⚙️ Waterway E-Series 0.75 HP Spa Pump (3420310-15) — Dual-Speed 115V 48 Frame Center Discharge Jet Pump with 1-1/2″ Connections

Compact, Versatile Center Discharge Performance — The Reliable Replacement for Most 48-Frame 1-1/2″ Center Discharge Spa Pump Applications

💧 Product Overview

The Waterway E-Series 3420310-15 is a 0.75 HP dual-speed center discharge jet pump manufactured by Waterway Plastics, a US-based company that has been a leader in the bath and spa industry since 1973. This compact 48-frame thru-bolt pump features a center discharge configuration — the suction port faces forward (center) and the discharge port exits from the top — distinguishing it from the side discharge layout found on larger spa pumps like the Waterway Executive or Hi-Flo series.

Operating on 115V/60Hz, this pump draws 8.8 amps on high speed (3450 RPM) and 2.6 amps on low speed (1725 RPM), making it ideal for smaller and mid-size hot tubs, whirlpool baths, and entry-level spa systems that run on standard 115V household circuits. The 1-1/2″ MBT (Male Buttress Thread) connections on both intake and discharge (approximately 2-7/16″ across threads) connect to standard 1-1/2″ ID plumbing.

The E-Series is the current-production replacement for the older Waterway center discharge pump line. The easiest way to identify this newer design is the 6-screw faceplate on the wet end (the older discontinued model had a 4-screw faceplate). The wet end can be rotated to match existing plumbing. The pump features silicon carbide seals with Viton bellows and a 316 stainless steel seal casing for chemical resistance and durability.

This pump includes two 400-4060 pump unions that accept 1-1/2″ PVC pipe. Power cord is NOT included — reuse your existing pump cord or purchase a compatible replacement. California Title 20 Compliant. Backed by a 1-year manufacturer’s warranty from Waterway Plastics.

✨ Key Features

✅ 0.75 HP Dual-Speed Motor — High speed (3450 RPM) for jet power, low speed (1725 RPM) for quiet filtration and energy savings

✅ 115V / 60Hz Operation — Runs on standard household 115V circuit, ideal for smaller spas and whirlpool baths

✅ Center Discharge Configuration — Intake at center face, discharge exits from top of wet end

✅ 1-1/2″ MBT Connections — Both intake and discharge are 1-1/2″ Male Buttress Thread (~2-7/16″ across threads)

✅ 48 Frame Thru-Bolt Motor — Compact footprint for tight spa cabinet installations

✅ Rotatable Wet End — Discharge can be rotated to match existing plumbing layout

✅ Silicon Carbide Seals with Viton Bellows — Premium seal materials for chemical resistance and long life

✅ 316 Stainless Steel Seal Casing — Corrosion-resistant construction in the most critical seal area

✅ Includes Two 400-4060 Unions — Ships with unions that accept 1-1/2″ PVC pipe

✅ 115 GPM Maximum Flow Rate — Verified flow performance for the 0.75 HP motor

✅ California Title 20 Compliant — Meets energy efficiency requirements

✅ Made in USA — Designed, engineered, and produced by Waterway Plastics in the United States

🔩 Technical specifications

🔧 Parts and fittings for this

Commonly replaced parts

Parts commonly replaced on this item that we stock.

⚡ Electrical Requirements

2-Speed Wiring

• Green = Ground
• White = Common (Neutral)
• Black = High Speed
• Red = Low Speed

⚠️ IMPORTANT: When removing the power cord from your existing pump, label each wire (“Common,” “High Speed,” “Low Speed,” “Ground”) before disconnecting. The connection diagram for the new pump is located on the motor nameplate. Wire terminal positions may differ from your old pump.

⚠️ IMPORTANT ELECTRICAL SAFETY NOTICES:

• All electrical work must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and local building codes.
• Hot tubs and spas require GFCI (Ground Fault Circuit Interrupter) protection as mandated by NEC.
• A dedicated circuit is recommended — do not share with other high-draw appliances.
• Power cord NOT included. Reuse your existing pump cord or purchase a compatible replacement.

