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How to Winterize an RV with an Air Compressor

How to Winterize an RV with an Air Compressor

Winterizing your RV’s plumbing is incredibly important, especially if your RV will spend any time at all stored in sub-freezing temperatures over the winter months. Frozen water lines can quickly lead to burst water pipes, a broken water pump, and a devastating amount of damage to the RV itself. Proper RV winterizing of your plumbing system is something almost all RVers need to know how to do at one point or another. In today’s post, we’re talking about how to winterize an RV with an air compressor.

In yesterday’s post, we shared some helpful ideas to make your winter RV camping trip more tolerable enjoyable. Today we’re sharing a tip for RVers who will be storing, instead of wintering in, their rig.

Blowing Out RV Water Lines vs Using Antifreeze

There are a couple of different ways to winterize an RV. One involves pumping RV antifreeze into the RV’s water system. In our opinion, this isn’t ideal for a number of reasons, not the least of which is the unnecessary use of RV antifreeze (and the plastic containers it comes in). There’s also the issue of RV antifreeze sitting in your RV’s entire plumbing system for months. We use a non-toxic antifreeze, of course, but still – why use gallons of it every season if it isn’t necessary?

Another drawback of winterizing an RV using antifreeze is the need to DE-winterize when the warmer weather returns. In essence, this means going through the winterizing process in reverse, requiring both time and lots of water to thoroughly flush any residual antifreeze out of the system.

Those are some of the reasons why we prefer winterizing our RV with an air compressor.

However, we wouldn’t use just any air compressor. For example, we wouldn’t use a portable air compressor (the type with a tank (often referred to as a pancake compressor) because they can introduce oil or other contaminants into the fresh water system. They can also take up quite a bit of space.

Air compressor with tank. We would not use this type for winterizing an RV with an air compressor.

This type of air compressor has a tank that could introduce oil and other debris into your fresh water system.

What Do I Need to Winterize My RV With an Air Compressor?

If you’ve followed our full-time RV life for any length of time, you’ve probably learned that one of our favorite pieces of gear is our Viair 400P-RV portable air compressor. We’ve used this thing for YEARS (so we’re speaking from extensive experience), and we absolutely love it.

Not only is it tankless, but it also has a built-in air filter to prevent debris and contaminants from entering the system.

Sale

You may have seen our post last winter entitled “Which is the Best RV Air Compressor for You?” In that post, we looked at a number of air compressors and explained why we love our Viair 400P-RV so much.

But we waxed poetic about the 400P-RV long before that post. In fact, we used our Viair portable air compressor not only to fill the huge high-pressure tires on our 43-foot diesel pusher but also to winterize our plumbing system when we were planning to be away from the RV for a couple of months during the winter.

In order to accomplish the latter, we had to create our own little winterization kit for our Viair 400P-RV with a blow-out plug, an adjustable air pressure regulator, and male and female quick-connects. The system worked great, and we had a winning kit for winterizing our RV with an air compressor.

Viair must have seen our YouTube video demonstrating our winterizing kit, because not long after our video came out, they created one of their own just like it! This makes it easier than ever for anyone with a compatible Viair portable air compressor to winterize their RV using their air compressor, without having to make their own winterizing kit.

VIAIR 90145 RV Winterization Kit
  • This kit is to be used with Viair 400P-RV or 450P-RV models only.
  • 1/4” Quick Connect Coupler And Stud (M, NPT)

What You’ll Need:

To winterize your RV using an air compressor you’ll need an air compressor, of course, and you’ll also need a couple of other items.

If you have a Viair compressor that’s compatible with the Viair winterizing kit, you’ll only need the compressor and kit, as well as a couple of gallons of RV antifreeze (yes, there are still a couple of places you’ll want to use that… just not throughout the system).

If you don’t have a Viair air compressor and winterization kit, you’ll need the following:

How Do You Winterize an RV with Compressed Air?

We’re glad you asked! Here are the basic steps to follow to winterize your RV using an air compressor. Your RV may be different from ours, so the procedure may need to be adjusted accordingly.

The day before you plan to winterize, open the fresh water tank’s low point drain and shut off the propane and the electricity to the water heater.

On the day you’re going to winterize your RV:

  1. Dump and flush your black and gray tanks. (Following our video instructions here.) Leave the gray valve open and your sewer hose connected when finished.
  2. Disconnect the city water supply and turn off your RV’s water pump.
  3. Open the pressure relief valve on your RV’s water heater, and remove the drain plug or anode rod.
water heater's pressure relief valve and drain plug or anode rod

First, open the pressure relief valve. Then remove the drain plug (Atwood heaters) or anode rod (Suburban heaters). Stand out of the way and be prepared for water to flow out of the water heater.

