Testing a Spa Heater (Balboa, Davey, Gecko, Aeware, Spanet, etc)
⚠️ WARNING:
QUALIFIED PERSONNEL ONLY
Electrical testing of spa or hot tub heaters must only be performed by qualified personnel, such as a licensed electrician or experienced spa technician. Never attempt to test or service spa electrics unless you are trained and authorised to do so. Serious injury or death can occur due to electrocution or incorrect diagnostics.
Disclaimer
This information is provided as a general guide only. It is not a substitute for professional advice. All electrical work must be conducted by a licensed professional. We are not liable for any injury, damage, or death resulting from improper use of this guide.
This guide provides a basic overview of how licensed professionals may test spa heater elements for systems such as Balboa, Davey, Gecko, Aeware, Spanet and others operating on 220–240V AC. Always refer to the specific manufacturer's documentation for precise values and testing procedures.
Understand How the Heater is Activated
Before testing, confirm that all spa safety and flow sensors are functioning correctly. Spa heaters rely on various methods to determine when to activate:
- Dual temperature sensors (inlet vs outlet) (Balboa)
- Pressure switches (Gecko)
- Flow switches
- Vacuum switches
- Optical water sensors (Davey & Spanet)
Initial Flow and Safety Checks
- Ensure the spa is protected by an RCD (Residual Current Device). This is mandatory in all Australian states.
- Remove filters and check for strong pump flow.
- Inspect the impeller for blockages or debris.
- Ensure all valves are open and internals are not stuck.
- Verify water is circulating freely from suction to return.
Visual Inspection (Power Off)
- Turn off all power at the isolator or breaker.
- Inspect heater element terminals for signs of rust, corrosion, cracking, or discolouration.
Live Voltage Test
Licensed electricians only should restore power and use a multimeter to test for voltage:
- Measure AC voltage across the heater terminals — should be 220–240V AC.
- If voltage is present, proceed to current draw testing.
- If no voltage is present, investigate relays, safety switches, or send your system to us for testing.
Amperage Test (Clamp Meter)
Measure the current draw from one heater terminal:
| Heater Size | Expected Amperage |
|---|---|
| 1.0 kW | ~4.3 A |
| 1.5 kW | ~6.5 A |
| 2.0 kW | ~8.7 A |
| 3.0 kW | ~13 A |
| 4.0 kW | ~17 A |
| 5.5 kW | ~24 A |
| 6.0 kW | ~26 A |
Resistance Test (Power Off)
Disconnect the heater wires and measure Ohms across terminals:
| Heater Size | Expected Resistance |
|---|---|
| 1.0 kW | ~52 Ω |
| 1.5 kW | ~35 Ω |
| 2.0 kW | ~26 Ω |
| 3.0 kW | ~17 Ω |
| 4.0 kW | ~13 Ω |
| 5.5 kW | ~9.5 Ω |
| 6.0 kW | ~8.8 Ω |
Other Issues to Consider
- Faulty relays or contactors
- Control board failures
- Sensor or wiring faults
- Power supply interruptions
- Earth leakage or insulation resistance faults (to be tested by an electrician)
Common Causes of Heater Element Failure
- Corrosive water chemistry (e.g. high Bromine, low pH, high Chlorine)
- Calcium buildup and scaling
- Dry firing (operating heater with no flow)
- Ferrobacillus bacterial contamination
- Old age or wear
Need Expert Help?
If you're unsure, send your complete spa control system and touchpad to us for diagnosis and testing:
Heater & Spa Parts
Factory 1 / 10 Industry Blvd
Carrum Downs, VIC 3201
www.heaterandspaparts.com.au
