Balboa GS100 Control Pack – Heating Issues Overview
The Balboa GS 100 is a compact control system commonly found in Chinese-imported spas, often those sold under the now defunct Spas Direct brand. It’s a basic system often paired with a small heater and simple keypad. This is a troubleshooting and diagnostic information page regarding these systems.
Warning: Any diagnostics should be performed by a qualified person only, such as a licensed electrician experienced with diagnostics. This is not DIY work!
Common Heating Problems
We frequently see heati.ng issues with the GS100, particularly as the unit ages or if it’s been incorrectly installed. One of the first things you notice is the spa may only reach to around 27-32°C. You will need a qualified person to test for the following:
Heater Relay Intermittent Fault - A common issue is relay failure on the circuit board. The heater may attempt to run for a short time (30–60 seconds), then shut off—often without showing an error code. This usually means the relay isn’t properly delivering power to the heater.
No Power to the Heater - If the system appears to be heating but the heater terminals aren’t receiving 240V, the heater relays are likely burnt, stuck, or failed. In many cases, the board may show scorch marks or visible damage.
Heater Failed - The first step in a heater is to ensure it's receiving the 240V consistently. Often when a heater fails, it will trip a circuit breaker, leak, or have other symptoms. Also check the resistance across the terminals (with it disconnected from the control box. It should measure ~26Ω on 2kw heaters, and approx ~17Ω on 3kw heaters. Your electrician should also test for earth-leakage with a special tester. If the heater does not pass earth-leakage, is shorting, or shows resistance not similar to above, you may have a heater fault.
Flow or Sensor Issues - The GS100 uses Balboa’s M7 sensor system, which depends on correct water flow. Blocked filters, undersized pumps, or airlocks can prevent heating, though this typically triggers an error code such as "Sn" or "OH".
Repair or Replace Options
If you’re experiencing heating problems with a GS100 system, you have two main options:
1. Send It to Us for Assessment & Repair - We offer expert diagnosis and repair services for GS100 control boxes. Visit: https://heaterandspaparts.com.au/pages/repairs
2. Buy a New Control Box or Heater - We stock a full range of replacement GS100 control boxes and compatible heaters. Links: Control Box | Heater