  1. Using a tank rinsing wand, flush your RV’s water heater to clean out any loose scale and debris. If you’d like to watch our step-by-step DIY tutorials on water heater tank cleaning, you’ll find the Atwood video here, and the Suburban video here (with an important follow-up about anode rods here).
  2. Attach the blow-out plug. For RV’s with a typical fresh water connection, you’ll attach the blow-out plug directly to the water connection. For RV’s with a permanent hose on a reel like ours, you’ll attach the blow-out plug to the end of the hose.
fresh water connection port

Attach your blow-out plug directly to your fresh water connection, (or directly to your hose if your RV has a permanent built-in hose).

  1. Set the inline air pressure regulator to a maximum of 45 PSI to ensure the pressure supplied by your air compressor doesn’t exceed the allowed limits on your RV’s plumbing (be aware, you MAY need to set it lower… not all RV plumbing can withstand 45 PSI)
  2. Connect your compressor to a power source and turn it on.
  3. Close the pressure relief valve on your water heater and pull the trigger of your air compressor wand. It’s not important to get every drop of water out of the water heater. The important piece is draining all the water from the lines leading into and out of it. Give the wand an extra squeeze or two until there is just a trickle of water coming out of the heater.
  4. If you have a Suburban brand water heater, then you have an anode rod that you removed to drain the water heater. Depending on the condition of the anode rod, this may be a good time to replace it.
old and new anode rods for Suburban water heaters

The anode rod on top has served its sacrificial purpose well and is ready to be replaced with the new anode rod on the bottom. It might have enough material on it to make it another year, but they’re cheap insurance, so why risk your water heater’s tank?

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Suburban 232767 Water Heater Anode Rod
  • Magnesium anode rod
  • For use in RV water heaters
  1. Reinstall your drain plug or anode rod using plumber’s tape (wind several wraps around the threads). Tighten into place.
  2. Turn your water heater bypass valves to the bypass position.
water heater bypass valve closed to bypass water heater while winterizing RV with air compressor

Your water heater’s bypass valves allow you to bypass the water heater when winterizing the RV.

  1. If you have a whole-house water filter, unscrew the housing, discard the water filter, empty the remaining water out, and reinstall it without a filter.
  2. Open the hot and cold low point drains of your RV.
  3. Turn on every faucet in the RV set to “warm” to allow all water to easily run out through the low point drains.
  4. If you have a water filter under your sink or an ice maker, turn the bypass valves and remove and discard the filter(s). Instead of a bypass valve, some RVs come with a short length of tubing, which takes the place of the discarded filter during storage.
  5. When water is no longer running out of the low point drains, close the valves and turn off all the faucets in your RV.
  6. Turning on one faucet at a time set to “warm” to open both hot and cold lines at the same time (or each side separately if you prefer… that works, too!), blow compressed air through the system one or two times until the water clears out of the faucet. If you don’t have a helper inside the RV to monitor this for you, a couple of 15-second blasts or 30 seconds total should blow the water line out sufficiently. Repeat this process at every faucet, and don’t forget your showerhead, kitchen sprayer, water dispenser, toilet, and toilet sprayer if you have one.
  7. Check your manufacturer’s instructions for draining your ice maker if you have one.
  8. If you have a dishwasher and/or washing machine, turn them on, blow out the lines, then shut them off. Follow any additional steps recommended by the manufacturer for RV winterizing. If your RV is pre-plumbed for a washing machine but you don’t have one, you still have to blow out the lines. Open each side one at a time and have a bucket or pitcher handy to catch any water that sprays out as you do so.
  9. Pour a cup or two of RV antifreeze into each of your RV’s sink drains to protect the p-traps from freezing. Don’t forget the shower drain.
RV antifreeze for winterizing RV with an air compressor

Pouring a little non-toxic RV antifreeze in all of your RV’s p-traps and in the toilet is part of the winterization process.

  1. Pour about two cups of antifreeze into the toilet and flush it. Pour two more cups or so of antifreeze into the toilet and leave it there.
  2. To protect our water pump from freezing, we pump it dry. To do this, we turn on our outdoor shower and our water pump and run the shower for about 15-20 seconds. Don’t run it dry for too long or you could risk damaging the water pump.
  3. Blow the remaining water out of the outdoor shower with the air compressor.
blowing the remaining water out of the outside shower while winterizing an RV with an air compressor

Use the air compressor to blow the remaining water out of the outdoor shower.

  1. To clear water from the fresh tank fill line, turn the “tank fill” valve on and blow it out. This will blow a small amount of water into the fresh tank, but that’s not a problem, and nothing to worry about.
  2. With a backflow preventer inline, we attach the air compressor to the black tank flush and blow it out as well.
  3. Close the fresh water low point drain.
  4. Close the gray valve.
  5. Detach your RV sewer hose and store it for the winter.
  6. Open all faucets in the RV and leave them open.

If you’d like a clearer picture of the entire procedure, watch our video below for step-by-step visuals of the entire process!

Conclusion

If winterizing your RV with an air compressor is in your plans this year, we hope this information will prove helpful to you as you navigate the process of winterizing your RV’s plumbing system.

Remember, when in doubt (or when you see something that’s different from what you see on our RV), check your owner’s manual for the recommendations of your RV’s manufacturer.

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Frank G.

