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Hot Tub flow errors can present themselves in many different ways depending on the situation and spa equipment manufacturer. In most cases, a flow error will prevent the spa from heating until it is resolved. Asking yourself the following questions will help identify the cause of the flow issue so that it can be resolved, and you can return to enjoying your hot tub.
Q: Why do spas have flow errors?
A: All spas will have some kind of flow-sensor, flow-switch, pressure switch, etc, that communicates with the PC board that the flow is adequate enough to turn on the heater.
Q: Why is this important? Why can’t you bypass it?
A: If there is no flow through the heater, the heater will try to heat and will be running. This can be called “dry-fire” – which will lead to heater failure, and possible PC board damage, among other issues. Note that most hot tub parts manufacturers do not warranty spa heaters against dry fire, since dry fire is caused by another component error – i.e. – the flow switch. So they can’t warranty a heater that failed because of another component.
Q: Have you recently done a drain and fill?
A: If you have recently drained and refilled your spa, there is a high probability that you have an airlock, which is air trapped in the pumps or plumbing. You can try to power cycle your spa, bleed out the air in the affected pump, or remove your filters and force more water through your filter housing area with your hose, among other things.
Q: Have you checked the water level?
A: If the water level is too low, the filter housing area cannot pull water through it as intended, which leads to a flow error. Make sure the water level is adequately above the water area, as instructed by the spa manufacturer.
Q: Have you removed/checked your filters?
A: Clogged and dirty filters are one of the leading causes of flow errors. This is because the pump responsible for heating the spa needs to pull water through the filters. If the filters are clogged, this leads to inadequate flow.
Q: Have you had any work done on the spa recently?
A: If you have, especially on a pump or flow component, check the installation to make sure everything is configured correctly, and that the correct voltages are assigned, especially in cases of a pump installation.
Q: Has the issue happened before?
A: If so, what solved it last time?
Q: Does the pump seem weaker than normal? Or "surging”?
A: If so, this is indicative of a possible airlock, water level issue, a failing pump, a clogged filter, or a voltage issue.
Asking yourself these questions, among others, can help in identifying the cause of the flow-error and help in finding a resolution.