⚡ Waterway Executive 56 Spa Pump 3721621-13 — 4.0 HP 2-Speed 230V 56-Frame 2-1/2″ × 2″ Side Discharge

Dual-speed American-made powerhouse with oversized 2-1/2 inch intake for superior flow and energy-saving low-speed filtration

♨️ Product Overview

The Waterway Executive 3721621-13 is a 4.0 HP dual-speed, 56-frame jet pump drawing 12.0 amps on high speed and 4.4 amps on low speed at 230V/60Hz. Designed, engineered, and manufactured in the USA by Waterway Plastics since 1973. This 2-speed configuration delivers full jet power at 3450 RPM on high speed while providing energy-efficient filtration and circulation at 1725 RPM on low speed — significantly reducing electricity costs compared to running a single-speed pump continuously. This pump features an oversized 2-1/2″ MBT center suction (~3.7″ OD threads) paired with a standard 2″ MBT side discharge (~3.1″ OD threads), improving flow performance and reducing noise versus standard 2″ × 2″ configurations. The large 6-1/2 inch diameter wet end is specifically designed for 56-frame motors to deliver higher head pressure. Equipped with Viton seals, double-shielded ball bearings with moisture-resistant grease, four sets of insulated motor windings for increased dual-speed efficiency, split capacitor (start and run) design, and automatic thermal overload protection. The wet end can be rotated in 90-degree increments. Motor brands may include AO Smith Century, US Motors, GE, or others. UL and cUL certified. Backed by a 1-year manufacturer’s limited warranty. This pump is a confirmed replacement for Coast Spas (including Manhattan model) and many other OEM applications.

✨ Key Features

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

✅ 4.0 HP Dual-Speed — Full jet power at 3450 RPM (12.0A) and energy-saving filtration at 1725 RPM (4.4A)

✅ Oversized 2-1/2″ Intake — Larger suction port improves flow performance and reduces operating noise

✅ Large 6-1/2″ Diameter Wet End — Executive wet end specifically designed for 56-frame motors delivers higher head pressure

✅ 56-Frame Motor — Cooler & Quieter — Larger motor runs at lower temperatures for added strength and longer life

✅ Viton Seals — Premium chemical-resistant seals compatible with salt chlorine generators and aggressive sanitizers

✅ Four Insulated Motor Windings — Dual-speed motors feature increased efficiency versus standard windings

✅ Double-Shielded Ball Bearings — Moisture-resistant grease for quieter operation and extended bearing life

✅ Split Capacitor Design (Start & Run) — Reduced energy consumption

✅ Thermal Overload Protection — Automatic motor protection extends life expectancy

✅ 4-Position Wet End Rotation — Rotates every 90° for flexible plumbing alignment

✅ UL and cUL Certified — Full North American electrical safety certifications

✅ 1-Year Manufacturer’s Limited Warranty — Backed by Waterway Plastics

🔩 Technical Specifications

Specification	Value
Manufacturer	Waterway Plastics (USA)
Series	Executive 56-Frame
Part Number	3721621-13 (updated to ME-40226-25)
Motor Model	PF-40-2N22C (older) / PF-35-2N22M (current) — same pump
Pump Type	Jet Pump — Side Discharge
Horsepower	4.0 HP
Speed Settings	2-Speed (Dual Speed)
High Speed RPM	3450
Low Speed RPM	1725
Voltage	220-240V (listed as 230V nominal)
Frequency	60 Hz
Phase	Single Phase
Amperage (High Speed)	12.0 Amps
Amperage (Low Speed)	4.4 Amps
Frame Type	56 Frame (56Y) Thru-Bolt
Wet End Diameter	6-1/2″
Discharge Type	Side Discharge
Discharge Size	2″ MBT — ~3.1″ OD threads
Suction Size	2-1/2″ MBT — ~3.7″ OD threads
Suction Style	Center
Discharge Rotation	4 positions — 90° increments
Motor Windings	Four insulated windings (dual-speed design)
Seal Type	Viton (PS-1000 / 319-3100B)
Impeller Part Number	310-4190 / 310-4190B (4.0 HP Executive 48/56 Frame)
Wet End Part Number	310-1440 (4HP, 56FR, 2-1/2″ suc × 2″ dis)
Bearings	Double-shielded ball bearings with moisture-resistant grease
Capacitor	Split capacitor (start and run)
Motor Protection	Thermal overload (automatic)
Cord	Sold separately
Unions	NOT INCLUDED — sold separately
Certifications	UL, cUL
Country of Origin	Made in USA
Warranty	1-Year Manufacturer’s Limited Warranty