🔄 Compatibility Guide

🛒 Recommended items

Discharge Configuration — Center vs Side

This pump has a CENTER DISCHARGE configuration. The intake (suction) faces forward from the center of the wet end, and the discharge exits from the top. This is fundamentally different from SIDE DISCHARGE pumps (Waterway Executive, Hi-Flo, etc.) where both ports exit from the front face.

Port Size — 1-1/2″ Connections

Both intake and discharge use 1-1/2″ MBT connections (approximately 2-7/16″ across the outside of the threads). These connect to 1-1/2″ inner diameter plumbing. If your existing pump has 2″ connections (~3-1/16″ across threads), this pump will NOT fit your plumbing without adapters.

Cross-Reference Part Numbers

The Waterway E-Series 3420310-15 replaces the following older and alternate part numbers:

Waterway Part Numbers:

• 3420310 (older Waterway center discharge)
• 3J20310
• 305641
• 300-1010 (catalog number)
• 3420310-15HZW (Century motor version)

OEM / Third-Party Part Numbers:

• 5030-075
• 5030-250
• 1-00-0192
• 3001010
• 342031015
• SP-07-2N11CB / SP072N11CB
• BX4100-C1

Waterway E-Series Family (Center Discharge, 115V)

Model	HP	Speed	Amps	Notes
3410310-15	0.75 SPL	1-Speed	9.5	Single-speed version
3420310-15 ← THIS PUMP	0.75	2-Speed	8.8 / 2.6	Dual-speed center discharge
3420410-15	1.0	2-Speed	—	1.0 HP version
3420610-15	1.5 SPL	2-Speed	—	1.5 HP version

⚠️ Union Compatibility Warning

There is no industry standard for pump unions — different pump brands (Waterway, Aqua-Flo, Balboa, LX) use their own unique thread styles and sizes. The unions included with this pump (400-4060) are designed for Waterway connections. If you are replacing a pump from a different manufacturer, you will most likely need to cut off your old unions and install the new ones included with this pump. If your heater is directly coupled to the pump wet end, the unions may not be compatible — contact Parts4Tubs for assistance.

⚠️ Old Center Discharge vs New E-Series

The Waterway E-Series replaced the older Waterway center discharge pump. Parts between the two designs are NOT interchangeable. The easiest way to identify which version you have is the faceplate screw count: the old center discharge pump has a 4-screw faceplate, while the new E-Series has a 6-screw faceplate. If you have the old 4-screw version and need wet end parts, you will need to replace the entire wet end with the new E-Series center discharge wet end (310-1120).

🛠️ Installation Requirements

Mounting

Requirement	Specification
Mounting Position	Horizontal
Base Type	Includes mounting feet
Motor Ventilation	Ensure adequate airflow around motor
Service Access	Allow clearance for maintenance and wet end rotation

Plumbing Connections

Connection	Size	Thread OD	Type
Suction (Intake)	1-1/2″	~2-7/16″	MBT — Center face
Discharge (Output)	1-1/2″	~2-7/16″	MBT — Center top (rotatable)

Wet End Rotation

The pump head can be rotated by loosening the motor thru-bolts and turning the pump head. This allows the discharge to be pointed to the 3 o’clock, 9 o’clock, or other positions to match your existing plumbing. Retighten the bolts evenly after rotation.

Installation Notes

⚠️ When matching a replacement pump, verify the motor voltage on your existing pump — not the voltage supplied to the spa. Some spas have 230V supply but use 115V pumps.

⚠️ Pump unions are NOT universal. Use the included 400-4060 unions. You may need to cut off old unions and install the new Waterway unions.

⚠️ Pump must be installed below water level (flooded suction) for proper operation.

⚠️ Never run the pump dry — this damages the mechanical seal.

