🔌 Cal Spas Circuit Board — C2105R1A (ELE09100209) — Cal Spas 2105 Series Spa Control

Get your Cal Spas 2105 Series spa running again with this OEM replacement circuit board.

⚠️ IMPORTANT — PLEASE READ BEFORE ORDERING

• Identify your board by chip number and OEM part number. Look for chip label C2105R1A (or any revision ending in a different letter) on the white sticker on your existing board. The OEM part number ELE09100209 should also appear on the board or the system documentation.
• Non-returnable. Cal Spas circuit boards are non-returnable and cannot be exchanged except under the manufacturer’s warranty terms. Confirm compatibility before ordering.
• Contact Parts4Tubs before ordering. This board has very limited retailer availability. We will verify current stock status and compatibility before your order is placed.
• Do not order by spa model name alone. Cal Spas circuit boards must be identified by chip number and OEM part number — not by the external spa model.

📋 Product Overview

The Cal Spas circuit board with chip number C2105R1A (OEM part number ELE09100209) is a factory-original Cal Spas OEM replacement PCB manufactured by Balboa Water Group. It is designed for Cal Spas systems using the 2105 control platform — a variant within Cal Spas’ 2100-family control system lineup.

This is a legacy Cal Spas OEM board with limited distribution and documentation available. If your existing board shows the chip designation C2105R1A (or any revision ending in a different letter, such as R1B, R1C, etc.), this is the correct factory-matched replacement.

⚠️ Current availability, voltage configuration, heater rating, and pump specifications for this board have not been confirmed from publicly available sources. Contact Parts4Tubs with your spa’s serial number and system label details for full pre-purchase verification.

💫 Key Features

✅ Genuine Cal Spas OEM circuit board — manufactured by Balboa Water Group for Cal Spas 2105 systems
✅ Chip C2105R1A — all revisions of this chip (newer revisions may end with any letter) are covered by this OEM PN
✅ Factory-matched replacement — identical programming to your original board
✅ Manufactured by Balboa Water Group — world’s leading spa control manufacturer
✅ Cal Spas limited warranty — see warranty section below

🔩 Technical Specifications

Specification	Value
Cal Spas OEM Part Number	ELE09100209
Chip Number	C2105R1A (newer revisions may end with any letter)
System Series	Cal Spas 2105
Manufacturer	Balboa Water Group (for Cal Spas)
Input Voltage	Please refer to your spa’s system label or contact Parts4Tubs
Heater Output	Please refer to your spa’s system label or contact Parts4Tubs
Pump Configuration	Please refer to your spa’s system label or contact Parts4Tubs
Warranty	Cal Spas limited warranty — contact Parts4Tubs for terms
Returns	Non-returnable

⚠️ Electrical specifications (voltage, heater kW, pump amp ratings, breaker size) vary by individual spa configuration and have not been confirmed from publicly available sources for this specific board. Always confirm from the system label inside your spa’s equipment enclosure before installation.

🔗 Compatibility Guide

Compatible Spa Systems:

This board is designed for Cal Spas hot tubs equipped with the 2105 control system and displaying chip number C2105R1A on the circuit board.

⚠️ Always verify by chip number (C2105R1A) and OEM part number (ELE09100209). The Balboa 5-digit board number (beginning with “5”) on the white sticker is also a reliable identification tool. Do not order based on spa model name or appearance alone.

How to Identify Your Existing Board:

1. Open the spa equipment compartment
2. Locate the circuit board inside the control box
3. Find the white sticker on or near the board — it will show the chip number (C2105R1A) and/or a 5-digit number starting with “5”
4. Match these numbers to confirm this is the correct replacement

Replaces:

Part Number	Description
ELE09100209	This board (Cal Spas OEM PN)
CALELE09100209	Cal Spas alternate catalog format
C2105R1A	Chip number (all revisions — newer may end with any letter)

---

🛠️ Installation Requirements

⚠️ Installation must be performed by a licensed electrician in compliance with NEC and all applicable local codes.

