🔌 Sundance / Jacuzzi 6600-724 Spa Circuit Board – LX-10 Rev 3.57+ (1-Pump, With Circulation Pump, 120V/240V Convertible)

Trusted circuit board replacement for years of trouble-free soaking in your Sundance® or Jacuzzi® hot tub.

📋 Product Overview

The 6600-724 is the current factory replacement circuit board for 1-pump Sundance® and Jacuzzi® J-300 LED series hot tubs built on the Spa Builders LX-10 control platform and equipped with a 24-hour circulation pump. It is the official progression part number that supersedes the older 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, and 6600-226 boards.

This PCB drives one 2-speed jet pump, a dedicated 24-hour circulation pump, the heater, ozonator output, and spa light, while communicating with the topside LCD panel for temperature control, programmable filter cycles, and LX-10 self-diagnostics. It is a 120V / 240V convertible design — jumper-selectable for either supply voltage — which is what lets it serve the J-300 LED convertible lineup and the Sundance 780-series 1-pump-with-circ spas.

✨ Key Features

• ✅ Direct factory replacement for LX-10 1-pump-with-circ systems – supersedes 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, and 6600-226 per official Jacuzzi circuit-board history
• ✅ Supports dedicated 24-hour circulation pump – this is the with-circ LX-10 variant (the no-circ variant is the 6600-722)
• ✅ 120V / 240V convertible – JP1 jumper selects 120V / 15A Logic or 240V / 40A Logic operation
• ✅ Three large onboard relays – handles low-speed jet pump, high-speed jet pump, and heater
• ✅ Ships with current Rev 3.57+ logic chip – half-hour filter cycles, 106°F overtemp protection, programmable circulation, and (on newer 3.61A shipments) Smart Logic energy-saving
• ✅ Runs LX-10 self-diagnostics – topside LCD displays SN1, SN2, FL1, FL2, COL, ICE, OH, and watchdog (—) codes
• ✅ Wide temperature set range – 65°F to 104°F (18°C to 40°C) in 1°F increments
• ✅ Built-in freeze and overheat protection – automatic pump/heater activation at 55°F (12.8°C); overtemp cut-off at 106°F (41°C) on Rev 3.57+ chips
• ✅ Ozone-ready output – energizes ozonator during filter cycles when equipped
• ✅ Integrated spa-light control – with auto time-out
• ✅ OEM Jacuzzi / Sundance board – same board manufacturers have used across the J-300 LED family since 2002 (with updated logic chips)
• ✅ Covered under original manufacturer’s warranty

⚙️ Technical Specifications

Specification	Value
Part Number	6600-724
Control System	Spa Builders LX-10
Current Logic Chip	Rev 3.57+ (ships with Rev 3.57; newer stock may ship with Rev 3.61A)
Board Configuration	1-Pump with 24-Hour Circulation Pump
Onboard Relays	3 large relays (low-speed jet pump, high-speed jet pump, heater)
Voltage Mode	120V / 15A Logic or 240V / 40A Logic (JP1 pins 1-2 jumper-selectable)
Frequency	60 Hz (North America)
Jet Pump	2-speed (low / high)
Circulation Pump	Dedicated, continuous-duty (programmable run time)
Heater Switching	220 VAC load across heater relay (K7-com / K6-com terminals)
Transformer Secondary	12.4 VAC
Temperature Set Range	65°F to 104°F (18°C to 40°C)
Display Units	°F or °C, selectable via JP1 jumper
Overtemp (OH) Trip	106°F (41°C) on Rev 3.57+ chips (2010+ chip feature)
Watchdog (—) Trip	118°F (48°C) – full system disable
Freeze (ICE) Protection	Activates at 55°F (12.8°C); recovers at 65°F
Cool (COL) Threshold	20°F (11°C) below set point (Economy Mode only)
Filter Cycles	Programmable ½-hour filter cycles (Rev 3.57+ chips)
Programmable Circulation	✅ Yes
Smart Logic Energy-Save	✅ On Rev 3.61A chip shipments (deducts non-programmed heat-call runtime from next day’s filter cycle)
Compatible Temp Sensor	6600-166 (curled-finger connectors)
Compatible Hi-Limit Sensor	Varies by spa model — commonly 6600-068 (Sundance) or 6600-144 (Jacuzzi J-300) — verify existing part number
Connection Type	Push-on (spade) connectors + surface-mount heater terminals (on current production)
Warranty	Covered under original manufacturer’s warranty
Returnable	⚠️ No – circuit boards are non-returnable

