Standout from competitors by mastering drop-in hot tub installations

June 19, 2016

By Dave Hoffman

When discussing pool design options with clients it is important to sell the many benefits of having a hot tub attached to, or side-by-side with their pool.

Hot tubs continue to be an important element for consumers when it comes to creating their backyard oasis. However, builders have not always been quick to capitalize on the benefits of marketing hot tubs when selling pools. Most tend to leave the selling of stand-alone hot tubs to outdoor living retailers, which also offer backyard furniture and other similar accessories. That said, by embracing hot tubs, whereby making them an integral part of a backyard pool design, builders are better able to distinguish their business from their competition. By adding a drop-in hot tub with the pool, builders can increase their profits on pool projects, while their clients get more enjoyment out of their backyard oasis.

Benefits of drop-in hot tubs

When discussing pool design options with clients it is important to sell the many benefits of having a hot tub attached to, or side-by-side with their pool. For instance, a popular trend today is integrating an outdoor kitchen and dining area nearby the pool and hot tub.

If the hot tub and pool are positioned too far from one another, the ability to create a cohesive outdoor living space can become hard to achieve.

One of the most obvious benefits of an adjacent hot tub is the fact parents can easily relax and enjoy the hydrotherapy benefits of the hot tub while supervising their kids swimming in the pool. In some cases, standalone units, which are positioned too far from the pool area, are not truly integrated into the backyard.

Another benefit is ease of maintenance, as drop-in hot tubs require less upkeep than a standalone unit because the former uses the pool’s pump and filtration system, which also makes water chemistry easier. Waterfall (spill-over) hot tubs are further integrated into the pool, as the plumbing system must be designed to allow the water to circulate from the pool to the hot tub and vice versa.

Further, the pool water circulating into the hot tub is already 26.6 C (80 F) so it should only take an additional five minutes to heat the water to a comfortable 40 C (104 F) for hot tub bathing. As most pools are equipped with a heater that is sized for the pool, it makes heating the water much easier and more efficient than having a separate hot tub.

Finally, a drop-in spill-over hot tub also fills the need for those clients who also want a water feature or fountain effect in their backyard. The water spilling over from the hot tub to the pool provides the sounds of cascading water that many clients want as part of their backyard oasis.

How to incorporate drop-in hot tubs into the backyard

A drop-in spill-over hot tub also fills the need for those clients who want a water feature effect in their backyard.

Builders that have not planned and/or installed a pool with a drop-in hot tub should consider getting design assistance from the manufacturer when it comes to configuring the homeowner’s backyard, just to make sure everything goes as planned.

Essentially, the hot tub can be placed anywhere in the backyard but, ideally, the pump should be kept as close as possible—no more than 9.1 m (30 ft) away from the hot tub. The best range is no more than 7.6 m (25 ft).

The main reason for installing the equipment nearby is to ensure proper water pressure for the hot tub jets. Most hot tubs allow bathers to adjust the jets in one or two seats; however, if all 25 jets are open, and the equipment is located more than 7.6 m away, the hot tub might not provide the powerful hydrotherapy jet action the client is expecting.

With variable-speed pumps (VSPs) now an option, their quiet, energy-efficient operation makes it easier to install equipment closer to the pool and hot tub as disruption is minimized.

Building pools with drop-in hot tubs

When installing the hot tub in the ground next to the pool it is important to pay special attention to the soil composition around the construction site. Ideally, the soil should be sandy, as this will allow water to drain properly. If the ground has a hard clay-like composition, water will not be able to drain properly, thus getting caught under the hot tub, and potentially cause the unit to float and lift out of the ground. Therefore, to be safe, it is important to install a drain under the unit.

One benefit of an adjacent hot tub is the fact parents can enjoy hydrotherapy while supervising their kids in the pool.

“We always install a drain on all drop-in hot tubs we install, just to be safe,” says Paul Perciballi, owner of Perciballi Pools in Windsor, Ont. “We have been building pools with drop-in hot tubs since 1973 and we know there are many things that cannot be prevented or predicted.

