No heat? No problem!

If you are seeing an error code on your topside panel

This is your first indication. The system is identifying the issue, whether it is a flow problem, sensor fault, or heater-related fault.

You can use our error code guide below to quickly identify the cause:

View Hot Tub Error Codes Guide

Common heating-related codes often point towards flow issues, which are usually straightforward to resolve at home.

Quick checks you can do first

Before assuming a component has failed, run through these basic checks. These solve a large percentage of no-heat issues:

• Check your set temperature - ensure the spa is actually set higher than the current water temperature
• Check the circulation pump is running - you should feel water movement from return jets
• Check your filtration cycle - heating often only occurs during programmed filter cycles
• Check for tripped breakers - reset your RCD or breaker if required
• Restart the spa - power down for a few minutes and restart to clear temporary faults

Flow issues - the most common cause

If your spa is not heating, lack of water flow is the most common reason. Modern systems will not allow the heater to run unless sufficient flow is detected.

You can check and resolve most flow-related problems yourself:

• Dirty or blocked filters - remove and clean your filters thoroughly, or try running the spa briefly without them to test
• Airlocks in the system - this can happen after refilling. Try loosening a union on the pump slightly to release trapped air (only if safe to do so)
• Closed valves - ensure all slice valves are fully open
• Low water level - top up the spa so water sits above all jets and skimmers
• Blocked pipework or debris - check for visible obstructions in the skimmer or intake areas

In many cases, simply cleaning or replacing your filters will restore proper heating.

If there is no error code

When no fault is displayed but the spa is still not heating, the issue is typically within one of the internal components.

At this stage, basic checks have usually been ruled out, and further diagnosis may be required.

Common fault components

• Heater element - can fail over time or become coated with scale
• Temperature or hi-limit sensors - may give incorrect readings and prevent heating
• PCB (control board) - responsible for sending power to the heater

These components are all replaceable, but we recommend proper diagnosis before purchasing parts to avoid unnecessary costs.

Need help?

Do not leave your hot tub unused due to a heating issue. In many cases, the fix is simple and can be done without specialist tools.

If you are unsure what you need, get in touch with our team and we can help identify the problem and point you towards the correct solution.

Any inspection, maintenance or repair involving electrical components should only be carried out by a qualified electrician or suitably trained hot tub technician. Always ensure the power supply is fully isolated before removing covers or accessing internal components. Hydrospares accepts no liability for injury, damage, or loss resulting from improper handling, installation, or unauthorised repair work. If you are unsure at any stage, professional assistance should be sought.