – Optimised specifically for powerful jet operation

✅ Proven Compatibility – Works with Chinese spas, Coasts spas, and Jacuzzi models

✅ Single-Speed Simplicity – Dedicated jet pump operation without speed switching complexity

🔧 Technical Specifications

Motor Specifications

Specification	Value
Power Reference	4.0 HP
Motor Output	2.94 kW
Speed Type	Single Speed
RPM	2900
Amperage	12.0 A
Capacitor	40 µF

Physical Dimensions

Specification	Value
Length	415 mm
Width	202 mm
Height	197 mm
Plumbing Size	2″

Connection Specifications

Specification	Value
Plumbing Connections	2-inch unions
Electrical Cable	4-core plain cable (supplied)
Speed Type	1 Speed
Pump Type	Massage Pump

🔌 Electrical Requirements

Electrical Specification	Requirement
Amperage	12.0 A
Capacitor Rating	40 µF
Cable Type	4-core plain cable (supplied)

⚠️ IMPORTANT ELECTRICAL SAFETY NOTICE:

All electrical work must be carried out by a qualified electrician in accordance with UK wiring regulations (BS 7671). Hot tub installations require RCD protection (30mA) for safety. Never attempt electrical connections yourself unless you are appropriately qualified.

⚠️ Higher amperage requirement – At 12A, ensure your electrical circuit and breaker are appropriately rated for this pump. A dedicated circuit may be required.

💡 Tip: As a single-speed pump, the WP400-I is typically used as a dedicated jet pump in multi-pump spa configurations, where a separate circulation pump handles filtration and heating duties.

🔗 Compatibility Guide

Plumbing Configuration

Component	Specification
Plumbing Size	2″
Connection Type	2-inch unions

Compatible Hot Tub Brands

The LX WP400-I is commonly found in and compatible with:

• ♨️ Chinese-manufactured hot tubs and swim spas
• ♨️ Coasts Spas (not the American “Coast Spas”)
• ♨️ Select Jacuzzi models

🛠️ Installation Requirements

Mounting Specifications

Requirement	Specification
Dimensions (L × W × H)	415mm × 202mm × 197mm
Base Surface	Solid, level, vibration-dampening
Ventilation	Ensure adequate clearance for motor cooling

Plumbing Connections

Connection	Size
Plumbing	2″ unions

Installation Notes

⚠️ Pump must be installed below water level (flooded suction) – This ensures proper priming and prevents air lock issues.

⚠️ Never run the pump dry – Dry running causes immediate seal damage and may destroy the pump. Always ensure water is present before starting.

⚠️ Ensure proper electrical bonding to earth – All metal components must be correctly earthed as per BS 7671 requirements.

⚠️ Single-speed operation – This pump runs at full power (2900 RPM) whenever activated. For systems requiring variable speed or low-speed circulation, a separate circulation pump is typically used.

⚠️ Higher amperage draw – At 12A, ensure your electrical circuit is appropriately rated and consider a dedicated circuit for this pump.

🔄 Maintenance Guide

Routine Maintenance Schedule

Task	Frequency	Notes
Check for water leaks	Monthly	Inspect around seal area and union connections
Inspect union connections	Monthly	Tighten if any looseness detected
Check motor vents	Quarterly	Ensure vents are clear of debris for proper cooling
Inspect mounting bolts	Quarterly	Tighten if loose to reduce vibration
Listen for unusual sounds	Monthly	Early detection of bearing or impeller issues
Check amperage draw	Annually	Should read approximately 12A under load

Warning Signs – When to Replace

Consider replacing your pump if you notice:

• 🔊 Unusual noises such as grinding, screeching, or humming
• 💧 Water leaking from the mechanical seal area
• ⚡ Motor repeatedly tripping the circuit breaker
• 💨 Significantly reduced water flow from jets
• 🌡️ Motor housing becoming excessively hot to touch
• ⏱️ Pump struggling to start or humming without turning

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🎯 Ideal Applications

Application	Suitability	Notes
♨️ Dedicated Jet Pump	✅ Excellent	Maximum power for powerful massage jets
♨️ Swim Spa Jet System	✅ Excellent	4HP handles demanding swim current applications
♨️ Large Multi-Jet Systems	✅ Excellent	High flow for extensive jet configurations
♨️ Booster Pump	✅ Excellent	Additional jet power in multi-pump setups
♨️ Combined Jet/Circ Pump	⚠️ Limited	Single-speed runs at full power; separate circ pump recommended

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❓ Frequently Asked Questions

Q: What horsepower is this pump?

