Spa Pack and Topside Error Codes: The Basics

When a hot tub stops heating or a code starts flashing on the topside panel, the spa's control system is telling you what it sensed. Most codes point to a water flow, temperature, or sensor problem, not a failed control board. This guide explains the codes you're most likely to see on Balboa and Gecko systems, which checks owners can safely make, and when the spa pack or topside actually needs replacing.

Safety first: Hot tubs combine water and high-voltage power. Before opening the equipment compartment, removing panels, or touching any wiring, turn off power at the breaker or GFCI disconnect. Don't bypass sensors, high limits, or flow switches. Testing and replacing parts inside the control box should be done by a qualified spa technician or electrician. If the display warns that the water is too hot, stay out of the spa until it cools.

First: identify your control system

Codes differ between manufacturers and even between models from the same manufacturer. Look on the control box (the spa pack) in the equipment area for a label naming the brand, such as Balboa or Gecko, and the model. The topside panel may also show the brand. Your spa's owner's manual or the control maker's website will have a code list for your exact system. The tables below are general guides only.

Common Balboa messages

Balboa systems vary by generation, and newer panels may show full text messages instead of short codes.

• FLO, LF, or flow messages: the system isn't detecting enough water flow, or the pressure or flow switch isn't working correctly.
• HFL or HL: the two temperature sensors are reading very different temperatures, which often means low flow through the heater.
• dr or dry: the heater may have too little water or air in it. A repeated dry message can lock out heating until it's reset.
• OH, OHH, or HH: overheat. The water or the heater has reached a safety limit, and the spa may shut down. Low flow is a common cause.
• SnA, SnB, Sn, or SnS: a temperature sensor isn't working or the sensors don't agree. Check sensor plugs for a loose connection or corrosion before replacing anything.
• ICE: freeze protection is active because the system detected a possible freeze condition. Pumps may run on their own; this is normal.

Common Gecko messages

• FLO: no water flow detected while the main pump is running.
• OH: spa water temperature is too high. Don't use the spa until it cools.
• HL: the heater's high-limit protection has tripped because of high temperature in the heater.
• Prr: problem with the regulation (temperature) probe.

Flow checks to do first

Most heating and temperature codes trace back to water flow. With power off where needed, check:

1. Water level: make sure it's above the skimmer opening and any suction fittings.
2. Filter: remove the filter cartridge and run the spa briefly without it, if your manual allows. If the code clears, clean or replace the cartridge. Shop Filter Cartridges.
3. Valves: make sure slice or gate valves in the equipment area are fully open.
4. Jets: open any jets that have been closed. Too many closed jets restricts flow.
5. Air lock: after draining and refilling, air can get trapped in the pump. Your manual will explain how to bleed it, often by loosening a pump union briefly until water appears, then retightening.
6. Suction covers and skimmer: clear leaves, hair, or debris blocking intakes.
7. Circulation pump: on spas with a separate circulation pump, make sure it's running.

After fixing a flow problem, reset the code following your manual. Many systems need a power cycle at the breaker, or a button press, to clear a lockout.

When it's a parts problem

If flow is good and the code keeps coming back, a technician can test the likely parts:

• Temperature or high-limit sensors: often replaceable without changing the whole pack.
• Pressure or flow switch: can fail or need adjustment.
• Heater element or heater assembly: a failed element can stop heating or trip the GFCI.
• Circuit board: replacement boards must match the spa pack model and sometimes the software version.
• Topside panel: a cracked overlay, water inside the panel, or unresponsive buttons with a working pack points to the topside. Replacement topsides must be compatible with your control system.

Shop spa packs, topsides, and control parts in Spa Packs & Topside Controls, or browse by brand: Balboa Water Group, Gecko Alliance, and Hydro-Quip. Jets and other spa parts are in Spa & Hot Tub Parts.

Tips for ordering the right spa part

• Photograph the label on the spa pack and the part number on the circuit board, if visible.
• Note the topside's model or part number from the sticker on the back.
• Note your spa's voltage and service (for example, 120V or 240V) from the pack label.
• When replacing a whole pack, also confirm the number and type of pumps, blower, lights, and heater size it needs to run.

Seeing a code that isn't listed here? Use the chat on this page or reach us through our contact page with your spa pack model and the code, and we'll help you find the part you need.