Pool Skimmer Winter Protection

How to Identify, Correct and Prevent clogged impellers
by Mark Garcia September 12, 2014

How to Winterize a Pool Skimmer

How to Winterize a Pool SkimmerWhether your pool is inground or aboveground, if it sits in the snowbelt, you'll want to winterize it correctly to prevent ice damage to the skimmer walls and the pipes attached underneath.

Today's post covers winterizing pool skimmers - what to do during closing the pool to ensure your skimmer will be functional for many years to come. Because, no one wants to replace a pool skimmer - it's a very difficult job.

There are two parts to winterizing a pool skimmer, the first part being draining or blowing (or sucking) the water out of the skimmer and the pipe that leads to the pump, and the second part being protecting the skimmer from the ice that will form inside of the skimmer (on top of the plug), from rain and snow melt, or from water splashing into the skimmer from the pool.

Above Ground Pool Skimmer Winterization

For most above ground pools, the skimmer is exposed, and it's easy to remove the hose that connects to the filter system. If that's the case for your pool, disconnect the clamp band and carefully (gently) remove the hose from the bottom of the skimmer. Store the hoses indoors for the winter, along with the entire pump and filter system, if you can manage that.

Hoses: After disconnecting the hoses, the water will drain down below the skimmer, and pour out on the ground. And since the skimmer is not connected to any pipes, there is no need to plug the skimmer, any rain or pool water that gets in will simply drain out. However, it may not be wise to have the skimmer constantly drain water up against the edge of the pool. Over time, the ground will soften and your pool may start to list to one side. Better to leave the hose connected, so that the skimmer drains several feet away from the pool. Be sure to use rigid hose (not backwash hose, which can fill with ice all the way up to the skimmer), so that the water will run out unimpeded.

Pipes: If your pool equipment is hard plumbed, with rigid PVC pipe instead of removable hoses, you'll need to use other methods. The best method is to use air to blow out the line. Get a large wet/dry vac, rent or borrow if you don't have one, and reverse the hose so that it blows air out, instead of sucking air in. Remove the pump lid and pump drain plugs, and stick the wet/dry vac hose down into the skimmer,. Hold it firmly over the hole while you turn on the vac, to blow water from the skimmer to the pump. When empty, plug the hole in the bottom of the skimmer with an expansion plug, Skimmer Guard or Threaded Plug with o-ring.

You'll need the water to be below the skimmer to blow out the skimmer pipe, unless you install an Aquador, Lid'l Seal or Skimmer Plug. All of these allow seal up the opening to the skimmer, to keep the pool water from entering the skimmer. The first two come with a new skimmer faceplate that you install, and a Tupperwaretype of lid snaps onto the front. The Skimmer Plug is a new concept. Made of soft but rigid rubber, it pushes into your existing skimmer faceplate, making a tight seal around the inside of the faceplate opening.

Even though you may keep the pool water out of the skimmer - you still have rain and snow that will get in thru the skimmer lid, which will turn to ice. Water expands 10% when frozen, and can shatter a skimmer like it was made of paper. To protect your skimmer from this, place a 12" square piece of heavy plastic between the skimmer lid and skimmer body, and tighten up the screws, or place a heavy stone on top. Alternatively, you can use the Skimmer Guard, or drop in a (clean) bottle that is one third full of pea gravel or pool antifreeze. This will absorb the expansion of ice. Place a heavy object on top of the skimmer lid to hold the bottle in place as the water rises, and also to prevent the wind from tossing your skimmer lid around the yard like a Frisbee™. 

 Whether your pool is inground or aboveground, if it sits in the snowbelt, you'll want to winterize it correctly to prevent ice damage to the skimmer walls and the pipes attached underneath.

Today's post covers winterizing pool skimmers - what to do during closing the pool to ensure your skimmer will be functional for many years to come. Because, no one wants to replace a pool skimmer - it's a very difficult job.

There are two parts to winterizing a pool skimmer, the first part being draining or blowing (or sucking) the water out of the skimmer and the pipe that leads to the pump, and the second part being protecting the skimmer from the ice that will form inside of the skimmer (on top of the plug), from rain and snow melt, or from water splashing into the skimmer from the pool.

In Ground Pool Skimmer Winterization

For inground pools, skimmer winterization depends on which type of skimmer plumbing configuration you have. Many inground pool skimmers have two holes in the bottom. This is to give the pool builder some flexibility in plumbing, allowing them to tie in an equalizer line, or a main drain into the front hole, and connect the back hole to the pipe that runs to the pump. In many cases, the front hole is plugged on the bottom and not used, and the back hole is connected to the pipe that runs to the pump.

And there are inground pool skimmers that have only one hole, in the center bottom. These may also be connected to a main drain, or they may be connected to a single pipe, which runs back to the pump. Let's explore several different plumbing configurations and discuss how to winterize each type. 

 

Dedicated Skimmer: This type of skimmer is a dedicated skimmer line, no other line is connected into the skimmer. If your pool has more than one skimmer, they may join each other underground, or if you have a separate valve for each, in front of the pump, then they do not. This is the most common type of arrangement, on pools built in the last 20 years.

This type of arrangement is best blown out with air, from the skimmer to the pump. Open up the pump lid and remove the drain plugs to make it easier to blow out. You can use a 5hp Shop Vac™, a Cyclone blower, or a small air compressor to do the job. Nothing is done with the front hole, since there is no pipe connected. On some pools, a builder may have plumbed to the front hole, and plugged the back hole.

