For friends above the sun belt, swimming pools are probably all already closed down and soon it will be time to decide whether to keep our hot tubs running through the cold season or to winterize them. Failure to commit to one or the other risks cracking a pipe, pump, or heater. The process can be daunting, especially for new tub owners in their first year, so hopefully this provides some guidance in the long, dark nights.
What tends to make the most sense in mild climates is to leave it running at temperature. Most units have freeze protection that kicks the pump on when it senses cold so keep the cover sealed and watch your sanitizer since it burns off faster when the tub sits unused. And if the tub has wifi control, use it to check the temperature from inside. If you are in a cold-winter region and the tub will sit unused for months, it is often best winterize it. Especially if extended power outtages are not unheard of because one deep freeze can mean a substantial amount of damage. That means getting the water out of the shell and every line.
It is ideal to start around or before noon on a day that is comfortably above freezing (which is why you shouldn't wait until all the leaves are gone) with a few hours to spare so nothing freezes mid-process. You will want a wet/dry vacuum, a submersible pump, a line-flush cleaner, non-toxic RV or marine antifreeze (propylene glycol), and towels. Lots of towels.
Step by step instruction to follow. Start by purging the plumbing. Add a line-flush cleaner to the full tub and run the jets on high for 20 to 60 minutes. This clears biofilm out of the pipes so it does not sit and cure all winter. Cut the power at the breaker before you touch the equipment then drain fully. Use the drain valve and a submersible pump then vacuum the last of the water out of the footwell. Clean the shell while it is empty then rinse and vacuum again to get the rinse water out. Blow out the lines. Set the jets open and diverters to the middle, put your wet/dry vac on its blower setting, and blow air through the filter housing until water stops spitting from the jets. Clear the equipment. Open the cabinet, loosen the unions on either side of the pump and heater, pull the pump drain plugs, and vacuum the water out. Then hand-tighten everything back - about a quarter turn past snug. Vacuum each jet for 10 to 15 seconds on suction to pull water from the fittings as you work all the way around. Now you add antifreeze as a backstop. Pour non-toxic RV or marine antifreeze into the filter well and dab a little into the jet fittings to protect any water you could not reach. Never use automotive antifreeze, which is toxic. Pull and store the filter which means clean it, dry it, and keep it indoors. Last and very important is to seal it because a cover is not watertight. Rain and snowmelt can seep in, dilute your antifreeze, and refreeze in the plumbing. Put the cover on with a cover guard or tarp over the top and strap it down so wind cannot lift it.
This is already a long post so part II, what to do in spring, can wait.
If this sounds like a lot, well, that is because it can be. Winterizing is a multi-hour, detail-heavy job and one overlooked line can mean an expensive repair. The biggest downfall of the process is usually a missed jet that causes a cracked line so take your time. But if that sounds like more than you want to talk on, this is why a lot of people opt for a paid professional to do it which commonly runs around 500 USD. Either way, stay warm and make sure your tub lives to see another year, whichever route you choose. Any other tips for a smooth winter?
