Hot Tub / Spa Winterizing

If you work in a cold climate, I probably don't need to tell you that a body of water needs to be prepared for the winter months. But even in warmer climates, you might discover that some of the following information is useful. Water expands when it freezes, meaning that if it is trapped inside pipes and equipment, it will expand and crack them. PVC pipes, fittings, and ABS plastic pump parts are most susceptible, but soft copper heat exchangers and galvanized fill-line pipes are not exempt either. Expanding frozen water will also crack tiles and plastic skimmers.

The second problem, which relates to a winter seasonal closure of a hot tub, is potential damage from algae and debris. Although algae do not grow well in temperatures below 55°F (13°C), especially if the water is shielded from sunlight by a cover, prolonged periods of stagnation will permit and promote algae development.

Above-ground plastic hot tubs can be drained completely, although inground gunite and large plastic hot tubs should be treated just as pools are—the plumbing and equipment must be prepared for winter as described below.

Winterizing the hot tub

RATING: MODERATE

1. Balance the Chemistry Etching or scaling conditions of water will harm the hot tub even when the circulation is off; so before closing it, make sure the chemistry of the water is balanced.

2. Cleaning Dirt and debris left in the water during long periods of stagnation will leave stains and/or be much harder to remove several months later. Therefore, thoroughly service and clean the hot tub before closure.

3. Algae and Stain Prevention To prevent algae growth and staining during the closure, superchlorinate the water. A simple formula is to triple the superchlorination that you usually use for the particular installation. A more precise approach is to raise the residual to 30 ppm for plaster surfaces and 10 ppm for vinyl or plastic. Add a metal chelating agent to prevent metals from dropping out of solution and staining the surfaces. Finally, add an algaecide that will inhibit black algae growth (I prefer silver-based products).

Do not leave tablets or floaters in a hot tub during closure. Since the water isn't circulating, the chemical isn't dissolving either. The extreme concentrations in one area can do structural or cosmetic damage, particularly to vinyl or plastic surfaces.

4. Shut Down the Equipment Turn off the circulation equipment at the breakers, and tape them over to prevent someone's turning them back on. Turn off all manual switches and time clocks, and remove the trippers as an added precaution in case someone does turn the breakers back on. Pay special attention to lights, which may be on household circuits rather than wired through the equipment breakers. Some technicians don't disconnect underwater lights if the water level will remain above the fixture all winter. The light provides a little warmth to the water periodically and draws the owner's attention to the hot tub for regular inspection. I have seen light lenses crack, however, as the extremely cold water and extremely hot light fixtures repeatedly contact, so I don't recommend this practice.

5. Lower the Water Level Pump out 24 to 36 inches (61 to 91 centimeters) of water, or at least enough to drop the level 18 inches (45 centimeters) below the tile and skimmer line. When water freezes and expands, it can crack the tile and plastic skimmer components, so the goal is to lower the level to a point where winter rain or snow will not raise it back up to those delicate areas. The hot tub should not be drained completely for the season, since hydrostatic pressures may cause cracks of the entire vessel to pop out of the ground.

6. Clear the Lines Perhaps the most important objective of winterizing is to protect the plumbing from freeze damage. There are several methods, some easier than others. The method you choose may depend on your equipment, skills, and the availability of water in your area.

The most effective method of protection is to entirely drain the hot tub, making complete evacuation of the lines possible. Of course you would then refill it to the level discussed in step 5. If the water needs draining anyway for chemistry reasons, this is an opportunity to accomplish two tasks at once. The cost or availability of water in your area may prohibit annual draining; but if you can, it is the most effective way to be sure all water has been removed from the system. Even small amounts of frozen water can crack pipes and fittings.

With the hot tub empty, remove the collar/nozzle fittings from return lines and plug them with rubber expandable test plugs. The main drain may still have water in the bottom of the plumbing, so try to suck it out with a wet/dry shop vacuum, or mop it out with a sponge. Just to be sure, pour a cup of antifreeze into the main drain before plugging it. For antifreeze, use a mixture of 1 part propylene glycol to 2 parts water. Your supply house will have propylene glycol or premixed products. Never use automotive antifreeze, which is corrosive. With all the lines plugged, refill the hot tub to the level described above.

