11 Reasons Why Your Hot Tub Heater Is Not Working (Guide To Fix It)

Why Your Hot Tub Heater Is Not Working

Hot tub heater can fail at anytime, especially when it is not properly managed. Nothing can be frustrating as laying in your spa, ready to lose all the troubles and tension of a difficult day, only to find out that your hot tub can’t provide you with the refreshing hot bath you wanted at that moment.  This can happen to anyone at any time, it all boils down to every hot tub owner knowing the cause of such glitches and how to handle the situation when it does reoccur.

These are the 11 common reasons why hot tub heaters fail to work:

  • Low water flow or water level
  • Thermostat problem
  • The high limit switch problem
  • Hot tub heater element
  • Hot tub water cover 
  • GCFI breaker tripping
  • Wintery season
  • Control panel/board fault 
  • Electrical connection related issues
  • Hot tub heater
  • Filling your hot tub immediately 

While there are many causes attached to a hot tub heater not heating up, it’s better to know that these causes range from minor to major ones. Most times, these faults are minors and can be patched up with simple troubleshooting techniques that will save you both time and money. In this article, we’ll share with you the basic troubleshooting steps that will put you on top of the situation.

Reasons Why Your Heater Is Not Heating Up

When such situations arise, the first thing you want to do is to take a breath, keep your cool and your head in the game so you can get back into your spa as soon as possible and save the extra cash you would give a repairman. Below are basics heater problems, and a walk-through of their troubleshooting steps.

Low Water Flow or Water Level 

This is the major cause of spa’s heater problems. It may result from clogged or damaged filters, closed valves, blocked or pinched pump impellers pipes and jets, and drain covers. Often, this problem may also result from the blockage of the heater’s screen by particles of impurities and other materials. All these impede the flow of water into the spa and result in low water level, making it quite impossible for a heater to heat the water in the hot tub.

Here is how to get it sorted:

  • Check the water level: The first thing to look out for is the water level on the control panel. This step will give you the best angle to begin your work. Messages like “FLO” or “FLC” on the control panel are indicators of a low flow and water level. This condition can be corrected by filling up the hot tub to the right and exact water level. 
  •  Clean your filters: Another issue is that of the filters, which may be clogged by dirt or damaged from use. When in such bad shapes, filters are responsible for restricted water flow and water level regulations. Cleaning your filters twice or more in a month, depending on usage, is a sure way to have steady water flow in your hot tub. Overly clogged or damaged filters should be replaced at once with new ones for a better soaking experience.
  • Check for clogged pipes: The pump, pipes and jets can be a major drawback in getting enough water flow in a spa. And this can be corrected by checking the mouth of the pipes for any clogs or particles or the pump’s priming to allow free passage of water. Most times, sucking the air out of the pump’s airlock valve and finding blocked or broken jet nozzles and seals can also be a sure way to get rid of this problem once and for all.
  • Examine the pressure switch: Checking on the pressure and flow switch can also be a game-changer in some cases when your hot tub heater is not heating up. The pressure switch is connected to the heater tube and can be flipped on if still fixed onto it. However, this can be achieved by using a multimeter to check the pressure switch’s working order, or by simply calling on a professional.

Thermostat Problem 

Most thermostats come in various forms as knobs, dials and typically as just red arrows on a control panel. And are used to increase the heat in a hot tub. Depending on their types, thermostats can be broken, have their cords damaged, or plugged in well. In some cases, the sensor bulb may be faulty due to corrosion. And this may affect the heating up functions of a hot tub heater, making the water cold or warm instead of hot. 

To resolve the issue:

Give a thorough check to the thermostats to ensure they are in good working order and not broken from the inside as they may in cases. Replaced corroded sensor bulbs and broken or damaged thermostats. If your thermostats are the red-arrow type, check if the cord is plugged or damaged, and replace or re-plug them. 

The High Limit Switch Problem 

The high limit switch like the thermostat and the pressure switch is an important component of a hot tub safety circuit. It is responsible for shutting down the Heater to avoid overheating and melting down. The control is calibrated with a preset maximum temperature, enabling the switch to open and break the electric circuit carrying power into the hot tub. When the high limit switch is faulty or has a meltdown, there’s an increased tendency for excessively hot water.

To resolve the issue: 

Check for a trip or damage in the high limit switch. This operation can be carried out with an ohmmeter or amp meter. A faulty or damaged high limit switch can be replaced with a new one. The most important thing to note is there is an increased risk of electrocution in this troubleshooting process. It’s advisable to get a professional electrician’s help if you’re unfamiliar with water and electricity.

Hot Tub Heater Element

hot tub heating elements

The hot tub heater element is placed within the confines of the spa. And burn out easily when there’s not enough water to cool it. Due to their long immersion in water, they may have a scale build-up, which affects their heat up output. This can as well affect the element’s outer casing and give them a cracking outlook. When this happens, it affects the Heater’s functionality, making it a hurdle to heat the water.