🔌 Electrical Requirements

Electrical Spec	Requirement
Supply Voltage	220-240V (230V nominal)
Frequency	60 Hz
Phase	Single Phase
Amperage (High Speed)	12.0 A
Amperage (Low Speed)	4.4 A
High Speed RPM	3450
Low Speed RPM	1725
Motor Windings	Four insulated windings
Overload Protection	Automatic thermal overload (built-in)
Cord Type Required	4-wire (dual-speed) pump cord — see cord note above
Certifications	UL, cUL

⚠️ IMPORTANT ELECTRICAL SAFETY:

All electrical installations must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and local building codes. This 230V pump must be connected to a supply circuit protected by a Ground-Fault Circuit Interrupter (GFCI). A dedicated circuit is required — do not share with other appliances. Improper grounding can cause serious injury and damage the motor, voiding the warranty.

⚠️ Wiring Warning: When removing the power cord from your old pump, label your wires “Common,” “High Speed,” and “Low Speed” before disconnecting. The connection diagram for the new motor is located on the nameplate. Do NOT assume wire positions match your old pump — motor model changes may alter terminal positions. This pump does NOT come with a cord pre-installed.

⚠️ Can Be Wired as Single-Speed: A 2-speed pump CAN be wired as single-speed by connecting only the high-speed terminal and leaving the low-speed disconnected. However, a single-speed pump CANNOT be wired as 2-speed.

🔄 Compatibility Guide

CRITICAL: 3721621-13 vs 3721621-1D — Different Port Configurations

Model	Suction (Intake)	Discharge (Outlet)	Thread OD (Suction)	Thread OD (Discharge)
3721621-13 (THIS PUMP)	2-1/2″ MBT (Center)	2″ MBT (Side)	~3.7″	~3.1″
3721621-1D	2″ MBT (Center)	2″ MBT (Side)	~3″ / ~3.1″	~3″ / ~3.1″

⚠️ These are NOT interchangeable without plumbing modifications. Measure the outside diameter of the threads on your existing pump’s suction port: approximately 3.7″ = 2-1/2″ (order 3721621-13); approximately 3″/3.1″ = 2″ (order 3721621-1D).

Confirmed OEM Spa Brand Replacements

Coast Spas:

• 3721621-0306 — Coast Spas including Manhattan model (confirmed by multiple Amazon reviews as exact replacement for 2005+ Coast Spas)

Aquastorm by Infinity Spas — confirmed replacement

Massage Master XLT — confirmed replacement

Super-Flo — confirmed replacement

Frame Size Reference

Frame	Bolt Pattern (Adjacent)	Bolt Pattern (Diagonal)
48-Frame	3-5/8″ apart	5-3/16″ in X pattern
56-Frame (THIS PUMP)	4-1/8″ apart	5-3/4″ in X pattern

⚠️ Do NOT overpower your spa by going from a 48-frame motor to a 56-frame motor. If your existing pump is a 48-frame, replace with a 48-frame pump (such as the 3421621-13 series).