ℹ️ Voltage note: This is a true 120V / 240V convertible LX-10 board — the same hardware works on both supply voltages depending on the JP1 jumper configuration. Most US residential Sundance / Jacuzzi spas using this board are wired for 240V / 60Hz, but the J-300 LED J-310 / J-315 / J-325 “Convertible” lineup and certain 780-series spas can be wired for 120V service. Always match the jumper to your spa’s actual wired supply voltage before energizing.

🔗 Compatibility Guide

Compatible Jacuzzi® J-300 LED Spa Models (North America 60Hz)

Per the official Jacuzzi circuit-board history, the 6600-724 covers the 1-pump Convertible models in the J-300 LED family:

Series / Model	Years	Notes
J-300 LED J-310, J-315 (Convertible)	2002–2006	120V/240V convertible, with circ
J-300 LED J-325 (Convertible)	2004	120V/240V convertible, with circ
J-300 LED J-315 (Convertible)	2007–2011	120V/240V convertible
J-300 LED J-325 (120/240V Convertible)	2008–2011
J-300 LED J-325, J-315 (Convertible)	2012–2013

⚠️ The 2005–2007 J-325 240V Model (non-convertible) and the 2002–2003 J-320 use the 6600-726, not the 6600-724. Verify your exact model/year before ordering.

Compatible Sundance® Spa Models

Series / Model	Years	Notes
Sundance 780® Dover	2014 – 03/2017	1 jet pump + circ
Sundance 780® Metro, Solo, Caprio	2005+ (1-pump with circ)	Verify configuration
Sundance 780® Tango	With circ	Verify configuration
Sweetwater® Lagunas (2-Speed)	2003–2004
Sundance 850E® Series (1-pump with circ)	2005+	Verify configuration
Sundance Portofino® (Solo)	1999 (LX-10 Series with 3 large relays)	Original application

OEM Part Numbers This Board Replaces

Old Part Number	Description
6600-086	Original J-300 LED / Sundance 1-pump-with-circ LX-10 board
6600-286	Later-revision replacement for 6600-086 / 6600-085
6600-044	Prior replacement for 6600-286 (same board, different micro chip)
6600-085	Earlier-revision Sundance / Sweetwater board
6600-208	Alternate OEM designation
6600-226	Alternate OEM designation
3-70-0348	Sundance OEM cross-reference designation

⚠️ Verify before ordering: (1) Your spa has a dedicated circulation pump – if it does not, you need the 6600-722 instead. (2) Your spa has only one jet pump – 2-jet-pump Jacuzzi J-300 models use the 6600-726. (3) Your existing board part number matches one of the numbers above.

Compatible Topside Panels (indicative — verify by spa model)

Panel Part Number	Series
2600-321	J-300 LED series
2600-331	J-300 LED series

Contact Parts4Tubs with your topside part number and spa model if you are uncertain.

