Blowing out the water lines is one of the most important steps of winterizing your RV. So if you plan to dock your RV for the winter or have it sit in a potentially cold area for a while, you will need to know how to blow out RV water lines.
But how do you blow out the water lines on your RV? What tools, equipment and expertise do you need to properly winterize your RV?
The best way to blow out your RV water lines is to use a compressor and blowout plugs. The compressor forces air into your RV water lines and removes water.
How do I get started blowing out the water lines in my RV?
There are a few safety precautions to take before you start blowing out the water lines for your RV. A little planning is helpful here.
- Start by turning off your water heater about one day in advance. This will prevent hot water from entering the lines.
- Make sure the drain tanks are open
- Drain your gray and blackwater tanks. You wonโt necessarily need to drain your freshwater tank using this method. Disconnect your water supply and turn the drain pump off so water doesnโt continue to move.
- After your water heater is cooled, drain the water heater by opening the pressure valve (or your water heater manuals specified method)
- Turn on all faucets to allow both excess hot and cold water to drain
This will ensure that all the water within your RV is out and leaves only excess water that could be sitting somewhere in lines.
Using an air compressor to blow out the RV water lines
A couple more steps here before we really blow the air line of your water lines.
- Locate the RV water inlet on the exterior of your RV. This will be close to your tanks is generally in a panel on one side of your vehicle. It probably wonโt be on back.
- Install a blowout plug in the RV water inlet. This usually screws in by rotating it right.
- Set the air compressor to 30 to 40 pounds per square inch, you shouldnโt need more than this pressure.
- Screw the air compressor hose into the blowout plug, generally be turning right on the nut on the neck of the hose.
- Turn the compressor on and let it blow in for about 2 minutes.
- Turn the compressor off.
Blow Out RV Water Lines
- Open the water valves to drain them one by one โ assuming you have multiple water valves for the purpose โ youโll generally have at least one hot and one cold.
- You can also add more air pressure to individual lines by inserting the air compressor hose into the valve
Youโll now want to let your tanks drain again to release any excess water that was removed by the air pressure. You wonโt really know if there is more air trapped in the lines, so the best sign that your air pressure worked is that a little water comes out.
You can now remove the blowout plug from the water inlet and replace it with a regular water intake.
Safety precautions when you Blow Out RV Water Lines
Here are a few safety tips
- Donโt get your air compressor to higher than 30 to 40 PSI. Using higher pressure can damage the lines. 30 to 40 is enough to push water around.
- You might want a 10 gallon compressor to start, at least. While 2 gallon compressors are available, that might not be enough air to completely pressureize a larger RVโs water lines. Rather than doing the process repeatedly or slowly, a larger compressor is more efficient and will draw more water out, making your winterization more effective.
- Store the blowout plug in a safe place. Itโs not dangerous, itโs just a rather small tool that you might need in a pinch when winterizing and itโs good to keep it someplace youโll remember.
- Put the air compressor away right away. Kids can accidentally use it and cause potential problems โ air comes out really fast.
Why Do I Need Know How to Blow Out RV Water Lines?
Water can get trapped in various places in your RVโs water lines. When the temperature starts to drop, that water can readily freeze into ice. Ice expands and fills the water line tubes and can cause blockages โ or worse yet, breaks and flooding.
Blowing out RV water lines is especially important if you plan to have your RV sit for a while, unused. If you plan to use your RV in the cold, itโs also a good idea to add RV specific antifreeze to the water in the amount suggested on the bottle.
RV antifreeze has a lower freezing temperature than water and will keep water from freezing. This is also a good idea generally if you plan to keep water stored in the RV just in case you do go somewhere.
Overall, whether you are planning to go somewhere or not, blowing out your water lines while not immediately using your RV is a good precaution to take in that event the weather suddenly gets colder. It’s part of winterizing an RV.
This process is much like wrapping your homeโs exterior water spigot with insulation or cutting off the water supply to the spigot. Itโs a bit more important in an RV because there is a better chance of water freezing.
How Much Air Pressure is Needed to Blow Out RV Water Lines?
New to maintaining RVs? Chances are youโve never blown out water lines when winterizing your home or even your car. RVs are a bit different in their need for winterization. They run a higher risk of freezing with water inside, which is never a good thing.
So we are on the question of how you blow out your RV water lines. How much air pressure is necessary? How much is too much?