“For example, in our area, the sewers and drains often get clogged in the spring after the winter ice melts. It not only floods basements, it can also lift empty hot tubs.”

In this regard, it is also important the drop-in hot tub itself is completely supported under the unit’s footwell. The unit should never be supported by the hot tub lip, as it is not designed to sustain any weight. Should a hot tub be supported in this fashion, the lip will flare and crack.

Two-pool mentality

When installing a drop-in hot tub next to the pool, pay special attention to the soil composition. It should be sandy to allow for proper water drainage.

Working with a drop-in hot tub is the equivalent of building two pools side-by-side. Once builders start thinking in this manner, drop-in hot tub installation projects become much easier to tackle—especially from a plumbing perspective.

Plumbing a pool system with a drop-in hot tub does not change the original equipment pad design; it only incorporates the addition of two three-way valves. The first valve is installed in front of the pump to control suction from the pool or hot tub, while the second valve is installed after the heater
to divert water to either the pool or the hot tub.

When installing a spill-over hot tub and pool combination, an inline check valve must be installed in the return line going to the hot tub. This check valve will prevent the backflow of water from the hot tub to the pool. Because the spill-over hot tub sits higher than the pool, this backflow will occur when the system is shutdown as pool water is running the waterfall (spill-over).

If the drop-in hot tub has no more than 12 jets, only one pump is typically required. However, if the unit is a spill-over model with 25 jets, for example, a second booster pump should be installed. These pre-plumbed drop-in hot tub shells typically have two, 51 mm (2 in.) suction and return lines. The suction line attached to the skimmer canister in the hot tub must be connected to the suction side of the booster pump. The return water from the booster pump needs to connect to the diverter valve side of the hot tub. This plumbing configuration will allow water from both pumps to be filtered. It also gives maximum water flow with less restriction to the side of the hot tub with the most jets.

The three-port valve is often used when a pool and hot tub share one filter, heater, and pump. In this situation, the water is alternately diverted to the pool or hot tub. Three-port valves are shaped like a ‘Y’ or a ‘T’ and are used in drop-in hot tubs to divert air bubbles and jet water to one side or the other, or a combination of both. The design of three-port valves is such that water flows from one direction and then divided into a choice of two other directions, or vice versa. A handle placed on top of the valve turns the diverter 180 degrees in either direction, directing the flow and mixture of water that passes through the circulation system.

The suction line from the pool enters one arm of the valve body while suction from the hot tub enters the other. The diverter between the two arms determines which line is connected to the stem from which the water continues to the pump. Conversely, when the water leaves the equipment, it passes through another three-port valve. In this case, water passes through the stem and the diverter determines whether it flows to the arm plumbed into the pool return, or the arm into the hot tub return. By setting the diverter equally between the two, water from each side is mixed. When using the spill-over hot tub for sight and sound effects only, the hot tub’s return valve should be set to send the minimum amount of water needed to create the desired spill-over effect. Remember, the pool is designed to self-clean with water movement. If too much water is diverted to the spill-over hot tub, water circulation in the pool may suffer.

Extending the season

For this installation, two pumps were installed on the equipment pad. One is dedicated to the spill-over, with separate valves for each water feature component.

Customers want to maximize the time they spend in their outdoor oasis and a drop-in hot tub is the perfect way to allow them to enjoy their backyard into the winter. Even when the pool is closed, the hot tub can remain open. As the snow begins to melt in March, the hot tub can be opened before the pool thanks to the two separate plumbing systems, which offers homeowners flexibility when it comes to using the pool and/or hot tub.

For those clients looking to use their hot tub year-round (or close to it), it is preferable to have a drop-in hot tub without the spill-over feature. This is because there will be water displacement each time the hot tub is used, which results in having to constantly add water to the hot tub throughout the winter. Therefore, if the client plans on using the hot tub throughout the year, it is a good idea to suggest they do not select a spill-over model.

Maintaining three-port valves

Lubrication is the most important measure to take when it comes to maintaining a three-port valve. The gasket must be lubricated with pure silicone; most other lubricants are petroleum based, which can dissolve the gasket and create leaks.

