🛁 Balboa ML400 Topside Control Panel – Compatible with All GL Series Control Systems

🌟 The largest ML series panel with 4-button LCD control – universal compatibility with any GL series control box

📋 Product Overview

The Balboa ML400 Topside Control Panel is the flagship 4-button control interface in the ML series, offering the largest panel dimensions for maximum visual impact and comfortable button spacing. Measuring 190.5 mm × 58.4 mm, this panel provides generous proportions ideal for premium spa installations or replacing larger existing topsides.

Featuring a basic LCD display with 3-digit temperature readout, the ML400 delivers clear visibility of spa temperature at a glance. Operating at 12V, this panel supports single pump operation plus 1 auxiliary output, and connects via an 8-pin connector (2 rows of 4 pins) for secure installation.

What sets the ML400 apart is its universal compatibility with any GL series control box, making it the most versatile choice in the ML range. With dedicated buttons for JETS, AUX, TEMP, and LIGHT, this panel provides essential control for everyday spa operation. This model comes complete with the OL-40040 overlay included, providing a ready-to-install solution with a specific, branded overlay.

⭐ Key Features

• ✅ Largest ML Series Panel – 190.5 mm × 58.4 mm for premium appearance
• ✅ Universal GL Compatibility – Works with any GL series control box
• ✅ 4-Button Interface – JETS, AUX, TEMP, and LIGHT controls
• ✅ LCD Display – Basic 3-digit style for clear temperature readout
• ✅ Single Pump Support – Designed for 1 pump systems
• ✅ Auxiliary Output – Dedicated AUX button for blower or additional device
• ✅ 8-Pin Connection – Secure 2 rows of 4 pins connector
• ✅ 12V Operation – Low voltage design for safe operation
• ✅ OL-40040 Overlay – Specific branded overlay included
• ✅ Balboa ML Overlay Compatible – Works with other Balboa ML overlays

🔧 Technical Specifications

Specification	Value
Manufacturer	Balboa
Model	ML400
Model Series	ML
Product Type	Topside Panel
SKU	TS-ML400
Compatible Systems	Any GL Series Control Box
Display Type	LCD
Display Format	Basic 3 Digit Style
Number of Buttons	4
Button Configuration	Jets, Aux, Temp, Light
Maximum Pumps Supported	1
Blower/Auxiliary Outputs	1
Operating Voltage	12V
Dimensions (L × H)	190.5 mm × 58.4 mm
Connection Type	8 Small Plastic Pins (2 Rows of 4)
Overlay Included	✅ Yes (OL-40040)
Overlay Part Number	OL-40040
Overlay Compatibility	Balboa ML Overlays
Status	✅ ACTIVE

🖥️ Display & Controls

Button Configuration:

Button	Function
JETS	Activate/control jet pump
AUX	Control auxiliary device (blower/other)
TEMP	Adjust temperature setpoint
LIGHT	Control spa lighting

Display Features:

Feature	Description
Display Type	LCD
Digit Format	Basic 3 Digit Style
Temperature Display	Current/set water temperature
Visibility	Clear digital readout

Control Capabilities:

Function	Availability
Pump Control	✅ (JETS button – 1 pump)
Aux/Blower Control	✅ (AUX button – 1 output)
Temperature Adjustment	✅ (TEMP button)
Light Control	✅

🔗 Compatibility Guide

This Topside Control is Compatible With:

Control System	Compatibility	Confirmed
GL2000	GL Series	✅
GL8000	GL Series	✅
Any GL Series Control Box	GL Series	✅

Overlay Compatibility:

Overlay	Compatible
OL-40040 (Included)	✅
Other Balboa ML Overlays	✅

NOT Compatible With:

• ❌ GS500, GS501, GS510 series (use VL series panels instead)
• ❌ BP series control systems (use TP series panels instead)
• ❌ VS/GS systems with SZ or DZ suffixes (use VL700/VL800 series instead)

How to Verify Compatibility:

• 📍 Check your existing topside model (ML400 or similar ML series)
• 📍 Confirm your spa pack is a GL series control box
• 📍 Verify the connector type matches (8-pin, 2 rows of 4)
• 📍 Contact Parts4Tubs if you require confirmation

⚠️ Important: The ML400 is designed for GL series control systems. It offers the broadest compatibility within the GL family, working with any GL series control box. It is NOT compatible with GS series systems.