🎛️ Board Functions & Controls

Pump Control

Output	Function
Pump 1 – Low Speed	Heat-assist / filter cycle
Pump 1 – High Speed	Jet action
Circulation Pump	Dedicated 24-hour filtration circuit, programmable run time

Heater Control

Feature	Specification
Heater Relay	K7-com / K6-com, 220 VAC load
External Hi-Limit	Required – sensor type varies by spa model
Set Range	65°F – 104°F (18°C – 40°C)
Overtemp Cut-Off (OH)	106°F (41°C) on Rev 3.57+ chips
Watchdog Cut-Off (—)	118°F (48°C) – entire system disabled

Additional Controls

Function	Capability
Spa Light	Integrated on/off with auto time-out
Ozone	Energized during filter cycles when equipped
Display Units	°F or °C (JP1 jumper)

Filter Cycle & Logic Features by Chip Revision

Chip Revision	Features
Rev 3.57 (2004-2011 shipments)	½-hour filter cycles, 106°F overtemp (2010+), programmable circulation
Rev 3.61A (2012-2013+ shipments)	½-hour filter cycles, 106°F overtemp, programmable circulation, Smart Logic energy-save (deducts off-cycle heat-call time from next day’s filter cycle)

JP1 Jumper Reference (Spa Builders LX-10)

Pins	Jumper ON	Jumper OFF
1-2	120V / 15A logic	240V / 40A logic
3-4	Centigrade (°C)	Fahrenheit (°F)

🛠️ Installation Requirements

⚠️ Installation must be performed by a licensed electrician in compliance with the National Electrical Code (NEC), NEC Article 680 (Spas and Hot Tubs), and all local codes. Circuit boards are not plug-and-play — correct voltage jumper setup and jumper/dipswitch configuration must match the spa’s wiring and heater configuration. Always consult the wiring schematic on the back of the spa pack cover.

Pre-Installation Checklist

• [ ] Confirm your spa has BOTH one jet pump AND a dedicated 24-hour circulation pump
• [ ] Confirm your existing board P/N is 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, 6600-226, or already 6600-724
• [ ] Verify spa year and model against the compatibility tables above
• [ ] Disconnect all power at the house breaker AND the spa disconnect box
• [ ] Photograph every wire and connector position on the existing board before removal
• [ ] Allow capacitors to discharge — wait at least 5 minutes after power-off
• [ ] Verify JP1 jumper setting matches your wired supply voltage (120V or 240V)
• [ ] Inspect temperature sensor (6600-166) and hi-limit sensor; replace as a matched set if the spa has thrown SN1 or SN2 codes

Electrical Requirements

Requirement	Specification
Supply Voltage	120V / 60Hz or 240V / 60Hz (per JP1 and spa wiring)
Circuit Breaker	Per spa manufacturer rating for your model and voltage configuration
GFCI Protection	Required (NEC Article 680)
Grounding	Equipment grounding + bonding required (NEC Article 680)
Dedicated Circuit	Required
Disconnect Box	Required within line of sight of the spa (NEC)

Key Connection Reference Points

Reference (per LX-10 service doc)	Function
K7-com to K6-com	Heater load terminals (220 VAC during heat call)
J4 (Yellow–Yellow)	Transformer secondary output, 12.4 VAC
Sensor plug	6600-166 temperature sensor input
Hi-limit	Hi-limit snap-switch input (model-specific sensor)
JP1	Voltage and °F/°C configuration jumper

💡 Tip: Current production 6600-724 boards include screw-terminal heater connections for the forked-lug heater wiring used in newer Sundance/Jacuzzi models, alongside the traditional spade connectors for older models. Do not buy a circuit board based on appearance alone — many LX-10 boards look identical but have different logic chips and terminal configurations.

⚠️ Safety Warnings

Electrical Safety

• ⚠️ ALWAYS disconnect power at the house breaker before any work on the spa pack
• ⚠️ Installation must be done by a licensed electrician
• ⚠️ Verify the supply voltage (120V or 240V) matches the JP1 jumper configuration BEFORE energizing — miswired voltage can destroy the heater, pump, and board
• ⚠️ GFCI protection is mandatory for all hot-tub installations (NEC Article 680)
• ⚠️ Never operate the spa with the control box cover removed
• ⚠️ All wiring must comply with the NEC and local electrical codes

Water & Electrical Safety

• ⚠️ Protect the board and control box from any water ingress during and after installation
• ⚠️ Inspect every seal and gasket on the control-box enclosure before closing up
• ⚠️ Never touch electrical components with wet hands

