Find out more about the most common hot tub repairs and how to avoid them. The Hot Tub Engineer provides hot tub repairs throughout Maidstone, Kent and across England.
Below we look at common hot tub problems, from not heating up properly to jets not working, and explain the simple checks that can prevent small issues from becoming costly repairs.
Why Hot Tub Maintenance Matters
Most common hot tub problems start with the water. When water chemistry drifts even a little, components work harder, heat control becomes erratic, bacteria and algae begin to grow, and parts like pumps, heaters and filters wear out faster.
Regular maintenance keeps the spa running smoothly, protects the tub’s shell and plumbing, and saves money over the years by reducing avoidable repairs. Make sure you test and balance the water every week and after heavy use, because a couple of weeks without attention is enough for cloudy water and smells to appear.
Water Chemistry: The Foundation for Fewer Repairs
Proper water chemistry protects every part of the system. Keep pH in the safe range, maintain total alkalinity, and use the right level of chlorine or bromine for your spa. When pH is low, the heater and heating element can corrode; when it’s high, scale forms on the element and in the pipes, restricting water flow and making the pump and heater run longer to achieve set heat.
Shock the hot tub after parties, during warm weather, and any time water looks dull, as body oils, lotions and cosmetics create a film that reduces sanitizer effectiveness. If you notice persistent odour or slimy surfaces, drain, deep clean the shell and jets, flush the plumbing to remove biofilm, and refill with fresh hot tub water before bringing chemistry back to normal.
Filters: Small Parts, Big Impact
Dirty or old filters are behind many common hot tub problems. A clogged filter reduces water circulation, triggers FLO error codes on the control panel, and can even cause the breaker to trip as components strain to run.
Rinse filters with clean water every week, use a proper filter-cleaning solution every few weeks to remove oils and dirt, and replace the filter cartridges on schedule for your model. If you suspect a water flow issue, remove the filter temporarily and run the spa for a few minutes to see whether circulation improves, just make sure no debris can be drawn into the housing while the filter is out.
Heating Problems: Element, Flow, or Settings?
Hot tub heater issues are frequent but often straightforward to resolve. There are usually two potential causes: a problem with the heating element, or a problem with water flow. Low pH leads to heater damage over time, while scale or a blocked filter reduces water flow across the element and triggers DRY, COOL or OH error codes.
Check the filter first, then confirm the circulation pump is running, the air valves are set correctly, and the control panel set-point hasn’t been changed. Older spas sometimes run a pre-heat programme at certain times of day; review your control system guide and make sure the schedule matches your needs so pumps aren’t running unnecessarily and transferring excess heat to the water.
Hot Tub Leaks: Find the Source Before You Fix
If you suspect your hot tub is leaking, turn the spa off at the breaker to protect the system. Most leaks occur at unions, seals and gaskets around pumps, heaters and jets rather than in the tub’s shell. Start by checking all visible connections, including the pipes and jets. The circulation pump is a common source; examine the pump seal and housing.
If the drop seems to come from the heater, inspect the pressure switch, unions and element manifold before assuming the heater needs to be replaced. Some spas include shut-off valves on either side of the pump to avoid draining the tub during a repair; other valve bodies are clamped with a gasket between them, and that gasket can fail and lead to leaks.
Always purchase the correct replacement parts for your spa brand, as different spas use different gaskets and seal sizes. If you discover a leak in an air control valve, replace it promptly to prevent water ingress into controls and electronics.
Pump Problems: Noise, Airlocks and Low Flow
When pumps start to squeal, the bearings are usually worn and the unit is approaching the end of its working life. A deep grumbling noise suggests the pump is starved of water, which can be caused by a low water level, closed valves, or an obstruction in the filter or suction.
Make sure water is up to the recommended line, open any isolation valves fully, and remove debris from the skimmer and intake areas. If the pump hums but won’t start, check that the impeller is free and that the capacitor is intact.
Airlocks are common after a drain and refill; loosen the pump unions until a trickle of water appears and then retighten, or cycle the pumps on and off a few times to purge trapped air. Priming the system correctly after maintenance helps avoid recurring low-flow issues that can lead to heater faults.
Jets Not Working: Simple Checks Before a Repair
If the jets aren’t working, make sure the filter is clean and seated properly, because restricted water circulation is a key cause. Confirm the diverter valves are open and not stuck.
Airlocks can also prevent jets from starting; bleeding the pump unions as above often restores normal operation. Inspect the jet faces and nozzles for scale and dirt, as build-up reduces performance and may eventually cause leaks around the fittings if left in place.