🔄 ML Series Size Comparison

Model	Dimensions	Area	Best For
ML240	133 × 49 mm	6,517 mm²	Compact installations
ML260	178 × 54 mm	9,612 mm²	Medium cutouts
ML400	190.5 × 58.4 mm	11,125 mm²	Largest cutouts, premium look

Choose ML400 when:

• You want the largest ML series panel for premium appearance
• Your existing cutout requires larger panel dimensions
• You prefer maximum button spacing for comfortable operation
• Replacing an existing ML400 panel
• You need universal GL series compatibility

⚙️ Installation Guide

Before Installation:

• ⚠️ Disconnect power to spa at the isolator/breaker before any work
• ⚠️ Verify compatibility with your spa pack system (must be GL series)
• ⚠️ Confirm connector type matches (8-pin, 2 rows of 4)
• ⚠️ Verify panel dimensions suit your cutout (190.5 mm × 58.4 mm)

Installation Steps:

1. Turn off power at the isolator/breaker
2. Remove the existing topside panel from the mounting location
3. Disconnect the 8-pin connector from the spa pack
4. Connect the new ML400’s 8-pin connector to the spa pack
5. Mount the new topside panel in position (OL-40040 overlay is pre-fitted)
6. Restore power and test all functions

Mounting Information:

Specification	Detail
Panel Dimensions	190.5 mm × 58.4 mm
Profile	Largest ML format
Overlay	OL-40040 included and fitted
Connection	8 small plastic pins (2 rows of 4)

⚠️ Professional installation recommended if you are unfamiliar with spa electronics.

⚡ Wiring & Connection

Connector Information:

Specification	Detail
Connector Type	8 Small Plastic Pins
Pin Configuration	2 Rows of 4 Pins
Operating Voltage	12V

Connection Location:

The ML400 connects to the topside port on any GL series control box via an 8-pin connector arranged in 2 rows of 4 pins.

⚠️ Never force the connector. Ensure correct alignment of the 8-pin connector before insertion. If it doesn’t fit, verify compatibility with your control system.

🔍 Troubleshooting

Common Issues:

Problem	Possible Cause	Solution
Blank display	No power or loose connection	Check power supply and reseat 8-pin connector
Error codes displayed	Various system issues	Refer to spa pack manual for error meanings
Buttons unresponsive	Overlay wear or panel fault	Check overlay condition
Incorrect readings	Temperature sensor issue	Check temperature sensor (separate component)
Display dim or flickering	Connection issue or power problem	Check and reseat 8-pin connector
JETS not working	Pump issue	Check pump connections and spa pack configuration
AUX not responding	Auxiliary device or wiring issue	Check auxiliary device connections
TEMP button not responding	Panel fault	Check button membrane condition

Error Codes:

Error codes are determined by the spa pack, not the topside panel itself. The ML400 displays error information from your GL series control system. Refer to your spa pack manual for specific error code meanings.

🧹 Maintenance & Care

Routine Care:

Task	Frequency
Wipe with soft damp cloth	Weekly
Check button response	Monthly
Inspect cable connection	Annually
Check overlay condition	Annually

DO NOT:

• ❌ Use abrasive cleaners or scouring pads
• ❌ Submerge the panel in water
• ❌ Use solvent-based or chemical cleaners
• ❌ Press buttons with sharp objects
• ❌ Force or bend the 8-pin connector

Overlay Replacement:

The ML400 uses the OL-40040 overlay and is also compatible with other Balboa ML overlays. If the overlay becomes worn, faded, or buttons become unresponsive, replacement overlays are available separately.

🎯 Ideal Applications

Application	Suitability
🔄 Replacement for faulty ML400 topside	✅ Ideal
🎛️ Spas with any GL series control box	✅ Compatible
♨️ Single pump spa systems	✅ Ideal
📐 Large cutout installations	✅ Ideal
⭐ Premium spa installations	✅ Ideal
🔘 Simple spa control requirements	✅ Ideal

Common Replacement Scenarios:

• 💔 Cracked or damaged display
• 🔘 Unresponsive buttons
• 💧 Water damage to existing panel
• 👁️ Faded or dim display
• 🔌 Damaged 8-pin connector
• 🏷️ Worn or illegible overlay (OL-40040)

❓ Frequently Asked Questions

Q: How do I know if this topside is compatible with my spa?

A: The ML400 is designed for any GL series control box. Check your spa pack to confirm it is a GL series system. This panel is NOT compatible with GS series systems.

Q: What is the difference between ML240, ML260, and ML400?

A: The main difference is size. ML240 (133 × 49 mm) is compact, ML260 (178 × 54 mm) is medium, and ML400 (190.5 × 58.4 mm) is the largest. All have the same 4-button configuration and LCD display. ML400 also has universal GL series compatibility.

Q: What GL series control boxes is this compatible with?

A: The ML400 is compatible with any GL series control box, including GL2000, GL8000, and other GL variants. This makes it the most versatile ML series panel.