The return lines can also be filled with antifreeze by starting the pump with the strainer pot lid open. With the pump running, pour the mixture into the pump. It will be distributed throughout the equipment, plumbing, and return lines. When you can see antifreeze discharging from all the return lines, you can turn off the system and plug the return outlets. You may want to add some food dye to the mix to make it easier to see the concentration discharging to the hot tub.

7. Remove Equipment Any equipment in the hot tub or circulation system that may be damaged by exposure to the elements (or which may be stolen) should be removed and stored. The circulation equipment should be disassembled and important components stored. If the pump/motor is plumbed with unions, you can easily remove the entire unit and disconnect the electrical connection. If there are no unions, you might want to cut the plumbing and add the unions when you reinstall, to make the process easier next season. If the plumbing makes removal of the pump difficult, unbolt the wet end and motor from the volute and remove those.

Disassemble the filter, clean and thoroughly drain the tank, and put the grids or cartridges in storage. Freezing water can cause fabric deterioration. Sand filters should be cleaned and drained. Since rain might refill an open filter tank, close the tank and leave the drain plug out.

Shut the gas valve to the heater and any supply valve (if it is a dedicated line for the hot tub heater) at the meter. The heater has drain plugs on both sides. I recommend removing the heat exchanger and burner tray and storing them after draining. Drain the water from the pressure switch tube as well.

Drain down any solar panels, and leave the plumbing fittings or gate valves open to the atmosphere. Even in winter the heat in a solar panel can be intense, and expanding air can be as hazardous to the panels as freezing water.

Be sure the lines between the equipment are empty or at least filled with antifreeze. Remove any hot tub jet booster pumps and store them. Leave all valves open and disassemble any three-port valves. Finally, if the hot tub has a fill line, shut off the water supply and drain that line as well.

8. Extra Precautions Put a little dirt or gravel in an empty plastic bottle and leave it in the skimmer. The weight will help it stay upright in the skimmer if rain or snow refills it with water. Should the water subsequently freeze, the ice will compress the bottle, not crack the skimmer. Similarly, leave some plastic milk or chlorine jug floating on the surface of the hot tub. Fill them about one-fourth witY water so they will "grip" if the water freezes and not just pop ou onto the surface of the ice. Again, the goal is to create an expansion joint so that the ice will crush the jugs, not the hot tub walls.

If there are exposed pipes, which you suspect may still contain water, in the equipment area, under decks, or in self-contained hot tub cabinets, wrap them with insulation tape (a good idea anyway, to reduce heat loss when operating the system). In extremely cold areas, wrap them with electrical insulation tape, available at most hardware stores on a seasonal basis. These tapes actually warm the pipe with a low-level electric current, plugging into wall outlets.

The air blower ring must be drained also. When the hot tub is empty, use the blower to evacuate the line. If you need to refill the hot tub, pour antifreeze over the air holes so it penetrates the openings. Then dry the surface and apply duct tape over the holes before refilling the hot tub. When you reopen the hot tub, you will probably need to clean the tape adhesive off with acetone, but the extra effort is better than finding a leaking hot tub.

If metal rails and light fixtures cannot be removed, protect them against corrosion with a coat of petroleum jelly.

9. Cover the hot tub Some cover is better than none, as it will inhibit algae growth and keep heavy debris out of the hot tub. Sheet vinyl covers are very inexpensive and can be held in place with rocks or sandbags around the edge of the hot tub. Put your expensive foam or custom cover in storage to protect it over the winter too.

10. Shut Off Access to the hot tub Whether it is a commercial or residential hot tub, blocking access to the closed installation is an important safety precaution. Yellow caution tape strung around the hot tub, locked gates and fences, and extra signage will keep the hot tub from becoming an inadvertent hazard and will limit your liability.

11. Clean Up Take this opportunity to properly dispose of any extra chemicals or test kit reagents that won't be used during the winter and will not be potent in the spring. Soda ash and acids are about the only water chemicals that will still be good after prolonged storage, so make sure they are packed in watertight containers and stored in well-ventilated areas away from water or heat sources.

During the winter you will still need to check on the hot tub. Snow r rain may have raised the water level or sunk the cover. Animals or Hleavy debris may have fallen in the hot tub and would be better removed Jow than in spring.

Reopening the hot tub is essentially the reverse of the shutdown procedure, with emphasis on balancing the water before restarting the circuation system.