A: The WP400-I is rated at 4.0HP with a 2.94kW motor output.

Q: Is this a single or dual speed pump?

A: This is a single-speed pump operating at 2900 RPM. For dual-speed operation, see the WP series (WP200-II, WP250-II, WP300-II).

Q: Will this pump fit my hot tub?

A: This pump has 2-inch plumbing connections and compact dimensions of 415mm × 202mm × 197mm. Check your existing pump’s connection size and available space for compatibility.

Q: What is the amperage draw?

A: The pump draws 12.0A at full operation. Ensure your electrical circuit is appropriately rated.

Q: What size are the plumbing connections?

A: 2-inch unions are used for both suction and discharge connections.

Q: What capacitor does this pump use?

A: The pump uses a 40µF capacitor.

Q: Which hot tub brands is this compatible with?

A: The WP400-I is compatible with Chinese-manufactured spas, Coasts spas (not the American “Coast Spas”), and some Jacuzzi models.

Q: Can I use this as my only pump?

A: As a single-speed pump, the WP400-I runs at full power whenever activated. Most spa systems use it as a dedicated jet pump alongside a separate circulation pump for heating and filtration. For combined jet and circulation needs, consider a dual-speed WP pump instead.

Q: How do I know if my pump needs replacing?

A: Common signs include unusual grinding or screeching noises, water leaking from the seal area, reduced jet flow, the motor tripping the breaker repeatedly, or the pump struggling to start.

🏆 Why Choose the LX WP400-I

✅ Maximum Power – 4.0HP / 2.94kW delivers the strongest jet performance in the LX range

✅ Consistent Performance – Single-speed design provides reliable, full-power operation

✅ Compact Design – 415mm × 202mm × 197mm fits standard equipment bays

✅ Ready to Install – Supplied with cable and 2″ union connections

✅ Proven Compatibility – Works with Chinese spas, Coasts spas, and Jacuzzi models

✅ Quality Construction – Built to withstand continuous high-power operation

✅ Simple Operation – No speed switching complexity; full power when needed

🤝 Why Buy from Parts4Tubs

✅ UK-Based Company – Local support from spa parts specialists who understand your needs

✅ Fast UK Delivery – Quick dispatch to get your hot tub back up and running promptly

✅ Expert Technical Advice – Knowledgeable team available to help with compatibility questions and installation guidance

✅ Competitive Pricing – Great value on genuine quality parts without compromising on reliability

✅ Full Warranty Support – Peace of mind with comprehensive warranty coverage

✅ Easy Returns – Hassle-free returns within 30 days if you’re not completely satisfied

✅ Replacement Parts Available – Seal kits, impellers, capacitors, and other spares in stock

✅ Real People, Real Help – Buy from a person, not just the internet. We’re here to help with your spa parts needs

💪 Summary

The LX WP400-I is a powerful 4.0HP single-speed massage pump delivering maximum jet performance for large hot tubs and swim spas. With its robust 2.94kW motor operating at 2900 RPM and drawing 12A, this pump provides uncompromising power for demanding jet applications. Featuring 2-inch union connections, compact 415mm × 202mm × 197mm dimensions, and a supplied 4-core cable, the WP400-I is designed for straightforward installation. Compatible with Chinese spas, Coasts spas, and select Jacuzzi models, the WP400-I is the ultimate choice for hot tub owners who demand maximum single-speed jet power.

The hot tub industry doesnt make it easy for you when you are trying to match up the size of the unions (the part that screws your pipe work onto the pumps) Below you can see the physical sizes of the collars, and how they relate to the actual union size you need. So a measurement of 2.5", edge to edge on the collar of the pump is actually a 1.5" union - confusing - absolutely! If you are not sure, give me a shout!

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.