Waterway Executive 56-Frame 4HP Family (All Port/Speed Variants)

Model	Speed	Ports (Suc × Dis)	Amperage	Updated P/N	Notes
3721621-13 (THIS PUMP)	2-Speed	2-1/2″ × 2″	12.0/4.4A	ME-40226-25	Oversized suction, dual-speed
3721621-1D	2-Speed	2″ × 2″	12.0/4.4A	ME-40226-20	Standard ports, dual-speed
3711621-13	1-Speed	2-1/2″ × 2″	12.0A	—	Oversized suction, single-speed
3711621-1D	1-Speed	2″ × 2″	12.0A	—	Standard ports, single-speed

Union Requirements (NOT Included — Sold Separately)

Port	Union Part Number	Description
Suction (2-1/2″)	400-5990	2-1/2″ union × 2″ slip
Discharge (2″)	400-5570	2″ FBT × 2″ slip
Suction O-Ring	O-245	2-1/2″ union o-ring
Discharge O-Ring	O-43	2″ union o-ring

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📐 Alternate Part Numbers

Primary / Updated Designations

Part Number	Notes	Source
3721621-13	Primary Waterway Executive part number (2-1/2″ × 2″, 2-speed)	Parts4Tubs, all retailers
ME-40226-25	Updated Waterway replacement designation (same pump)	SpaParts.com, SpaDepot, ReedPoolProducts, PoolAndHotTubDepot
3721621-13HZN	OEM Waterway variant (Century motor)	HotTubOutpost
372162113	Concatenated format	EasySpaParts, SpaCare
WW372162113	Distributor code	EasySpaParts, SpaCare
3721621	Base model number (without suffix)	EasySpaParts

Motor Model Designations (All Same Pump — Waterway Changed P/Ns)

Motor Model	Status	Source
PF-40-2N22C / PF401N22C	Older motor model	EasySpaParts, SpaGuts, SpaCare
PF-35-2N22M	Current motor model (updated)	PoolAndHotTubDepot
PF-40-2N22M / PF-40-2N22MC	Alternate motor model	EasySpaParts, SpaGuts
PF-30-2N22C / PF-30-2N22M / PF-30-2N22MC	Alternate motor model	SpaGuts, SpaDepot
PF-35-2N22C	Alternate motor model	SpaGuts
PF-40-2NCG5	Alternate motor model	EasySpaParts, SpaGuts
P240E5252024	Alternate motor model	EasySpaParts, SpaGuts
372162A-13	Motor/pump variant	EasySpaParts, SpaGuts

⚠️ WARNING: Do NOT use PF- model numbers to select a replacement pump. Waterway has produced up to 4 different pump variations with the same PF- number that are NOT interchangeable.

Sub-Variant / OEM Part Numbers

Part Number	Notes	Source
3721621-0D	Sub-variant	EasySpaParts, SpaGuts
3721621-03	Sub-variant	EasySpaParts, SpaGuts
3721621-0385V	Sub-variant	EasySpaParts, SpaGuts, SpaDepot
3721621-0385B	Sub-variant	SpaDepot
3721621-1385V	Sub-variant	EasySpaParts, SpaGuts
3711621-0385V	Sub-variant (note: 3711 prefix but same application)	EasySpaParts, SpaGuts
3721621-5985	Sub-variant	EasySpaParts, SpaGuts
3E21821-6310	Alternate designation	SpaDepot
3721621-0306	Coast Spas (including Manhattan model)	HotTubOutpost, Amazon reviews

Distributor / Retailer SKU Cross-References

Part Number	Source / Notes
5039-409	EasySpaParts, SpaCare
301916	Leslie’s Pool Supplies
1-00-0120	EasySpaParts, SpaCare
34-270-3384	EasySpaParts, SpaCare
34-270-3596	EasySpaParts, SpaCare
15-350-0045	EasySpaParts, SpaCare
15-350-3196	SpaGuts, SpaCare

Motor Part Numbers (Used With This Pump)