To resolve the issue:

Run a test with a test meter to see if the element is within its normal powering limit—that being, 9-12 ohms. When tested and seen bearing toward infinity or the level slowly rising, the element should be replaced. Scale build-up and outer casing cracking can be handled by maintaining the hot tub water overall chemistry. PH increaser can be applied to reduce the hardness of the water. While, running an Alkalinity as low as 70–80ppm can reduce the formation of scale on a heating element. 

Hot Tub Water Cover 

The lack of a well firm, strong Insulated cover top for a hot tub can significantly affect the heating up process. Torn or waterlogged hot tub cover exposed the spa’s heat to the atmosphere and other elements. The lack of a good top affects the Heater’s capability to heat the water in the tub and make the tub retain heat less.

To resolve the issue:

Fix or replace torn, waterlogged, damaged and dropping hot tub covers with a new, firm and trusted one. A hot tub should be well covered and secured with a lid after every use or when not in use. Getting insulated covers not only traps heat within the spa but also guarantees it against elements and other materials. 

GCFI Breaker Tripping

hot tub gcfi breaker

This is one of the major related problems of a hot tub going warm or cold. The GCFI breaker is a plastic knob/switch that forms the basic part of a hot tub’s electrical pack. It flips when there’s an abrupt surge in electricity, hence, causing a break in electricity transmission. These trips, at times, trigger the failure of electricity supply into the spa, thereby making the tub go cold. 

To resolve the issue:

The GCFI breaker is mostly attached to the metal box of a spa’s electrical pack. At times, GCFI breaker trips can be easily solved by fixing the breaker and flipping it back. In cases where it goes beyond this, it’s good to keep the GCFI breaker moisture-free. When rusted or worn out, the GCFI breaker should also be replaced with a new one. 

Wintery Season

Cold, chilly weather may also play a big role in this. When turned off and not winterized in the winter season, the hot tub freezes up easily. Hence, affecting the equipment and its operation, resulting in the Heater not heating up quickly or not working properly.

To resolve the issue:

During cold, winter seasons, hot tubs should be winterized to avoid the adverse effect of the cold weather on the equipment and its other components. Covering the spa with a resilient, well-insulated tub cover may prove effective against such effects. 

Control Panel/Board Fault 

The control panel handles the running and functioning of a spa’s components. And can as well develop a fault along with the printed circuit board (PCB). This fault may bring about such effects as misleading error codes or your hot tub going cold. 

The Control panel on a hot tub indicates many error codes, but here are some are the five common error codes given by the Control panel: 

  • FLO OR FLC: This error code is an indicator of Water flow-related problems and can.
  • OH: This code, unlike the one first discussed, is a clear sign of a high-temperature degree of the water in a hot tub. When seen, it’s advisable to keep off the spa as the scalding water therein may do great damage to the body. 
  • DR or DRY: this, on the one hand, is a clear signal of not enough water or no water is jetting or spurting through the Heater. This occurs when the water level is running low and can trigger a situation Known as the ‘DRY FIRE’, which may damage the heating element due to overheating.
  • COOL OR COLD: this appears on the print circuit board when your hot tub water temp. Drops for as low as 20 to 40 degrees. This can be easily managed by giving the Heater some time to heat up. 
  • SNB OR SNA: the ‘S’ in this code Stands for Sensor, and when it does pop-ups, it indicates the malfunctioning of a sensor. This error code may also indicate a wrong connection between the circuit board and a sensor. Or, it may as well serve as a signal for when the circuit board is fried..

Electrical Connection Related Issues

When oxidized, not tight enough, melted, frayed, or chewed on by rodents, the wires, cords, and plugs attached to a hot tub may slow down or affect the Heater’s capacity to heat the water inside a tub quickly. This may as well cause malfunctioning of the spa’s components. Another electrical hitch may result when the fuse is blown due to an unstable electricity supply or spike.

To sort this:

Regular inspection of wires, cords, plugs, and circuits after use is a good way to avoid this. Proper maintenance and safety practices on a weekly or monthly basis ensure the longevity of these parts and components and easily exposed them when affected in any way. Be on the lookout for a blown fuse, and when identified, try to replace them with new ones. 

Hot Tub Heater 

As with all things, a hot tub heater may eventually have problems. These problems, however, are typically just two—generating little heat or no heat at all. 

They can result from low water flow caused by simple problems like; clogged pumps and dirty filters, which can be easily resolved by cleaning or rechanneling the congested parts. And maybe as simple to fix by just resetting the Heater. However, when it comes to the Heater not heating at all, this may be a fault of the Heater’s element, and you may have to replace the component or the heater assembly as a whole.

Filling your hot tub immediately 

Most times, the heating up glitch may result from recently refilling a tub after a maintenance or cleaning drain. And this may thwart the heating up process and render the Heater useless. 

How to resolve this:

After refilling a hot tub, it’s best to leave for up to twenty-four hours before use. This is because it takes a hot tub to heat up on average close to twelve to eighteen hours. Also, this may vary with seasons. In Winter, it takes longer, while in Sumner shorter for a hot tub to heat up after refilling.

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