 

Combo Skimmer: Side by Side: A "combo skimmer" is one which has the main drain plumbed into the skimmer, to reduce cost by not running a separate pipe for the main drain all the way back to the pump, with a separate valve to control the main drain flow. In this arrangement, the front hole has been plumbed with a pipe from the main drain, and the back hole is connected to the pipe that runs back to the pump. A spaceship looking diverter (I call it a Turtle), sits in the bottom, and allows for some control of the flow from top-down (skimmer) and bottom-up (drain). 

To winterize this type of skimmer, first lower the water in the pool to your winter level (4" below skimmer for solid covers, 12" below for mesh covers). The skimmer should be mostly empty of water. Pour antifreeze into the main drain hole, about 1/2 gallon, and you'll notice that the heavy pool antifreeze will cause the water in the main drain pipe to drop, or go lower in the pipe. As it drops, quickly plug the main drain hole with a properly fitting plug, twisting it tightly in place.

For the back hole, the pipe that runs to the skimmer, blow out the line with a wet/dry vac, Cyclone blower or air compressor. Alternatively, you can use pool antifreeze in the pipe, adding one gallon for every 10 feet of pipe.  

 

Combo Skimmer: Old Style Sylvan: In this type of combination skimmer, used by Sylvan pools in the 70's and 80's, the main drain line is tied into the pipe underneath the skimmer, and is not visible from above. To vacuum this type of pool, one uses a 'skimmer stick', a piece of 1-1/4" black pipe that drops down into the skimmer, and effectively blocks off the suction from the drain. This type of skimmer can be identified by the presence of single main drains in the deep end, and also in the shallow end. The return lines are also located directly below the skimmer, on the wall.

To winterize an Old Style Sylvan skimmer, one would use a long double plug, which has two plugs mounted on a long brass rod. Typically the plugs used are a #7 on the bottom and a #9 on the top. This is a very specialized plug, we used to sell it, but I no longer see it on our website... I see that other online retailers carry it however.

Using this plug is also specialized. The way we would do it is to push it into the skimmer hole, about 3/4 of the way down, and then blow air from the pump towards the skimmer. Be careful to hold the plug while blowing air, it could blow straight up and injure someone. While blowing, air (and water spray) will be blowing up out of the skimmer, and eventually air will bubble out of the drain. After bubbling air out of the drain for about 30 seconds, quickly slam the plug down to its full depth and tighten up the wingnut, while the blower is still blowing.

Alternatively, you can fill the pipes up with pool antifreeze and then install the plug. On very old Sylvan skimmers, especially Aluminum skimmers (any of those still out there?), the seal is not good, even with the correct plug, so pool antifreeze is called for. Anytime you are unable to blow out a line completely, you can pour in pool antifreeze (propylene glycol), at a measured amount of 1 gallon for every 10 feet of pipe.

 

Combo Skimmer: Old Style Anthony: In this type of combination skimmer, used by Anthony pools in the 70's and 80's, the main drain line is tied into the pipe beneath the skimmer, not visible from above. Similar to the Sylvan set-up, but different, as the drain comes in from the bottom and not the side. Like the Old Style Sylvan, the skimmer will have a single hole, but Anthony used a threaded diverter that inserts into the hole and could be turned from Full Skim to Full Drain. Many of these pools have only one pipe coming into the pump, unless there was more than one skimmer, or an attached spa.

To winterize an Old Style Anthony skimmer, one could use also use a double plug, one that is shorter, made with a #8 plug on the bottom, and a #9 plug on the top. Or, what we would do is use an extended #8 plug, and reach down into the skimmer, holding the plug with long straight pliers. Push the plug down until it comes to rest on the lip of the fitting which is the start of the main drain pipe and then tighten it up. This plugs off the main drain line, and is just below the opening (on the side) to the skimmer pipe.

Be sure to use an extended plug, so you can reach it with pliers, and it must be #8, a smaller plug could slip into the main drain line, which creates a real headache trying to get it back out, and a larger plug won't go down far enough.

After plugging the main drain (you can pour in some pool antifreeze first if you wish), then you are free to blow out the skimmer line, using a large wet/dry vac, Cyclone blower or air compressor. Blow air from the skimmer towards the pump, with the pump lid and drain plugs removed. When all of the air is out of the line, splash in another cup of pool antifreeze, and then plug the skimmer with a #9 or #10 expansion plug.

 

Skimmer Bottles: After you have blown out the lines, or filled them with antifreeze and plugged the skimmer there is still one more step. Over the winter, the skimmer will fill up with water, splashing in from the pool, or from rain and snow melt leaking in around the skimmer lid. This water will freeze, and may crack the skimmer sidewalls. There are a few ways to deal with this. Vinyl pools can use an Aquador or Lid'L Seal, as described for aboveground pools, and the lid can be sealed with a heavy piece of plastic sandwiched between the skimmer body and skimmer lid to keep out rain. 

You can also just pour pool antifreeze into the skimmer, but that makes a slimy mess come springtime, and the antifreeze tends to make the plugs all slimy and maybe shorten their lifespan. What we like to do is pour pool antifreeze into an empty winter algaecide bottle, about one-third full, cap it, and drop it in the skimmer. The weight of the antifreeze holds the bottle down into the water as it builds up, and when it freezes, it will collapse the sides of the bottle instead of the sides of your skimmer.

Caution: Be sure to rinse out the algaecide bottle very well before adding antifreeze, these two chemicals can react violently. Alternatively, you can fill the bottle with enough pea gravel or sand to keep it floating halfway submerged in water. Or, you can wedge in a gallon bottle or milk jug to take up most of the space, and weigh down the skimmer lid, so it won't float up out of the skimmer. You could also screw down the skimmer lid, using the proper sized tiny screws.

 

Thanks for Reading! 
Mark Garcia