Find out how to prevent or limit freeze damage if you find your spa not heating and review several tips for prevention. Common problems leading to freeze damage include dirty/expired filter(s), water level too low, circulation pump failure, tripped GFCI causing no power to the spa, or other technical failures such as a bad heating element, temp sensors, pressure and flow switches or a failure on the PC Board. For specific instructions or advice, call the service department at A-1 Pools, or if you live outside of our service area, call your trusted spa service professional.
If all else fails, place a space heater in your spa cabinet. A small space heater is something I think everyone who owns a spa should have on hand, just in case. Placing a small space heater, set on low, inside the spa cabinet, will keep the cabinet area warm enough to prevent freezing indefinitely in most circumstances. Obviously, you need to use common sense, keeping safety in mind, to ensure the heater is not going to start a fire or cause other damage; for example, keep it away from anything it could melt or overheat. At the time of writing this article, a space heater offered at A-1 Pools and at Fleet Farm (Model CZ442E / SKU: 100449904) would work for this purpose. It is a compact size at 6 inches deep X 5.7 inches wide X 10.1 inches tall which helps it fit easier. It is 1,500 watts and will easily heat your spa cabinet. Choose a small ceramic type heater and avoid heaters with sophisticated timers; you simply want to set it on low fan, low/medium temperature and let it maintain that temperature indefinitely. Plug it into a GFCI protected cord or outlet for safety and do not use the spa with the space heater under it. Close the cabinet after placing it inside and check it often until your spa can be repaired or winterized.
DO NOT simply drain your spa. This is most likely the worst thing you can do because simply draining your spa will NOT remove all of the water from your spas plumbing lines, heater and/or pump housings. Smaller amounts of water remaining in these places will freeze more quickly, especially without whatever remaining warmth which may have existed in the spa water prior to draining. Should you choose to drain the spa, it must be fully winterized. All water must be removed from the plumbing and is most commonly done by blowing through the lines until you see water come out of every jet; and then by blowing pool antifreeze through the lines to ensure any remaining water is displaced and/or diluted by the pool antifreeze, ensuring no freeze damage can occur. Professional winterization is offered by the A-1 Pools service department and you may be better off placing a space heater under the spa until the spa can be professionally winterized.
If your spa has power and is running but not heating, it could be a water flow problem. Your spa is designed to monitor proper water flow and shut down the heater for safety if it senses inadequate flow. Water flow can be reduced by dirty/clogged filters, inadequate water levels causing air to be drawn into the pump and/or too many jets in the spa in the closed position. If this occurs, most spas built in the past 15 or so years will display an error code at the spa side control (i.e. FLO, DRY, 3 dots flashing). First, ensure the spa is filled to the proper level and all jets are in the open position. Then shut the spa down and remove the filter(s) from the spa. After ensuring there is nothing floating in the spa that could be sucked into the plumbing (including items such as a chemical dispenser, scum ball, or debris) turn the spa on to run with no filter at all. If the spa begins heating normally again, you probably have a dirty or expired filter; filters should be chemically cleaned often (monthly is a rule of thumb) and replaced annually (not longer than two years). Monitor the spa closely for the next few days to ensure the problem does not reoccur.
Check your spa programming. Many spas have features built into their controls which enable spa owners to set back the water temperature during certain times of days, or even for extended periods of time. Ensure your spa is not somehow in a special mode (i.e. economy or sleep mode) which could cause it to maintain a lower temperature, or maybe even only heat during filter cycles. Also, be sure the temperature is set properly on your control. Some spas have a low temperature range which will make higher temperatures (such as 80 degrees and up) unavailable. Sometimes low level/technician programming can be accidently modified by curios children pushing buttons or by people sitting on the spa control; this may require a technician to reprogram the spa. Also, a button can become stuck on the topside control causing the temp to be turned all the way down; sometimes pushing the button can get it unstuck, but most often the control will need to be replaced (even if it becomes unstuck).
Reset the power to your spa. If your spa has power, but is not heating, or has an error code or something weird displayed on your spa side control (such as “- - - -“ or “HL”) try shutting the power off at your electrical breaker for a few minutes and then power it back on. Sometimes this will reboot the spa and allow it to heat. However, if there is a problem which causes the spa to overheat, a safety switch called the hi-limit will cause the spa to stop heating again once things get too hot. You will need to monitor the water temperature to make sure it does not overheat and/or return to the same not heating status you originally found it in.
If your spa GFCI breaker is tripping, this is most often caused by a short in a failed spa equipment component, but can also be caused by a defective GFCI. You can try resting your GFCI. If it trips right away, you will likely need to call a spa service tech or an electrician depending on if you think the problem is most likely in the spa or in the electrical system leading to the spa. If the GFCI holds until a specific function (pump, heater, blower, ozonator) engages on your spa, and then trips, that component is likely the one with the short in it. Depending on your technical ability, you may choose to disconnect that component from the spa pack and then power the spa back on; if the GFCI does not trip, you have likely identified the failed component; and if it was not the heater or circulation pump, your spa should begin heating again.
