Five failures account for 80% of spa repair calls. Knowing the short list keeps you from hunting in the wrong part of the cabinet. This is the repair quick-reference for residential portable and in-ground spas.
1. Water leak under the cabinet
The #1 spa call. Source is almost always one of:
- Union fittings on the pump inlet or outlet— loose or dry O-ring. Hand-tight is the right tightness; wrench-tight cracks the threads.
- Heater manifold gaskets— common failure point at 5–7 years.
- Jet body weep— a jet housing that cracked or has a backside O-ring that aged. Usually visible as a steady drip behind that jet.
- Shell crack— rare on acrylic, more common on thermoplastic shells. Requires shell repair, not just a gasket.
Diagnosis: drain water to just below the leak, dry everything, refill slowly, inspect for the fresh drip source. Dye tests help for slow leaks.
2. Pump failures
Spa pumps run hot, wet, and often in confined cabinets with poor ventilation. They fail from:
- Shaft seal failure— water visible weeping from the motor shaft. Fix: rebuild with a seal kit (~$30–$60 parts).
- Bearing noise— grinding or screeching. Fix: usually replace the whole motor; bearings are rarely worth replacing alone on spa pumps.
- Overheat lockout— internal thermal switch trips. Let cool 1 hour and try again; if it trips repeatedly, the motor is failing.
- Capacitor failure— hums without starting. Replace the start capacitor.
3. Heater failures
Electric heating elements fail in two ways:
- Open element— continuity test shows infinite resistance. Replace the element.
- Grounded element— resistance to ground on the element body. GFCI trips on heater call. Replace the element.
Before condemning the element, verify the pressure/flow switch is actually closing. Most “heater is out” calls end at that switch.
4. Electrical / controller issues
- GFCI trips on any start-up— a ground fault in the pump, heater, blower, or wiring. Isolate each component; a megohm meter is the right tool if you have one.
- Controller display black— check breaker, transformer output, and 24V control voltage at the controller. 80% are simple power-supply issues.
- Controller reads “OH” or “HFL” or “FLO”— manufacturer-specific codes, all related to thermal or flow issues. Reference the manual; don't guess.
5. Cover and cabinet damage
- Waterlogged cover— foam has absorbed water. Replace; a waterlogged cover provides almost no insulation and strains the cover lift hardware.
- Cracked cover vinyl— UV damage after 4–6 years. Replace the cover.
- Cabinet panel rot— wet weather and pest intrusion on the wood-based cabinets of older spas. Composite replacement panels are available for most models.
What you usually don't need to replace
- The entire spa. Even a 20-year-old spa can be rebuilt with new pump, heater, topside controls, and cover for about $2,500–$4,000 — vs. $8,000+ for a new unit.
- The shell. Acrylic shells survive multi-decade service; plumbing and equipment fail long before the shell does.
Spa repair is an economic decision as much as a technical one. Before you quote an expensive rebuild, compare total cost-with-labor to a new spa. If the spa is under 10 years old, rebuild almost always wins. If it's over 15, you're fighting gravity.