Motor P/N	Motor Brand	Source
0-187563-02	—	SpaGuts
5KCP49UN9096X	GE	SpaGuts
R63MWENA-4727	—	SpaGuts

Related 2″ × 2″ Version (DIFFERENT Wet End — Same Motor)

Part Number	Notes	Source
3721621-1D	Executive 4HP 2-Speed 230V 2″ × 2″ (SAME port sizes)	HotTubOutpost, Parts4Tubs
ME-40226-20	Updated designation for 3721621-1D (2″ × 2″) — DISCONTINUED per HotTubOutpost	HotTubOutpost
3721621-1W	EX2 variant (2″ × 2″) — also 56-frame, 4HP, 2-speed, 12.0/4.4A	Parts4Tubs

⚠️ 3721621-1D Status: HotTubOutpost lists the 3721621-1D as DISCONTINUED — replaced by ME-40226-B20. The LX 56WUA400-II is listed as a compatible lower-cost 2″ × 2″ alternative.

Lower-Cost Alternatives (Same Performance — Verify Amperage Match)

Model	Brand	Ports	Amperage	Notes
56WUA400-II	LX Lingxiao	2″ × 2″	12.0/4.4A	Lower cost, 56-frame, Made in China, 1-year warranty
56WUA400-II(NF)	LX Lingxiao	2″ × 2″	12.0/4.4A	Bracketless version (no base — requires bracket)

⚠️ LX pumps have 2″ × 2″ ports only. No LX equivalent exists with a 2-1/2″ suction for this pump.

Replacement Pump Components (Individual Parts)

Component	Part Number	Notes	Source
Wet End (4HP, 56FR, 2-1/2″ × 2″)	310-1440	Complete: volute, seal, impeller, wear ring, suction cover, o-ring, drain plug, screws. Motor & unions sold separately.	Pool-Spa-Supplies, HotTubOutpost
Wet End (4HP, 56FR, 2″ × 2″)	310-1740	For -1D version — DIFFERENT suction size	HotTubOutpost
4HP Impeller	310-4190 / 310-4190B	Executive 48/56 Frame 4.0 HP impeller	SpaCare
Seal (Viton)	PS-1000 / 319-3100B	Standard Waterway Executive seal — American manufactured	SpaCare
Faceplate (2-1/2″ suction)	311-1210 / 311-1210B	Executive 48/56 Frame — 2-1/2″ suction cover	SpaCare
Faceplate (2″ suction)	311-1220	For -1D version — DIFFERENT suction size	SpaCare
Faceplate O-Ring	805-0261	Executive 48/56 Frame suction cover o-ring	SpaCare
Drain Plug O-Ring	805-0111	Executive 48/56 Frame	SpaCare
Wear Ring (4-5HP)	319-1370	DIFFERENT from 1-3HP wear ring (319-1380)	SpaCare
56-Frame Volute	315-1220 / 315-1220B	Executive 56-frame housing	SpaCare
Union (2-1/2″ × 2″ Slip)	400-5990	Suction side union	HotTubOutpost
Union (2″ FBT × 2″ Slip)	400-5570	Discharge side union	HotTubOutpost
Union O-Ring 2-1/2″	O-245	Suction union gasket	HotTubOutpost
Union O-Ring 2″	O-43	Discharge union gasket	HotTubOutpost
Rubber Motor Base	319-0019	Vibration-dampening rubber motor mount	HotTubOutpost
Drain Plugs	715-1201	For faceplate	HotTubOutpost
2-Speed AMP Cord	30-1001C	4-pin AMP pump cord (2-speed)	HotTubOutpost
Molded LIT Cord	30-0220-48	Molded LIT pump cord	HotTubOutpost
AMP to Mini-JJ Adapter	30-1220-L6	Adapter for JJ connector spa packs	HotTubOutpost

⚠️ Impeller Warning: The 4-5HP impellers use a different size wear ring (319-1370) than 1-3HP impellers (319-1380). Do NOT install a higher-HP impeller — it will overstrain the motor and cause overheating.