Wednesday 26th of October 2022

Being this the 1st year RVing, I have really appreciated your video’s and articles. I took your recommendation for Winterizing with an air compressor, even purchasing the 400P Viair & Winterizing Kit! I have a question about blowing out the Black Tank Flush Line. There is no mention of opening anything, how/where does the compressed air escape?

TheRVgeeks

Thursday 27th of October 2022

Good question, Frank. We didn't mention opening anything when blowing out the black tank flush because there isn't anything you need to do. The air entering the black tank through the flush system will just vent out through the roof vent. No worries about the black tank getting pressurized.

Dan H.

Saturday 3rd of September 2022

Hi Guys: Our 2017 Dutch Star has a compressed air port under the hood near the Onan generator. Is using this compressed air for winterizing not a good idea?

TheRVgeeks

Saturday 3rd of September 2022

Hi Dan! We have one of those ports as well. We're pretty sure every diesel pusher has one, because if they ever need to be towed, the tow truck has to bridge an air line over to the rig to keep the system aired up so the parking brakes stayed released. You CAN use that air to winterize, but we prefer not to use any compressor with a tank (like those common pancake compressors, or the one on the RV itself). That's due to the potential for any tank-style compressor to blow sediment, oil, or other contaminants into our fresh water system. The Viair is tankless, and even has a filter on the inlet to prevent it from getting debris into it, so it's an assured source of clean pressurized air. Again, not that it's a huge risk that the RV's compressor would contaminate our water system. But we just like to be extra careful since we drink the water from our fresh tank (through our Acuva water purifier to kill any bacteria). Hope this helps explain our thinking. Always great to hear from a fellow Newmar owner!

Rich T.

Monday 28th of February 2022

Hi - I have a question about the photo of the red pancake compressor you suggest not using. There is a very popular "oil free" version of this same Craftsman compressor I've just ordered after seeing it recommended in some other RV blogs as one that does NOT introduce oil and dirt into water lines. Were you aware that there is an oil free version or do you have other issues with this specific one? I appreciate your blog as I'm getting up to speed on things.

TheRVgeeks

Monday 28th of February 2022

Hi Rich! We've seen those types of tanks before. Even though they describe themselves as "oil-free" we do have some concern about any compressor that uses a tank when it comes to blowing out fresh water lines. Any time there's a tank, there's potential for sediment or other contaminants to build up. We know the Viar compressor we use is more expensive, but the dual benefits of no tank, and smaller size (an important consideration, especially for us full-timers) has us making the investment in tankless.

McLawhon George

Thursday 3rd of February 2022

Silly question but which way does the air pressure regulator arrows go?

TheRVgeeks

Sunday 6th of February 2022

Hi George! The arrows follow the direction of flow, so point them from the air compressor to the RV.

Bill Thompson

Sunday 10th of October 2021

Hey guys. The husband and I will be putting our 2016 Newmar Ventana LE to bed this winter for the first time here in St. Louis. We got her this past April and have really enjoyed the insight you both provide to RV newbies like us. The winterization piece I don't understand is how does one blow out the ice maker line to make sure there is no water left on the other side of the inlet valve. I like your process better than antifreeze but was initially gonna make ice until we got pink or yellow ice cubes to be sure from the antifreeze in the lines. This is the last piece I need to understand before winterization. Any insight would be awesome. Thanks for all you do and always look forward to your posts.

TheRVgeeks

Sunday 10th of October 2021

Hey Bill. Congrats on the new Ventana! Glad to hear you've been out enjoying! The ice maker is a bit of a sticking point in the winterization process... and it depends on if you have an RV fridge (propane/electric) or a residential fridge. And whether or not you have an inline water filter that feeds the ice maker. Taking the second part first, you need to remove and bypass the water filter under the fridge (assuming your 2016 Newmar isn't too different than our 2005, Newmar's filter setup includes bypass valves you can turn to prevent water, or in this case air, from going through the filter). Once bypassed, you'll want to remove the filter and drain it. You can replace it in the Spring so you'll have fresh clean water for your ice.

If you have a residential fridge, it's likely that there's a means of triggering the ice maker to cycle (on ours, there's a tiny little button underneath the front edge of the ice maker that, when pressed, triggers it to run a cycle). Takes two people, but you can then trigger the ice maker to cycle while you're blowing out the lines. You'll want to do it a couple of times to be sure you get it all out.

For an RV fridge, there's not typically a way to trigger an ice-maker cycle. But you should have access to the BACK of the refrigerator through the vent in the sidewall of the RV. From back there, you can access the water line for the ice maker and you should be able to disconnect it and drain that line out. When you do, water may dump onto the ice trays in the freezer since the "suction" in the line will be broken. You'll probably want to also leave the compressor hooked up with the water lines pressurized with air to let the ice maker cycle once or twice. That way, air will blow through the solenoid valve on the back of the fridge, making sure there's not water left in there that could freeze and damage it.

It's all a bit of a pain, but worth it in the long run.

Hope this helps!

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