⚠️ Ensure proper grounding and bonding per NEC requirements.

⚠️ GFCI protection is required by code for all hot tub and spa installations.

⚠️ Power cord NOT included. Reuse your existing cord. Label the wires before disconnecting from the old pump.

🔧 Maintenance Guide

Routine Maintenance

Task	Frequency	Notes
Check for leaks	Monthly	Inspect around seal area and union connections
Inspect union connections	Monthly	Tighten if needed; check O-rings for wear
Clean strainer/filter	As needed	Remove debris to maintain proper flow
Check motor amperage	Annually	Should match rated values (8.8A high / 2.6A low)
Inspect motor vents	Quarterly	Keep clear of debris for proper cooling
Inspect drain plugs	Before winterizing	Use drain plugs to remove standing water

Warning Signs — Replace Pump If:

• Unusual noise such as grinding, screeching, or humming without rotation
• Water leaking from the seal area
• Motor repeatedly trips the circuit breaker
• Reduced water flow or jet pressure
• Motor overheating or automatic shutoff activating frequently

Waterway E-Series OEM Replacement Parts (0.75 HP Center Discharge)

Part Number	Description
310-1120	Complete wet end assembly, 0.75 HP, center discharge, 6-screw faceplate
310-8010	Impeller, E-Series 0.75 HP
319-3100B	Pump seal (PS-1000) — Silicon Carbide / Viton bellows
315-1070	Volute, 6-screw
311-1070	Faceplate, 6-screw
805-0252	Volute O-ring
715-1201	Drain plug
805-0112	Drain plug O-ring
819-1110	Faceplate screws (set of 6)
400-4060	Pump union (accepts 1-1/2″ PVC pipe)

💨 Ideal Applications

Application	Suitability	Notes
♨️ Small to mid-size hot tub jet pump	✅ Yes	0.75 HP ideal for compact spas with 1-1/2″ plumbing
🛁 Whirlpool bath pump	✅ Yes	Center discharge fits many whirlpool bath configurations
♨️ Entry-level spa pump (115V)	✅ Yes	Runs on standard household 115V circuit
♨️ Dream Maker Spa pump replacement	✅ Yes	E-Series replaces older Dream Maker center discharge pumps
♨️ Waterway center discharge pump upgrade	✅ Yes	Replaces old 4-screw center discharge with updated E-Series design
♨️ Large hot tub with 2″ plumbing	❌ No	1-1/2″ connections will not fit 2″ plumbing
♨️ Side discharge pump application	❌ No	Center discharge layout is different from side discharge
♨️ 230V spa application	❌ No	115V only — see Waterway E-Series 230V models if available

❓ Frequently Asked Questions

Q: What makes this pump a “center discharge”? A: In a center discharge pump, the suction port faces forward from the center of the wet end and the discharge port exits from the top of the wet end. This is different from “side discharge” pumps where both ports face forward from the wet end face. Center discharge pumps are commonly used in whirlpool baths, smaller spas, and entry-level hot tubs.

Q: What horsepower is this pump? A: This pump is rated at 0.75 HP. The amperage draw is 8.8 amps on high speed and 2.6 amps on low speed at 115V. When comparing pumps, always match by amperage rather than stated horsepower.

Q: What voltage does this pump use? A: This pump operates on 115V / 60Hz. It plugs into or is wired to a standard 115V household circuit. If your spa requires a 230V pump, this is NOT the correct model.

Q: Does this replace the old Waterway center discharge pump? A: Yes. The E-Series is the current-production replacement for the older Waterway center discharge pump line. However, wet end parts between the old (4-screw faceplate) and new E-Series (6-screw faceplate) are NOT interchangeable. If you have the old 4-screw pump and need parts, you must replace the entire wet end with the E-Series version (310-1120).