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🛠️ Installation Requirements

Mounting

Requirement	Specification
Mounting Position	Horizontal — below water level (flooded suction)
Base	Level surface with adequate drainage
Ventilation	Ample clearance around motor for air cooling
Access	Sufficient clearance for maintenance and wet end rotation
Shut-Off Valves	Recommended on both inlet and outlet for future maintenance

Plumbing

Connection	Size	Thread OD	Notes
Suction (Center)	2-1/2″ MBT	~3.7″	Connects to 2-1/2″ ID plumbing
Discharge (Side)	2″ MBT	~3.1″	Connects to 2″ ID plumbing

⚠️ DIFFERENT PORT SIZES: The suction (intake) connects to 2-1/2″ plumbing and the discharge (outlet) connects to 2″ plumbing.

Installation Notes

⚠️ Flooded Suction Required: Pump must be installed below water surface. Self-priming — water must be above pump in order to operate properly. If installing near or above waterline (common for in-ground spas), a pump pot is required.

⚠️ Never Run Pump Dry: Ensure the pump is primed and filled with water before starting.

⚠️ HAND TIGHTEN UNIONS ONLY: Do NOT use a wrench or any adhesives or solvents. Do NOT use pipe sealant/pipe dope. Use only Teflon tape or sealing compounds approved for use with plastic.

⚠️ Pressure Test Warning: Plumbing pressure tests should not exceed 40 PSI.

⚠️ Discharge Rotation: Wet end can be rotated in 90-degree increments by loosening the four thru-bolts at the back of the motor and turning the wet end. Discharge can point to 12, 3, 6, or 9 o’clock positions.

⚠️ Cord Sold Separately (Most Retailers): Common cord options for 2-speed pumps: 30-1001C (4-pin AMP), 30-0220-48 (molded LIT), or mini-JJ with 30-1220-L6 adapter. Label your old wires before disconnecting.

⚠️ Unions NOT Included: Sold separately. Suction requires 400-5990 (2-1/2″ × 2″ slip); discharge requires 400-5570 (2″ FBT × 2″ slip).

⚠️ Bonding & Grounding: Improper grounding voids warranty and creates electrical hazards. Follow all NEC requirements.

⚠️ GFCI Protection Required: All spa installations require GFCI protection per the NEC.

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⚙️ Maintenance Guide

Routine Maintenance

Task	Frequency	Notes
Check for leaks	Monthly	Inspect around seal area, unions, and volute housing
Inspect plumbing connections	Monthly	Unions should be hand-tight only
Check amperage draw	Annually	High: ~12.0A / Low: ~4.4A at 230V
Keep motor clean	Quarterly	Ensure all air openings are free from debris
Verify GFCI operation	Monthly	Press test button to confirm proper function
Check mounting and vibration	Quarterly	Motor base should be secure and level
Verify both speeds operate	Monthly	Test high and low speeds to confirm proper function

Warning Signs — Replace Pump If:

• Unusual noise (grinding, screeching, or humming without rotation)
• Water leaking from seal area between motor and wet end
• Motor repeatedly trips circuit breaker or GFCI
• Noticeably reduced water flow or weak jets
• Motor overheating or burning smell
• Motor hums but won’t start (possible capacitor failure)
• One speed works but the other doesn’t (possible winding failure)
• Excessive vibration even on solid mounting
• Amperage draw significantly different from rated values

Seal Information

Detail	Specification
Seal Type	Viton
Seal Part Number	PS-1000 / 319-3100B
Material	High chemical resistance — compatible with salt chlorine generators

⚠️ Replace seal at first sign of leakage. The complete wet end (310-1440) comes pre-assembled with a new seal, impeller, wear ring, and all housing components — often more cost-effective than individual seal replacement.

