How to Blow Out Pool Lines for Winter

blow out the lines for winterBack when I had a pool service company, we had a few customers we saw only once per year. These were very hands-on, DIY clients, who would have their pool completely closed, and called us out for our blow-only service, to winterize the underground lines.

Blowing out the lines is not so complicated, anyone can do it, with the right equipment.

The right equipment for the job, in this instance, is the Cyclone pool blower, shown right. A suitable substitute to purge pool lines would be the Mighty Vac Blower Vac.

Can you blow out the lines using an air compressor? Yes, you could use a suitable compressor to blow out pool lines, but the potential exists to over-pressurize your pipes and fittings with a compressor. Compressors are high air pressure, low air flow. Cyclone pool line blowers, on the other hand, have low and consistent pressure, with a great deal more air volume being produced.

Can you blow out the pool lines using a Shop Vac? Maybe. Large, canister types of 5hp or more should be able to handle the resistance of the water. Some wet/dry vacs will release excess air pressure under heavy resistance, but may still be able to blow out skimmers and return lines. The biggest problem is that most wet/dry vacs won’t blow out a main drain line, same with some compressors.

Can you blow out the pool lines using a Leaf Blower? It seems logical, that it could work, but – I’ve tried it in a pinch with fairly powerful, gas powered leaf blowers. We had fun – used a lot of duct tape, but had very little success. It may work for shallow skimmer and return lines, after lowering the water level.

Can you blow out the pool lines using a Bicycle Pump? This seems not so logical, but according to this pool forum post, an inventive couple used their Bicycle pump and pumped air into the main drain line. Not sure if they actually “blew out” all of the water in the line, however. You need a high volume of air pushing through to prevent the water from coming back into the pipe, while you either plug the line (returns), or close off the valve (main drains).

Cyclone Pool Line Blower

The Cyclone pool line blower will blow main drains without even lowering the pool water level, and have no problem with deep lines, small lines or large lines. Cyclone air blowers are also portable, durable and easy to use. And, did you know – Cyclone air blowers are also used as a vacuum to set pool liners? Come to think of it, you could use the Cyclone to blow out lawn sprinkler systems, too!

So, let’s assume that we are using the Cyclone pool line blower to blow out our pool plumbing lines, shall we?

Preparation to blow out the lines:

  • Lower the water level 4-12″ below skimmer, depending on cover type
  • Drain, hand pump or scoop water out of skimmers until almost empty
  • Set multiport valve to Recirculate, Filter position for slide valves

Connect your Cyclone to your Skimmer:

You’ll need to have two extra items, I’ve neglected to mention until now. A small 3 or 6 ft. section of hose to connect to the Cyclone, and a hose adapter to screw into the bottom of the skimmer.

Most inground pool skimmers have two holes in the bottom when you look down into them, and usually the pool side hole is blocked off, and the deck side hole is connected to the pipe.

If both holes in the skimmer are open, then you have what I call a “Combo Skimmer”, the pool side hole in the bottom connecting to the bottom drain of the pool, and the deck side connected to the skimmer pipe. For combo skimmers, plug the main drain hole with a winter pool plug, and thread your hose adapter into the other hole that leads to the pump.

Thread the 1.5″ hose adapter into the bottom hole in your skimmer that connects to the pump. If your skimmer has 2″ holes in the bottom, you can use a plumbing adapter available at any home store, called a 2″ x 1.5″ threaded reducer. This PVC fitting is threaded on both sides, inside and out, and will allow a standard hose adapter to fit a 2″ skimmer hole.

Attach the hose to the hose adapter, the other end to the Cyclone blower, and plug in your blower to an extension cord or directly into an outlet. You’re now ready to blow out your pool plumbing lines!

Blowing the pool lines is a 3-Step Process:

  1. Blow out the suction side
  2. Blow out the equipment
  3. Blow out the pressure side

1. Blow Out the Suction Side:

The suction side is all of the incoming lines. Most pools have 1 or 2 skimmers and a main drain line on the suction side of the pump. These are the pipes that join together and come into the pump.