Post-Installation

• ⚠️ Verify the circulation pump runs continuously (per programmed cycle) and the jet pump low/high speeds operate correctly
• ⚠️ Confirm heater “call for heat” indication and measure actual heater current
• ⚠️ Monitor the topside LCD for any error codes during the first full heat cycle
• ⚠️ Test hi-limit and temperature sensor response before returning the spa to service

🔍 Error Codes & Troubleshooting (Spa Builders LX-10)

Code	Meaning	Suggested Action
SN1	Non-functional high-temperature (hi-limit) sensor	Check sensor plug seating. Test hi-limit sensor resistance. Replace as a matched sensor set if out of spec.
SN2	Non-functional temperature sensor	Check sensor plug seating. Test 6600-166 resistance (decreases as temp rises). Replace if out of spec.
FL1	Water-flow problem — pressure / flow switch did not close with pump running	Check water level, prime circulation pump, clean filter, inspect flow switch, bleed airlock at circ-pump hose.
FL2	Pressure / flow switch closed while pump is OFF	Switch stuck closed or shorted — test and replace as needed.
COL	Cool condition — water 20°F (11°C) below set point (Economy Mode only)	No action needed; low-speed pump and heater will automatically recover temperature.
ICE	Freeze condition detected at ≤55°F (12.8°C)	No action needed; pump + heater activate automatically until ≥65°F.
OH	Overtemp — water reached 106°F (41°C) cut-off	Do not enter the spa. Check flow, filter, and circulation pump. Water must cool before spa will resume heating.
—	Watchdog — water reached 118°F (48°C); full system disable	Shut off spa breaker. Most commonly a bad temperature sensor, hi-limit sensor, circuit board, topside keypad, or transformer. Call a qualified technician.

Sensor Resistance Quick-Reference (6600-166)

Water Temp	Resistance (Ω)
68.0°F (20°C)	39,000
77.0°F (25°C)	30,000
86.0°F (30°C)	24,270
95.0°F (35°C)	19,740
104.0°F (40°C)	16,149

(Full Spa Builders LX-10 sensor resistance table is included in the factory service document.)

🎯 Ideal Applications

Application	Suitability	Notes
♨️ Jacuzzi J-300 LED J-310 / J-315 (Convertible, with circ)	✅ Direct replacement	2002–2013
♨️ Jacuzzi J-300 LED J-325 (Convertible, with circ)	✅ Direct replacement	2004, 2008–2013
♨️ Sundance 780 Dover	✅ Direct replacement	2014 – 03/2017
♨️ Sundance 780 Solo / Metro / Caprio / Tango (1 pump with circ)	✅ Direct replacement	Verify configuration
♨️ Sweetwater 2-Speed Lagunas	✅ Direct replacement	2003–2004
♨️ Sundance 850E Series (1-pump with circ)	✅ Compatible	2005+ with circ configuration
♨️ Any spa without a circulation pump	❌ Not supported — order 6600-722 instead
♨️ 2-Jet-Pump Jacuzzi J-300 LED models (J-345, J-355, J-365, J-375, J-385)	❌ Not supported — order 6600-726 instead
♨️ 2005–2007 J-325 240V (non-convertible)	❌ Not supported — use 6600-726

This board is designed for:

• Replacing a failed 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, or 6600-226 board
• Restoring heater, jet, circulation, light, and sensor operation on the above spa models
• Upgrading to the latest Rev 3.57+ / 3.61A logic with Smart Logic energy-save

🤔 Frequently Asked Questions

Q: How do I know if the 6600-724 is the right board for my spa? A: Two requirements must BOTH be met: (1) your spa has a dedicated 24-hour circulation pump (a small, quiet pump that runs most or all of the day), and (2) you have only one jet pump. Then verify the part number printed on your existing PCB — if it reads 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, or 6600-226, the 6600-724 is the correct updated replacement.