⚠️ Seal Warning: The Waterway PS-1000 is NOT interchangeable with the Gecko Aqua-Flo PS-200 or LX SEAL-56WUA. Always match the seal to the wet end brand.

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🎯 Ideal Applications

Application	Suitability	Notes
♨️ Hot tub dual-speed jet pump (12.0/4.4A, 230V, 56-frame, 2-1/2″ suction)	✅ Yes — Primary application	Full jet power + energy-saving filtration
♨️ Coast Spas replacement (including Manhattan model)	✅ Yes — Confirmed OEM	3721621-0306 cross-reference
♨️ Single-pump spa systems (jet + filtration)	✅ Yes	Low speed handles filtration, high speed for jets
♨️ Multi-pump spa systems	✅ Yes	Can serve as primary or secondary jet pump
♨️ Salt water / chlorine generator spas	✅ Yes	Viton seals provide chemical resistance
♨️ Spas with standard 2″ × 2″ plumbing	❌ No — Wrong suction size	Use 3721621-1D instead
♨️ 115V spa installations	❌ No	This is a 230V pump only
♨️ 48-frame installations	❌ No — Will overpower spa	Use 48-frame equivalent
🛁 Whirlpool bath	❌ No	Far too powerful for bath applications

❓ Frequently Asked Questions

Q: What is the difference between 3721621-13 and 3721621-1D? A: Port sizes. The 3721621-13 (this pump) has a 2-1/2″ suction (~3.7″ OD) and standard 2″ discharge (~3.1″ OD) — DIFFERENT port sizes. The 3721621-1D has 2″ suction and 2″ discharge — SAME port sizes (~3″/3.1″ OD both). Both are 4HP, 2-speed, 230V, 12.0/4.4A with the same motor but DIFFERENT wet ends.

Q: What is the updated part number? A: Waterway has replaced 3721621-13 with ME-40226-25. Both identify the same pump. The updated motor model is PF-35-2N22M (replacing PF-40-2N22C).

Q: Is this a 4.0 HP pump? A: Rated at 4.0 HP by Waterway. However, HP ratings vary by rating method (SPL-HP, BHP, continuous, etc.). The 12.0A high / 4.4A low amperage at 230V is the most reliable specification for replacement matching. Do NOT install an oversized pump.

Q: Will this fit my Coast Spa? A: Yes — this pump is a confirmed replacement for Coast Spas including the Manhattan model (OEM part 3721621-0306). Multiple Amazon reviewers confirm exact fit for 2005+ Coast Spas with 2-1/2″ suction plumbing.

Q: Are unions included? A: No. Unions sold separately. Suction: 400-5990 (2-1/2″ × 2″ slip); discharge: 400-5570 (2″ FBT × 2″ slip). O-rings: O-245 (suction) and O-43 (discharge).

Q: Is a cord included? A: Varies by retailer. Most retailers ship without cord. The updated ME-40226-25 from some distributors may include a cord. Verify with Parts4Tubs at time of purchase. Common 2-speed cord options: 30-1001C (AMP), 30-0220-48 (LIT), or mini-JJ with adapter 30-1220-L6. Your existing 2-speed cord can usually be reused.

Q: Can this pump be wired as single-speed? A: Yes. Connect only the high-speed terminal and leave low-speed disconnected. This provides 12.0A, 3450 RPM single-speed operation.

Q: What wet end does this pump use? A: 310-1440 — Executive 4HP, 56-frame, 2-1/2″ MBT suction × 2″ MBT discharge. This is DIFFERENT from 310-1740 (2″ × 2″) on the 3721621-1D. The wet end is shared with the single-speed 3711621-13.

Q: What about the drain plug change? A: Waterway is removing two of the three drain plugs from the front of the wet end (side ports) as a running change. The bottom drain plug remains. For installations requiring side drain ports, those can still be drilled and tapped on location.

