This is step by step description and photos for winterizing your camper.  This is brought to us by He Ruide, a very active camper and forum community member.
Your camper maybe a little different but the overall steps should help.
Purging the lines

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Home made Blow Out plug. Remember the water pressure regulator will protect the lines from over pressure.
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Attach the Air Chuck/Blow Out Plug and water pressure regulator to the PUP. Then open all the water valves (sink, shower, outside hose and drain valves). Note some folks stop after this point as they assume there is no water in the lines anymore.
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To ensure that all the lines are free of water you can use an air compressor to blow out the water lines.
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You can make your own blow out plug by using a water pressure regulator, 3/4 MH x 1/2 FIP, a 1/2 Male pipe to 1/4" PIP hex bushing and a male quick release air hose connection. Note - I used my water pressure regulator to prevent over pressure since I did not have an air regulator on my tank.
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Attach an Air Chuck with a clip. This is needed if you are blowing out the water by yourself as it attaches to the Blow Out Plug and keeps a constant flow of air.
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In order to connect the air compressor to the popup up or hybrid you'll need a "Blow out Plug"
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