Breaker Tripping and GFCI Checks
A Ground Fault Circuit Interrupter protects you by cutting power if it detects an electrical issue. Sensitive by design, a GFCI can trip from moisture in the control box, a shorted heating element, a failing pump, or even a damaged cable to the control panel.
Before you reset, make sure the area is dry, check for obvious damage, and verify that water chemistry and filtration are correct, because low flow can cause components to overheat and trip the breaker. If the spa trips again immediately, contact a registered professional or a qualified electrician, as repeated resets can mask a deeper problem and lead to further damage.
Cloudy, Dirty or Smelly Water
Cloudy water, foam and odours are signs the sanitizer is depleted or the water is saturated with contaminants. Test pH, alkalinity and sanitizer with fresh test strips and adjust as needed. Shock the water to break down oils and organic waste, and run the system to circulate chemicals through the pipes and jets.
If clarity doesn’t return quickly, drain, clean the shell, spray into jet bodies and fittings to remove hidden dirt, and refill. Don’t forget the spa cover: a dirty cover harbours algae and bacteria, drips debris back into the tub, and can make the water look dull. Wash the cover with a suitable cleaner, rinse thoroughly, leave it open to dry, and treat the vinyl to protect it from UV damage.
Covers, Cabinets and Protecting Exterior Parts
Your cover does more than keep leaves out. It reduces heat loss, protects water chemistry from rain and airborne dirt, and keeps the spa safe when not in use. A damaged, water-logged cover forces the heater to run longer, raises electricity use and can lead to heating complaints that are not truly heater faults.
Inspect stitching, hinges and seals, clean both sides regularly, and replace a heavy or sagging cover to maintain efficiency. Wipe cabinet panels to remove grime and algae, especially around the base where splash-back and puddles keep surfaces wet.
Pipes, Seals and Cold-Weather Protection
Pipes and seals shrink slightly in winter, which can reveal minor leaks that aren’t obvious in summer. Keeping the spa running during cold snaps, even on a low heat, helps protect components from freeze damage.
If you need to shut down for a few weeks, winterise properly by draining, blowing out lines, and leaving valves open so trapped water can’t expand and split fittings. Skipping this step is a common source of springtime hot tub repairs.
Control Panels, Sensors and Error Codes
Modern control systems display error codes to help you find the source of a problem. FLO points to a pressure or water flow issue, OH indicates overheating risk, DRY shows insufficient water through the heater, COOL confirms water is below the recommended range, and SNA or SNB means a sensor in socket A or B isn’t communicating.
Make sure you have good water circulation, confirm valves are open, clean the filter, and check for airlocks. If codes persist after those checks, the pressure switch, temperature sensors or board may need testing and, if required, replacement by a professional.
Swim Spas and Larger Systems
Swim spas share the same core components as hot tubs but move much more water through larger pumps and additional jets. The same principles apply, such as clean filters, balanced water, clear circulation paths, but bigger systems magnify small problems.
A partially blocked filter can lead to significant heat loss and visible performance drops, so increase inspection frequency if you run strong current settings or use the system for daily workouts.
Setting a Simple Maintenance Routine
A simple, regular maintenance routine is the best way to avoid hot tub repairs. Test the water a couple of times each week, rinse the filters weekly, and schedule a deep clean every few weeks depending on bather load.
Keep a small log on your phone or website dashboard so you can spot patterns, for example, if you notice the tub takes longer to reach set heat, for example, you can investigate water flow and filter condition before a larger issue occurs. Small habits like showering before a soak and limiting oils or cosmetics make a noticeable difference in keeping the spa clean.
When to Call a Professional
DIY checks help you find the source of a problem quickly, but certain repairs, particularly those involving the control panel, heating element wiring, or persistent leaks inside the cabinet, are best handled by a registered, experienced spa engineer. If you’ve tried the simple steps above and the issue returns, or if the breaker trips repeatedly, it’s time to get professional advice. Prompt attention prevents further component damage and protects your warranty rights.
Need Help in Maidstone, Kent or Across England?
If you’re struggling with hot tub maintenance or you’ve discovered a leak, low heat, error code or water circulation problem, The Hot Tub Engineer can inspect, diagnose and resolve the issue quickly. We work on all major brands and can replace filters, pumps, heaters and control system parts to get you back up and running.
For friendly advice, information about common problems, or to book a repair, contact us today, call, email, or use the contact us form and we’ll help you keep your spa clean, safe and working perfectly for years.
At The Hot Tub Engineer, I provide expert-level services for hot tubs, swim spas, and pools in and around Maidstone, Kent. I can carry out yearly servicing appointments, as well as cleaning sessions, general maintenance, installations, and more.
