Balboa GS520DZ PCB – Dual Pump Spa Control Board (DISCONTINUED)

Advanced dual pump circuit board for GS520DZ control boxes – compatible with Deluxe VL range topside controls.

⚠️ IMPORTANT: DISCONTINUED PRODUCT

DISCONTINUED BY BALBOA. LAST STOCK AVAILABLE.

This PCB has been discontinued by Balboa and is no longer manufactured. Limited stock may be available while supplies last. Contact Parts4Tubs for current availability and alternative options.

🔌 Product Overview

Balboa GS520DZ PCB is designed for use with the GS520DZ control box, providing essential functions for spa systems including pumps, air blower, heater, and ozone control.

This board features enhanced dual pump capability with Pump 1 (single or dual-speed with optional circulation) and Pump 2 (single-speed or dual-speed), making it ideal for hot tubs requiring maximum jet power and flexibility. Compatible with Deluxe VL range topside controls such as VL801D and VL802D.

✨ Key Features

✅ Dual Pump Support – Pump 1 (single/dual-speed + circ) and Pump 2 (single/dual-speed)

✅ J17 Port – Air blower or single-speed pump (10A quick blow fuse protection)

✅ Air Blower Output – Yes (optional)

✅ Built-in Heater Control – Integrated heater management

✅ Ozone Ready – Ozone generator output included

✅ 12V Lighting – 12V spa light output

✅ M7 Sensor System – M7 sensors (x2)

✅ Deluxe VL Panel Compatible – Works with VL801D, VL802D

✅ Pump 2 Dual-Speed Option – Enhanced flexibility (single OR dual-speed)

🔧 Technical Specifications

Specification	Value
Brand	Balboa
Model / Series	GS
Product Type	PCB
Status	⚠️ DISCONTINUED
Pump 1	Single or dual-speed + optional circulation pump
Pump 2	Single-speed or dual-speed
Pump 3	N/A
Air Blower	Yes (optional)
J17 Port	Air blower or single-speed pump (10A quick blow fuse)
Heater Output	Yes
Ozone Output	Yes
Light Output	12V
Sensors	M7 x 2
Length	280 mm
Width	130 mm
Box Quantity	1 unit per box

✅ Compatibility Guide

Compatible Control Boxes

Control Box	Compatibility
GS520DZ	✅ Direct fit

Compatible Topside Panels

Panel	Range	Compatibility
VL801D	Deluxe VL	✅ Compatible
VL802D	Deluxe VL	✅ Compatible
Deluxe VL range	–	✅ Compatible

⚙️ Board Functions & Controls

Pump Control

Output	Function	Configuration
Pump 1	Main jet pump	Single or dual-speed
Pump 1 Circ	24hr circulation	Optional (with Pump 1)
Pump 2	Secondary jets	Single-speed OR dual-speed
Pump 3	–	N/A (not available)

J17 Port Options

Option	Specification
Air Blower	Optional output
Single-Speed Pump	Alternative option
Fuse Protection	10A quick blow fuse

Additional Outputs

Function	Specification
Air Blower	Yes (optional)
Heater	Yes
Ozone	Yes
Light	12V

Sensor System

Feature	Specification
Sensor Type	M7
Quantity	2

🛠️ Installation Requirements

⚠️ IMPORTANT: Installation should be carried out by a qualified electrician or competent tradesperson.

Pre-Installation Checklist

• [ ] Verify this is a GS520DZ control box
• [ ] Disconnect all power at the isolator/breaker
• [ ] Photograph existing wiring connections
• [ ] Note existing DIP switch settings (if applicable)
• [ ] Allow capacitors to discharge (wait 5 minutes minimum)

J17 Port Note

SPECIAL NOTE: J17 port allows for the connection of either an air blower or another single-speed pump, protected by a 10 AMP quick blow fuse.

⚠️ Safety Warnings

Electrical Safety

• ⚠️ ALWAYS disconnect power before any work
• ⚠️ Installation by qualified electrician or competent tradesperson required
• ⚠️ Verify RCD protection is installed and functioning
• ⚠️ Never operate spa with covers removed from electrical components

Important Notes

• ⚠️ This PCB is designed for GS520DZ control boxes only
• ⚠️ DISCONTINUED – Limited stock available
• ⚠️ Ensure correct board for your control box type
• ⚠️ Faulty installation may result in board damage and void warranty

🎯 Ideal Applications

Application	Suitability	Notes
♨️ GS520DZ Systems	✅ Direct replacement	Primary application

This board is designed for:

• Hot tubs requiring dual pump operation with enhanced Pump 2 flexibility
• Replacing faulty GS520DZ circuit boards
• Systems using Deluxe VL range topside controls (VL801D, VL802D)
• Spas requiring pump, blower, heater, ozone, and 12V lighting control

❓ Frequently Asked Questions

Q: Is this board still available? A: This PCB has been DISCONTINUED by Balboa. Last stock may be available while supplies last. Contact Parts4Tubs for current availability.

Q: How do I know if this board fits my spa? A: This board is designed specifically for GS520DZ control boxes and uses Deluxe VL range topside panels (VL801D, VL802D).

Q: What’s the difference between GS520DZ and GS510DZ? A: The GS520DZ has a dual-speed option for Pump 2 (single OR dual-speed), while GS510DZ has Pump 2 as single-speed only.

Q: What topside panels work with this board? A: Compatible with Deluxe VL range topside controls including VL801D and VL802D.

Q: Does this board have air blower output? A: Yes, optional air blower output is available via the J17 port, protected by a 10A quick blow fuse. The J17 port can also be used for a single-speed pump instead.

Q: What sensors does this board use? A: The board uses M7 sensors (x2).

Q: What are my options if this board is out of stock? A: Contact Parts4Tubs for alternative solutions. Options may include upgrading to a newer control system or sourcing a compatible replacement.

🔄 Alternative Options

Since the GS520DZ PCB is discontinued, consider these alternatives:

• Contact Parts4Tubs – For current stock availability
• GS510DZ PCB (G1553) – If Pump 2 dual-speed is not required (check compatibility)
• Complete System Upgrade – New control box and topside panel

⚠️ Always verify compatibility before ordering any alternative board.

🏆 Why Choose the Balboa GS520DZ PCB

• ✅ Enhanced Pump 2 Flexibility – Single OR dual-speed option
• ✅ Balboa Quality – Trusted brand in spa control systems
• ✅ Flexible J17 Port – Air blower or single-speed pump option (10A fuse)
• ✅ M7 Sensor System – Reliable temperature sensing
• ✅ Deluxe VL Panel Compatible – Works with VL801D, VL802D
• ⚠️ Limited Availability – Last stock while supplies last

🤝 Why Buy From Parts4Tubs

• ✅ UK-based company with local support
• ✅ Fast UK delivery
• ✅ Expert technical advice from spa specialists
• ✅ Competitive pricing
• ✅ Full warranty support
• ✅ Easy returns within 30 days
• ✅ Compatible parts and accessories available
• ✅ Help with identifying correct replacement board or alternatives

✨ Summary

The Balboa GS520DZ PCB is a DISCONTINUED dual pump replacement circuit board for GS520DZ control boxes. This board supports Pump 1 (single or dual-speed with optional circulation pump), Pump 2 with enhanced flexibility (single-speed OR dual-speed), optional air blower or additional single-speed pump via J17 port (10A quick blow fuse protection), heater, ozone, and 12V lighting. Uses M7 sensors (x2). Compatible with Deluxe VL range topside controls including VL801D and VL802D. Dimensions: 280mm × 130mm. Limited stock available – contact Parts4Tubs for availability and alternative options.

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 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.

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.