Youโll want from 30 pounds per square inch all the way up to 50 pounds per square inch. The range is fairly small, but necessary to keep your plumbing intact while completing the task effectively.
Why 30 pounds per square inch to 50 pounds per square inch?
RV water lines are a bit different from your home water lines. Most of the times, your home water lines use copper (or if they are really old, lead) which is quite durable. RVโs tend to use PEX plastic tubing, which is effective for a smaller place, and cheaper to construct.
PEX plastic tubing is less durable, though generally works quite well for RVs. While a copper pipe might be able to take a higher amount of pressure, a PEX plastic tube can allow about 50 PSI of air to run through it without the potential for causing more damage than helping.
30-50 is also enough to move water
The PSI amount suggested for blowing out water lines is also enough to push remaining water around and loosen things up when winterizing.
What risks do I have when using too much pressure?
PEX tubes use seals that allow the tubes to connect across multiple rooms in your RV. Using too much pressure can cause premature wear on the seals and result in leaks further down the road. While cleaning up a leak is fairly easy, the water has the potential to damage furniture, electronics, and other things that get caught up in itโs path.
How do I use the compressor for 30-50 PSI?
One common misconception about compressors is that you need a big compressor for a big RV. Whatโs more necessary for an RV water line is a moderate amount of pressure for a few minutes. A lower capacity air compressor of 2 gallons isnโt a bad thing โ the larger downside to a smaller air compressor is that it will take longer to fill the entire RV with air, because they are generally lower powered too. In the context of not damaging the RV, this shouldnโt be a problem.
The most effective water line blowing routine involves setting the compressor for less than 50 PSI and letting it sit for at least a few minutes while the water lines fill with air.
Using a smaller compressor that isnโt capable of significantly more than 50 PSI also helps. You might want to consult with your manual in regards to exactly how to set your PSI to a limit before starting it and plugging in to your water lines.
Check your RV manual
Weโve suggested a range of pounds per square inches to blow the water of your RV lines. We also strongly suggest consulting the manual for your RV to make sure that you are using the right amount for you.
Why? Besides having a small amount of water draining after you blow them out, itโs difficult to tell if the process actually worked. If you used too little air pressure, you risk not actually moving any air and moving on without a fully winterized vehicle.
If you use too much, you risk blowing some seals and having a nasty water surprise when you were trying to relax.
The manual will tell you exactly how much air is necessary based on your actual plumbing setup.
Keep an eye on the air compressor
Air compressors can do some weird things, including losing the ability to regulate the air pressure. Itโs ok to have unusually high air pressure while using a drill, but not so much when blowing out water pipes for an RV. Youโll want to be attentive to a compressor, especially an older or cheaper one, to make sure you are getting a consistent flow of air that doesnโt cause damage.
Do I use different amounts depending on the line?
Youโll want to use the same amount of pressure per line unless specified in the manual. The manual is not likely to request a different amount of pressure per hot or cold line.
Should I do anything else besides blowing out the air lines?
Yes, we recommend adding RV antifreeze to your water lines. Itโs safe to drink when diluted by a tank of water and can be added again.
As we mentioned earlier, itโs important to know that there is almost no way to know if you have additional water in your lines. Antifreeze gives you a much better chance at keeping your pipes from freezing at minimal expense. Doing both a blowout and antifreeze will help you rest assured you wonโt have future plumbing issues.
Do I open the line and put the compressor hose in?
No, you should get a blowout plug for your RV water lines. These plugs allow you to connect the air hose to the line with a screw-in plug. This keeps the hose stable and prevents you from actually putting the hose directly into the inlet. These are cheap at hardware store and should be stored properly โ they are small and easily lost.
Final Thoughts on How to Blow Out RV Water Lines
Blowing out your air lines is one essential step in winterizing your RV. This is especially true if you plan to have the RV sit for a while. Itโs also a great precaution in case a cold snap catches you.
With a little bit of knowledge and precaution, making your RV safe for colder temperatures is easy. Our basic suggestions are to use a smaller compressor that has a lower PSI range, and of course to read the manuals for both the compressor and the RV. Your RV might ask for something unexpected, and the process of winterizing will be easier if you know what it asks for.
A few simple rules are to use a large enough compressor โ like 10 gallons or more, for your RV, and keep that blowout plug safe. You might need it suddenly!
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