Tips to Prevent Hot Tub Freeze Damage
Professionally winterizing your spa is an option you may wish to consider. Speaking for myself, using my spa in the winter is quite enjoyable, and I do so as often as I have an opportunity to. However, if you find that you rarely use your spa in the winter, you should consider having your spa professionally winterized. The money you save on electricity and chemicals will cover the costs of the service. With your spa winterized you will no longer need to perform routine maintenance and will not have to shovel a path to the spa. Should you choose to winterize your spa, for best results, I recommend you do so before the temperatures fall below freezing. Keep your spa filled and running until the technician arrives on site so he/she can verify everything is in working order before winterization.
Maintain clean filter(s) and the proper water level in your spa. Your spa is designed to monitor proper water flow and shut down the heater for safety if it senses inadequate flow. Water flow can be reduced by dirty/clogged filters, inadequate water levels causing air to be drawn into the pump and/or too many jets in the spa in the closed position. If this occurs, most spas built in the past 15 or so years will display an error code at the spa side control (i.e. FLO, DRY, 3 dots flashing). First, ensure the spa is filled to the proper level and all jets are in the open position. Then shut the spa down and remove the filter(s) from the spa. After ensuring there is nothing floating in the spa that could be sucked into the plumbing (including items such as a chemical dispenser, scum ball, or debris) turn the spa on to run with no filter at all. If the spa begins heating normally again, you probably have a dirty or expired filter; filters should be chemically cleaned often (monthly is a rule of thumb) and replaced annually (not longer than two years). Monitor the spa closely for the next few days to ensure the problem does not reoccur.
Keep your water balanced. Chemical damage due to unbalanced water can cause failure in your heater and pump(s). When your spa’s pH, alkalinity and/or calcium hardness are too low, they cause corrosion damage to your heating element and pump seals. Your heating element will eventually trip your GFCI shutting off power to your spa. Your pump will suffer from water spraying into the motor eventually causing pump failure or an electrical short tripping the GFCI shutting off power to your spa. If your spa’s pH, alkalinity and/or calcium hardness are too high, scale can build up in your heater causing eventual failure. Maintain your pH between 7.2 – 7.6, alkalinity from 80-120 and ensure your calcium hardness is at least 200 and if it is much higher, use chemicals to control scaling. A-1 Pools can test your water and recommend best practices.
Keep the temperature turned up. The outside of your cabinet contains the plumbing for your jets and circulation. This area is likely insulated in some way, but is still the most susceptible to the freezing conditions outside. This area is warmed by hot spa water circulating through the plumbing lines and by heat radiating outward from the hot water in the spa. Since water does not typically circulate continuously through all plumbing lines, maintaining the water temperature too low can put your spa in jeopardy; especially if the power to the spa fails or the spa stops heating since a higher water temperature will give you more time to recognize and address any problems. If you turn down the spa temperature due to less usage, instead, consider having the spa professionally winterized during the winter months.
Keep the jets and water features open. In order to allow warm water to flow through all of your plumbing lines, you should keep all jets open when the spa is not being used. Closed jets prevent hot water from running through those plumbing lines. This becomes even more important for features such as water falls that have plumbing lines near the outside top edge of the spa and are most vulnerable to the freezing temperatures. By leaving these open, even just slightly for a slow rate of flow, you allow for hot water to replace the cool water in those plumbing lines when the pumps come on, thereby preventing freeze up in very cold conditions.
Check your spa regularly. Be sure you are checking your spa often. It would be great if you can check it daily, but that may not be possible. Every other day, twice a week, or at least once a week can enable you to identify a problem early making it is easier to prevent freeze damage. During extreme cold, increase the frequency of how often you check your spa. If you find you do not check your spa often in the winter months, consider having it winterized. On the other hand, if like me, you use your spa 3 times a week in the winter, and perform maintenance at least once a week, you are already probably doing a good job monitoring your spa.
Inspect your spa’s equipment at least annually. Unfortunately, most spa owners never, or very rarely, open their spa cabinet to look over the spa equipment. I suggest doing so at least once a year to identify concerns before they become more significant problems. The A-1 Pools service department provides a spa inspection service and will warranty subsequent diagnostic visits for one year following an inspection, assuming any problems found were addressed. Things you can easily look for (use a flashlight and get down low) include: evidence of leaks (active dripping, dampness, calcium scale left behind after water had evaporated), evidence of rodents (droppings, nesting material, chewed cords) and strange or loud noises from spa equipment (such as whining or growling from pumps or blowers). You can also measure the water temperature in the spa and compare to your top side control display to ensure the sensors are working accurately. Also, push your test button on the GFCI breaker to ensure it is working properly. A trained spa technician from A-1 Pools will also test power to your spa, measure amp draws for your spa and equipment components (which will reveal components beginning to fail) in addition to several other inspection items.