Q: What size are the ports? A: Both intake and discharge are 1-1/2″ MBT connections. The outside of the threads measures approximately 2-7/16″. The inner diameter of the suction/discharge is 1-7/8″. These connect to 1-1/2″ inner diameter plumbing or PVC pipe.

Q: Can I use my old unions with this pump? A: Possibly not. Pump unions are NOT standardized across brands. Different manufacturers (Waterway, Aqua-Flo, LX, Balboa) use different thread styles. This pump includes two 400-4060 unions designed for Waterway. If replacing a non-Waterway pump, you will likely need to cut off the old unions and install the included Waterway unions.

Q: Does this pump come with a power cord? A: No. Reuse the power cord from your existing pump. Label the wires (“Common,” “High Speed,” “Low Speed,” “Ground”) before disconnecting from the old pump. The wiring diagram is on the motor nameplate.

Q: What is the flow rate? A: This pump delivers up to 115 GPM at maximum flow.

Q: What warranty is included? A: This pump carries a 1-year manufacturer warranty from Waterway Plastics from date of purchase when installed by a qualified installer. Motors and pumps with part numbers ending in “W” or “N” carry a 1-year warranty from date of manufacture. Contact Parts4Tubs for warranty claim details.

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

Q: What seal does this pump use? A: This pump uses the 319-3100B seal (also known as PS-1000). It features silicon carbide faces, Viton bellows, and a 316 stainless steel casing.

🏆 Why Choose the Waterway E-Series 3420310-15

✅ American-Made Quality — Designed, engineered, and manufactured by Waterway Plastics in the USA since 1973

✅ Reliable Center Discharge Design — Purpose-built for center discharge spa and bath applications

✅ 115V Convenience — Runs on standard household voltage for smaller spa and whirlpool bath installations

✅ Dual-Speed Efficiency — High speed for jets, low speed for quiet, energy-saving filtration

✅ Premium Seal Materials — Silicon carbide seals with Viton bellows and 316 stainless steel casing for long life

✅ 115 GPM Flow Rate — Verified performance for 0.75 HP center discharge applications

✅ Compact 48-Frame Footprint — Fits tight spa cabinet installations (7.35″ × 7″ × 15.00″)

✅ Rotatable Wet End — Discharge can be positioned to match any plumbing layout

✅ Unions Included — Ships with two 400-4060 unions for 1-1/2″ PVC pipe

✅ California Title 20 Compliant — Meets state energy efficiency standards

✅ Comprehensive Parts Availability — All wet end components (impeller, seal, volute, faceplate, O-rings) are individually available

🤝 Why Buy from Parts4Tubs

✅ Fast shipping across the United States

✅ Expert advice from spa and hot tub specialists

✅ Competitive pricing

✅ Full warranty support

✅ Hassle-free returns

✅ Replacement seals, impellers, wet ends, unions, and parts available

✅ Dedicated customer service team

💫 Summary

The Waterway E-Series 3420310-15 is a 0.75 HP dual-speed center discharge jet pump manufactured in the USA by Waterway Plastics. Operating on 115V/60Hz at 8.8 amps (high speed) and 2.6 amps (low speed), this compact 48-frame thru-bolt pump features 1-1/2″ MBT center suction and center discharge connections (approximately 2-7/16″ across threads) with a maximum flow rate of 115 GPM. The wet end is rotatable and uses a 6-screw faceplate design — the current-production replacement for the older 4-screw Waterway center discharge pump. Built with silicon carbide seals, Viton bellows, and a 316 stainless steel seal casing, this pump includes two 400-4060 unions for 1-1/2″ PVC pipe, automatic overload protection, and California Title 20 compliance. All wet end components are individually replaceable (impeller 310-8010, seal 319-3100B, volute 315-1070, faceplate 311-1070). Ideal for small to mid-size hot tubs, whirlpool baths, entry-level spas, and Dream Maker Spa replacements that use center discharge 1-1/2″ plumbing on 115V circuits. Backed by a 1-year Waterway Plastics manufacturer warranty.

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.

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.