If you have a second skimmer, you can blow air from one skimmer, to the pump and then back to the other skimmer. You will need to close a valve off at the pump, or pull off the pump lid and plug the port coming into the pump – in order to send the air through the other skimmer line.

If you have another hose, or a vacuum hose that you can connect to the other skimmer, this prevents reaching into the skimmer and plugging it while it’s spraying like a fountain. Blow air through the skimmer lines until just a mist is blowing out, or for about 2-3 minutes.

Now for the main drain. Re-position your valves to blow air back through the main drain. When you see the massive plume of air rise up, allow another 20 seconds and then close off a positively sealing valve (like a Jandy valve) on the main drain line, to hold the water back with a column of air.

If there are other suction lines like a cleaner line or a spa drain, turn the valves again to send the air from the skimmer to each of these lines separately.

2. Blow out the Equipment:

Now we will blow air through the pump and through the filter valve. Remove the drain plugs on the pump and allow the air to push all the water out. Replace the plugs loosely. If you have a heater, do the same with both drain plugs.

Filters are not normally blown through, the multiport valve should be set to “Recirculate”. If you have a slide valve, the air will have to go through the filter however. The Cyclone will have no problem with this pressure drop. Remove your filter drain plug if you haven’t already done so.

3. Blow out the Pressure Side:

Now that the air, coming from the skimmer, has blown through the pump, filter and heater – we can now send it back to the pool through the return lines.

The return lines closest to the pump will begin to blow first. After 2-3 minutes, plug the one that is bubbling the most, then plug the other return lines. Make a tight, positive seal with your pool plugs, no air bubbles should appear.

If you have other pressure side lines, like an automatic cleaner line or a spa return line, blow each of these out separately. If there is a spa blower on an attached spa, turn on the spa blower while you are blowing and plugging the spa jets.

Water Feature Pumps:

Waterfall and fountain pumps are usually blown out at the pump itself. The builder may have installed a tee fitting to connect a blower. If not, you may have to remove the pump lid and hold your blower hose.

To do this, push the hose into the pipe that comes into the pump, to blow air back (provided there is no one-way check valve installed) towards the pool. Secondly, remove the pump basket and place the air hose into the volute or impeller housing. Make a good seal and turn on the blower. This will blow out the pressure side of your water feature. Be sure to plug up any holes that may fill from rain water or rising pool water levels.

In-Floor Cleaner Systems:

If you have those pop-up jets on the steps and floor of your pool, locate the head unit, and remove the clamp band to expose the pipes that lead to the pop-up floor jets. Blow each pipe individually, and plug fast with an appropriate sized winter pool plug.

And that’s how we blow out the pipes for an inground swimming pool winterization!

Get a Cyclone pool pipe blower and stop paying hundreds of dollars for something you can do yourself. Once you start bragging about this to your neighbors, you (and your blower) may become very popular this time of year!

Davy Merino
InTheSwim Staff Editor


How to Blow Out Pool Lines for Winter — 4 Comments

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  3. You make mention of the combo skimmer above, but I am unclear how to blow out the main drain line. My combo skimmer, old Anthony pool, shows two threaded holes in the bottom. One leads back to the pump (suction) and one goes to the main drain. I can blow back from the skimmer to clear the suction line, but I am unclear as to how to clear the main drain from the skimmer since it will back fill when I remove the pressure. What is the manufacturers process to create an air lock on the main drain from a combo skimmer?

    • Hi generally, these lines are not blown out. In practice, you would simply plug the main drain hole, after lowering the water level. That”s how weve done it for years, without a problem (that I know of). If you really wanted to blow it out, you could use a test plug, the type with an air valve on top. Tighten up the rubber plug in the hole, and attach an air compressor hose to the air valve and in this manner, you can blow out the line, but it”s probably not necessary to do so.

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