Q: What seal and impeller does this pump use? A: Seal: PS-1000 / 319-3100B (Viton). Impeller: 310-4190 / 310-4190B (4HP, 48/56 Frame). Wear ring: 319-1370 (4-5HP — different from 1-3HP).

Q: Is there a lower-cost alternative? A: The LX Lingxiao 56WUA400-II is a compatible 56-frame, 2-speed, 230V, 12.0/4.4A pump at a lower price point. However, LX pumps only come in 2″ × 2″ port configuration — there is no LX equivalent with a 2-1/2″ suction for this pump.

Q: What motor brand will I receive? A: Waterway may supply AO Smith Century, US Motors, GE, or other brands without notice. Performance specifications remain consistent.

Q: How do I measure frame size? A: Measure the distance between consecutive motor through bolts. 4-1/8″ apart = 56-frame (this pump). 3-5/8″ apart = 48-frame.

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

Q: What warranty is included? A: 1-year manufacturer’s limited warranty from date of purchase (if installed by a qualified installer). Parts failing during warranty are repaired or replaced. Does not cover freezing, negligence, improper installation, GFCI trips due to improperly maintained water chemistry, or labor/shipping costs. Proof of purchase required.

📥 Downloads & Resources

📄 Waterway 48/56 Frame Executive, EX2, & Viper Pump Installation Manual (PDF) — Official Waterway Plastics installation instructions

🌟 Why Choose the Waterway Executive 3721621-13

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

✅ Dual-Speed Efficiency — Full jet power on high speed, energy-saving filtration on low speed

✅ Oversized 2-1/2″ Intake — Improved flow and reduced noise over standard 2″ intake

✅ Large 6-1/2″ Wet End — Higher head pressure for powerful jet performance

✅ Premium Viton Seals — Superior chemical resistance for salt water compatibility

✅ Double-Shielded Ball Bearings — Quieter operation and extended motor life

✅ Four Insulated Windings — Increased dual-speed efficiency

✅ Split Capacitor + Thermal Protection — Energy savings with built-in motor protection

✅ Confirmed Coast Spas Replacement — Exact OEM fit for Coast Spas including Manhattan

✅ UL and cUL Certified — Full North American safety certifications

✅ Proven Track Record — Waterway Plastics: innovation and excellence since 1973

🤝 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

✅ Full warranty support

✅ Hassle-free returns

✅ Compatible pump cords, unions, seals, wet ends, impellers, and replacement parts available

🔇 Summary

The Waterway Executive 3721621-13 is a 4.0 HP dual-speed, 230V/60Hz jet pump drawing 12.0 amps high / 4.4 amps low with a 56-frame (56Y) thru-bolt motor at 3450/1725 RPM. Made in the USA by Waterway Plastics. Updated part number: ME-40226-25 (same pump). Updated motor model: PF-35-2N22M (replacing PF-40-2N22C). This pump features an oversized 2-1/2″ MBT center suction (~3.7″ OD) paired with 2″ MBT side discharge (~3.1″ OD) — DIFFERENT port sizes for improved flow and reduced noise. Large 6-1/2″ diameter wet end designed for 56-frame motors delivers higher head pressure. Premium Viton seals for salt water compatibility, double-shielded ball bearings, four insulated windings, split capacitor, and automatic thermal overload protection. Wet end rotates in 90° increments. Confirmed replacement for Coast Spas (3721621-0306), Aquastorm by Infinity Spas, Massage Master XLT. Also known as ME-40226-25, PF-40-2N22C, PF-35-2N22M, 3721621-0306, 3721621-0385V, 3E21821-6310, 1-00-0120, 5039-409, 301916, and many more. Wet end 310-1440, impeller 310-4190, seal PS-1000/319-3100B, faceplate 311-1210, wear ring 319-1370. Unions NOT included (suction: 400-5990, discharge: 400-5570). Cord varies by retailer. UL and cUL certified. 1-year manufacturer’s limited warranty. Available now at Parts4Tubs.

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.