Lubrication should be done when operation feels stiff, or at least every six months. This is especially important for motorized valves because the motor will strain against old, sticky gaskets until the diverter and shaft break, or the motor burns out.

Keep in mind, three-port valves, like any valves, can leak. Leaks can also occur inside the valve with no visible external evidence. Should this happen, the water is no longer being completely diverted in the intended direction, but rather slips past the diverter seal to the closed side of the valve. As a result, the hot tub will either drain or overflow for no apparent reason.

The cause might be a diverter that is not aligned precisely toward the intended port. In this case, the diverter should be removed to make sure the shaft has not separated or become loose.

With a motorized unit, ensure the motor is clean, free of rust, and able to perform a precise one-half turn each time. In most cases, however, the diverter gasket has likely worn out or become too compressed to stop all water from passing through. Bypass leaks also result when the diverter itself has shrunk or become warped. This happens, in some cases, when the hot tub water is extremely hot or the system ran dry and overheated. This type of shrinkage can be difficult to detect, as it does not have to be extensive to cause a bypass leak.

Valve placement

The drop-in hot tub can be placed anywhere in the backyard but, ideally, the pump should be kept as close as possible.

Typically, the equipment pad is located away from the pool and hot tub. However, some builders prefer to place the manual valves near the hot tub rather than in the equipment area for user convenience.

“We have always placed the equipment near the hot tub for ease of use,” says Perciballi. “Today, however, there are many automated options that allow users to have remote control access to the operation of the hot tub, water temperature, and jet functions. Most homeowners prefer this type of operation.”

When manual valves are used, there are several common mistakes that can occur as the homeowner becomes familiar with their pool/hot tub combination. The most common mistake is opening the hot tub suction, but forgetting to close the pool return. Another common mistake, which provides the same result, is closing the pool return, but not the pool cleaner.

“These user errors can be avoided by using the automation systems available today,” says Perciballi. “We didn’t have automation as an option for our customers 25 years ago, but we do now and our customers want automation, especially with a pool and hot tub combination.”

Everything today is becoming automated; therefore, pool builders need to embrace this technology when installing pools with drop-in hot tubs. Today, homeowners who have a hot tub attached to their pool are looking to maximize their hydrotherapy experience. By installing an automation system, the homeowner can, at the touch of a button, easily switch modes from pool to hot tub.

More and more pool owners are now using their mobile ‘smart’ devices—from anywhere—to check their hot tub water temperature and/or make adjustments to ready their pool and/or hot tub for when they get home from work. Pool builders who do not embrace automation for their pool and drop-in hot tub projects are leaving money on the table. Even if an automation system is not installed in the first year, be sure to revisit the client a year after they have been manually adjusting the hot tub water and sell them the convenience of automation, as they will likely be much more interested.

Winterizing a drop-in hot tub

In the winter, it is important to never completely drain a drop-in hot tub because underground water can easily lift the unit out of the ground. As previously mentioned, in Canada, most homeowners keep their hot tub open into late fall-early winter, but still close the hot tub during the extremely cold months. That said, the hot tub should be winterized and water should be removed from the lines, but it is recommended the hot tub be ‘weighted’ during the months it is closed. Some service professionals will line the hot tub with vinyl and then add water for weight. Keeping water in the hot tub (up to normal operation level) will equalize any water pressure under the shell and prevent it from lifting.

A growing trend

Building pools with drop-in hot tubs is a growing trend. Builders are increasingly getting more requests from customers interested in having the exercise advantages of a pool and the relaxation benefits of the hot tub side-by-side. Further, drop-in hot tubs provide great profit margins and builders—as well as homeowners—are embracing the trend when it comes to new pool installations and/or backyard renovation projects.

Hoffman_Headshot[7]Dave Hoffman is the national service manager for Fox Pools. He has more than 35 years of experience helping builders with pool and drop-in hot tub installation projects. He can be reached via e-mail at[8].

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