Pre-Installation Checklist:

• [ ] Confirm chip number on existing board is C2105R1A (or newer revision)
• [ ] Confirm OEM part number ELE09100209 on board or system documentation
• [ ] Note all DIP switch or jumper settings before removal
• [ ] Record your spa’s voltage and electrical configuration from the system label
• [ ] Disconnect all power at the GFCI breaker or disconnect
• [ ] Allow 5 minutes for capacitor discharge after power-off
• [ ] Photograph all wiring connections before removal

Electrical Requirements:

Requirement	Specification
Supply Voltage	Confirm from spa system label — do not assume
GFCI Protection	Class A GFCI required — NEC Article 680
Ground & Bonding	Required — NEC Article 680
Dedicated Circuit	Required
Disconnect Box	Within line of sight, at least 5 ft from spa
Wire Type	Copper conductors only

⚠️ Do not assume voltage. Confirm all electrical specifications from the system label inside your equipment enclosure before ordering or installing.

⚠️ Safety Warnings

• ⚠️ ALWAYS disconnect all power before circuit board work
• ⚠️ Licensed electrician installation required; NEC Article 680 compliance mandatory
• ⚠️ Class A GFCI required; grounding and bonding required per NEC Article 680
• ⚠️ Verify voltage from your system label — do not assume
• ⚠️ Identify by chip number (C2105R1A) — not by spa model name or appearance
• ⚠️ Non-returnable — contact Parts4Tubs to verify compatibility before ordering
• ⚠️ Cal Spas circuit boards are non-returnable items — they cannot be resold to another owner as new

❓ Frequently Asked Questions

Q: How do I confirm this is the correct board for my spa? A: Look on your existing circuit board for the white sticker showing chip number C2105R1A (newer revisions may end with any letter). Also look for a 5-digit number beginning with “5” — this is the Balboa board number. If both match, this is the correct board. Contact Parts4Tubs with these numbers if you need confirmation.

Q: What voltage does this board run on? A: The voltage configuration is not confirmed from publicly available sources for this specific board. Check the system label inside your spa’s equipment compartment, or contact Parts4Tubs with your spa’s serial number for verification before ordering.

Q: Is this board in stock? A: Availability is limited for this legacy Cal Spas OEM board. Contact Parts4Tubs to confirm current stock status before ordering.

Q: What warranty is included? A: Cal Spas circuit boards carry a limited manufacturer’s warranty. Contact Parts4Tubs for current warranty terms applicable to this part.

Q: Can I use another board as a replacement? A: Possibly — some Cal Spas 2100-family boards have overlapping compatibility. Contact Parts4Tubs with your chip number and spa serial number to explore available replacement options if the original ELE09100209 is unavailable.

✅ Why Choose the Cal Spas C2105R1A (ELE09100209)

✅ Genuine Cal Spas OEM board — factory-matched programming for 2105 systems
✅ Covers all chip revisions — C2105R1A and newer letter revisions
✅ Manufactured by Balboa Water Group — industry-leading quality
✅ Non-returnable — Parts4Tubs verifies chip and compatibility before you order

🤝 Why Buy from Parts4Tubs

✅ Fast US shipping
✅ Expert technical advice from Cal Spas specialists
✅ Compatibility and chip verification before ordering
✅ Competitive pricing
✅ Full warranty support

🔌 Summary

The Cal Spas circuit board C2105R1A (ELE09100209) is a factory-original OEM PCB manufactured by Balboa Water Group for Cal Spas 2105 series control systems. Identification must be done by chip number (C2105R1A, newer revisions may end with any letter) and OEM part number (ELE09100209) — not by spa model name alone. Electrical specifications including voltage, heater kW, and pump configuration are specific to your individual spa and should be confirmed from your system label before installation. This board is non-returnable; contact Parts4Tubs to verify current availability and compatibility before placing your order.

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.