Q: Is this an OEM board? A: Yes. The 6600-724 is the genuine Sundance®/Jacuzzi® factory replacement board listed in the official Jacuzzi circuit-board history. It is the superseding part for every earlier revision of the LX-10 J-300 LED 1-pump-with-circ family.

Q: My spa does NOT have a circulation pump — will this board work? A: No. This board is the with-circ-pump variant. Spas without a separate 24-hour circulation pump require the 6600-722 instead.

Q: Does this board support 120V or 240V? A: Both. Jumper JP1 pins 1-2 select between 120V / 15A Logic (jumper ON) and 240V / 40A Logic (jumper OFF). This is why the 6600-724 is the correct board for Jacuzzi J-310, J-315, and J-325 “Convertible” models. Always match the jumper to your spa’s actual wired supply voltage.

Q: Do I need a licensed electrician to install this? A: Yes. NEC Article 680 and most local codes require a licensed electrician for any spa / hot-tub electrical work, and a permit is often required depending on jurisdiction. Board installation also requires correct voltage jumper configuration — follow the wiring schematic on the spa-pack cover.

Q: Will my existing topside panel work? A: If your current topside is the original LX-10-compatible LCD panel for your spa model (commonly 2600-321 or 2600-331 for J-300 LED), it will work. Contact Parts4Tubs with your topside part number if unsure.

Q: Can I return it if it doesn’t fix the problem? A: ⚠️ No. Circuit boards are non-returnable — they cannot be resold as new once installed or powered on. Please verify compatibility carefully before purchase. Manufacturer’s warranty still applies in the event of a defective board.

Q: What sensors do I need? A: Temperature sensor 6600-166 (curled-finger connectors) is consistent across all 6600-724 applications. The hi-limit sensor part number varies by spa model — common options are 6600-068 (Sundance) and 6600-144 (Jacuzzi J-300). Always verify by reading the part number on your existing sensor.

Q: Why is the overtemp cut-off 106°F instead of 110°F? A: The 106°F overtemp protection is a feature of the Rev 3.57+ chip shipped with current 6600-724 boards (introduced on 2010+ chips for the J-300 LED family). The older generic LX-10 service documentation shows 110°F, but the logic chip that ships with this part number uses the 106°F trip for J-300 LED applications.

Q: What does “Smart Logic” do? A: On current Rev 3.61A chip shipments, Smart Logic automatically deducts any circulation-pump run time that occurred outside the programmed filter cycle (e.g., during a heat call) from the next day’s filter cycle. This avoids double-running the pump and saves energy.

⭐ Why Choose the 6600-724

• ✅ Genuine OEM Sundance®/Jacuzzi® replacement board
• ✅ Direct supersession for 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, and 6600-226
• ✅ True 120V / 240V convertible design
• ✅ Ships with current Rev 3.57+ logic chip (Rev 3.61A on newer production) with Smart Logic energy-save
• ✅ Half-hour filter cycles, 106°F overtemp, programmable circulation control
• ✅ Updated heater terminals (screw + spade) for broad model coverage
• ✅ Proven Spa Builders LX-10 platform with documented service procedures
• ✅ Full 65°F – 104°F spa temperature range

🤝 Why Buy From Parts4Tubs

• ✅ US-based company with local technical support
• ✅ Fast US shipping
• ✅ Expert advice from spa specialists — we’ll help you match the right board to your spa’s exact configuration
• ✅ Competitive pricing on genuine OEM parts
• ✅ Manufacturer warranty support
• ✅ Matching temperature sensor (6600-166), hi-limit sensor, flow switch, and topside panels in stock
• ✅ Real help matching spa make, model, year, and existing PCB part number

🌟 Summary

The Sundance / Jacuzzi 6600-724 is the current-production LX-10 replacement circuit board for 1-pump hot tubs with a dedicated 24-hour circulation pump. It is the official factory supersession for 6600-086, 6600-286, 6600-044, 6600-085, 6600-208, and 6600-226 — and is the correct board for Jacuzzi J-310 / J-315 / J-325 Convertible models (2002–2013), Sundance 780 Dover, and 2003–2004 Sweetwater Lagunas. True 120V / 240V convertible, Rev 3.57+ logic with programmable circulation, ½-hour filter cycles, 106°F overtemp, and Smart Logic on current shipments. Non-returnable — verify fit before purchase.