Q: What overlay is included?

A: The ML400 comes with the OL-40040 overlay included. It is also compatible with other Balboa ML overlays if you wish to change the appearance.

Q: What is the difference between ML and VL series panels?

A: ML series panels (like ML400) are designed for GL series control systems and use 8-pin connectors. VL series panels are designed for GS/VS series control systems and typically use telephone cord style connectors. They are NOT interchangeable.

Q: What does the AUX button control?

A: The AUX button controls the auxiliary output on your spa, which is typically connected to a blower or other auxiliary device. Refer to your spa pack documentation for specific AUX configuration.

Q: What are the dimensions?

A: The ML400 measures 190.5 mm (length) × 58.4 mm (height), making it the largest panel in the ML series.

Q: Is this product currently available?

A: Yes, the ML400 (TS-ML400) is an active product and currently available for order.

🏆 Why Choose the Balboa ML400

• ✅ Largest ML Series Panel – 190.5 × 58.4 mm for premium appearance
• ✅ Universal GL Compatibility – Works with any GL series control box
• ✅ Genuine Balboa Quality – Manufactured to Balboa’s exacting standards
• ✅ Simple 4-Button Design – JETS, AUX, TEMP, LIGHT for essential control
• ✅ LCD Display – Basic 3-digit style for clear temperature readout
• ✅ Branded Overlay – OL-40040 overlay included
• ✅ Secure 8-Pin Connection – Reliable 2 rows of 4 pins connector
• ✅ 12V Operation – Safe low voltage design
• ✅ Currently Available – Active product in stock

🤝 Why Buy from Parts4Tubs

• ✅ UK-based company with local support
• ✅ Fast UK delivery
• ✅ Expert advice from spa specialists
• ✅ GL series compatibility assistance
• ✅ Full warranty support
• ✅ Easy returns within 30 days
• ✅ Replacement OL-40040 overlays available

✨ Summary

The Balboa ML400 Topside Control Panel is the largest 4-button control interface in the ML series, designed for premium spa installations with any GL series control box. Measuring 190.5 mm × 58.4 mm with an LCD display showing basic 3-digit temperature readout, this panel provides control of JETS, AUX, TEMP, and LIGHT functions with maximum button spacing. Supporting 1 pump and 1 auxiliary output, this panel connects via an 8-pin connector (2 rows of 4 pins) for secure installation. The branded OL-40040 overlay is included for a ready-to-install solution. Order from Parts4Tubs for fast UK delivery and expert support.

Balboa BP Spa Packs

If you have a “BP” spa pack, you will find the name and model on the label, then you can use any of the “TP” range of topside controls, TP400, TP600 etc etc.

 

You can also use any of the “Spa Touch” graphical controllers on your Spa Pack. Spa Touch comes in versions 1-3 with 4 to be released very soon as well as the new “mini”.

 

The BP Spa Pack made things nice and easy so when you are replacing your topside control with one of these, it is straight forward enough.

 

Balboa VS & GS Spa Packs.

 

If you have an older hot tub that you are keeping alive with new parts, then the chances are you have an older spa pack in there too. This is where it gets a little more complicated in terms of compatibility.

 

Two of the popular models are the VS which stands for Value Series and was supplied to a lot of OEMs (manufacturers for hot tubs) to go into their tubs. Likewise, the GS (global series) was the same. Lots of different rebranded options, different names, but at the heart of things are these two packs.

 

What is key on these two models, is the combination of letters and numbers that make up the model number on the Spa Pack.

 

The VL range of topside controls was designed for both of these spa pack ranges; however, there are some “rules” we need to abide by in terms of compatibility.

 

VL Panels ending in D work with VS/GS systems ending in DZ

VL Panels ending in S work with VS/GS systems ending in SZ

The rest of the VL Panels work with VS/GS systems ending in Z (not SZ or DZ)

 

For example, a Spa Pack model VS501SZ would work nicely with a Topside that is model VL620S. However, that same topside control would not work with a spa pack model VS501Z. The connections are the same, it would plug in, but would not respond at all.

 

Another example, a Balboa GS500Z spa pack would work with the VL406T or the VL401 but would not work with the VL702S.

 

You get the patters. Topside ends in S or D, matches to Spa Pack ending in SZ (for S) or DZ (for D).

 

 

Balboa EL & GL Spa Packs

 

Before the birth of the BP range, the EL and GL Spa Packs did have some level of standardisation in terms of the topside controls.

 

All of the “ML” range of Balboa Topside Controls are designed to work with the EL and GL range of spa packs. They actually look very similar to the TP range, they just have a different type of connection to plug into the Spa Pack.