Finding and identifying a replacement Hot Tub Circuit Board (PCB)

If you are looking to replace a failed PCB on your Hot Tub’s spa pack, then quite often identifying the part that you need can be the hardest thing.

Firstly, you are looking for a model number on the actual circuit board itself. Having the model or serial of your hot tub is not going to help at this point, you need to find the number on the PCB itself.

Now, with certain brands of PCB, the number of the replacement PCB that you need is not going to match identically the one you are replacing. Why is that I hear you ask?

Well, normally, it is an updated version. This means that it might have updated firmware on the PCB or be a later revision. Normally, this means that the part number would be slightly different. This is usually indicated with a “12345678 -x” at the end of that part number where x indicated a firmware revision.

In some cases, there will be some following letters on the part number of the circuit board, “12345678 -x MAS” this can indicate that the PCB was used for an OEM meaning it was produced for a certain hot tub manufacturer and the letters identify the manufacturer.

This means if you source an original PCB, it will not have the letters, but will in most cases work just fine.

It can be confusing I know!

What if you can’t find a model number?

If you can’t find a model number on the PCB itself, then you need to look for a model number on the spa pack. Normally, there is a sticker on the outside of the spa pack that tells you the current ratings and input voltages etc and this will have a model number.

In general, most spa packs in the USA are manufactured by Balboa, Hydro-Quip, ACC or Gecko. I know I am generalising here, but if you have a spa pack that has the brand of your hot tub on, it will be an OEM so the key is identifying who made the original box.

From there, you can normally find an original PCB that you will be able to switch out.

For example, the Balboa VS (value series) is a very popular spa pack that has been used by multiple hot tub manufacturers under their own brand names. Whatever they have called it, strip it back and it is still a Balboa VS.

Visual Inspection

One of the most important things you can do when you are looking for a replacement is to visually inspect the PCB that you have versus the picture online of the replacement you are considering. They need to look the same even if there are the differences in firmware revisions or OEM part numbers, you should be visually replacing a PCB that looks like the one you have.

Configuring a replacement Hot Tub Circuit Board (PCB)

When you get a new PCB, you are more than likely going to need to configure it. Most PCBs have a number of different modes and setups that the can operate in. For this, you will need to manual or spec sheet to guide you.

For things like DIP switches, most of the time you can copy the settings from your original circuit board. You are looking for things like setting the voltage as a lot of PCBs can be configured to run on both 115V and 230V.

You may need to move jumpers or even wires to configure voltages – the key here is that you read the schematic and don’t expect the PCB to just work out of the box – it usually doesn’t.

Troubleshooting a Hot Tub Circuit Board (PCB)

Here are some common things you will see when you replace a PCB on a hot tub.

You press the buttons on the topside control and they don’t control the right parts (pumps or blower etc) – this is a mode configuration thing and you will either need to change some DIP switches on the PCB or an internal or low level programming mode on the topside control. Check the manual for how to do this.

You turn on the hot tub and it trips the breaker – it is not common for a new PCB to fail out of the box (I have not seen one yet!) However, a common mistake is that the voltage has not been set correctly. If it is set for 115V and then you try and turn it on, the current draw will be a lot more (twice) than expected and the breaker will trip.

To check this, unplug all of your kit – heater, pumps, blower and then turn on the PCB. If it trips with nothing plugged in, usually the voltage is incorrectly set and what is happening is that live current is being sent to the ground – because you have 4 wires into the PCB rather than 3. Current on the ground loop causes the trip. Check the settings to make sure it is configures for 230V.

It might not trip until you physically turn on a pump or a blower. As mentioned, if the pack is set to 115V and your pump is meant for 230V, it will draw twice the current at half the voltage and trip your breaker. Check the manual for info on how to set the voltage.