Guide to Dewinterizing a Cirrus 620

This article applies to any Cirrus 620 equipped with the Nautilus P3, including the 2023, 2024, and 2025 models. Some drain valve locations may vary from model year to model year, but the core process will remain the same.

Introduction

Dewinterizing your nuCamp Cirrus 620 involves draining antifreeze, sanitizing the system, and flushing it with fresh water. Follow these steps to ensure your camper is ready for the camping season.

1. Drain the Antifreeze

Pull the gray lever to drain the gray tank.
Connect a sewer hose to prevent antifreeze from spilling into the compartment.
Repeat the process for the hot and cold drains and the freshwater tank drain.
Antifreeze will drain from underneath the camper.
Once fully drained, close all drain valves.

2. Prepare a Sanitizing Solution

Mix your sanitizing solution based on your preference.
A stronger solution can be immediately rushed, while a weaker solution will need to sit to sanitize effectively.
Recommended: 1/4 cup per 15 gallons. Let rest for 12 hours.
The video suggests 1/2 cup of bleach per gallon of water in a bucket. This can be immediately flushed.
Place one end of a hose into the solution and connect the other end to your Nautilus system.
Use the key on the sticker to set the Nautilus panel to Sanitize mode.

3. Siphon the Sanitizing Solution

Turn on the water pump to begin siphoning.
Once the system is pressurized, turn off the water pump.
Set the Nautilus panel to Dry Camping mode.

4. Flush the System with Sanitizing Solution

Inside the camper, turn on the water pump.
Run sanitizing solution through the kitchen faucet until water is clear (no pink antifreeze).
Repeat the process for the external shower.

5. Drain the System Again

At the Nautilus panel, turn off the water pump.
Empty the gray tank, hot and cold drains, and freshwater tank.
Close all drain valves once drained.

6. Refill the Freshwater Tank

Set the Nautilus panel to City Water mode.
Connect a garden hose to the City Water inlet.
Use an inline water pressure regulator to prevent over-pressurization.
Monitor the panel to avoid overfilling.
Switch the Nautilus panel back to Dry Camping mode.

7. Flush the System with Fresh Water

Turn on the water pump.
Run fresh water through the indoor sink and external shower to remove any residual sanitizing solution.
Turn off the water pump.
Open the drains again to remove any remaining water.

Final Step: Ready for the Camping Season

Your nuCamp Cirrus 620 is now dewinterized and ready for use! If you have any questions, contact tech@nucamprv.com.

Guide to Winterizing a Cirrus 620

Freezing climates can damage the camper’s plumbing system and equipment. The camper must be drained and have antifreeze protection before storing or camping in below-freezing temperatures in fall/ winter. This is done through a process called winterizing.

Be sure to always use a non-ethanol-based antifreeze when winterizing your camper.

When getting the camper ready for camping season in spring, you must cleanse the freshwater system to remove all the antifreeze. This process is called de-winterizing or sanitizing.

You may also find this step-by-step winterization video helpful.

While the Nautilus system instructions are generalized instructions, the following steps outline more detailed instructions for winterizing the freshwater & wastewater plumbing systems in your camper:

1. Drain Excess Water

Open the freshwater tank drain to release water.
Connect a sewer hose to your unit and pull the gray lever to drain the gray tank.
Once drained, close the gray tank valve.
Open the hot and cold water drain valves to release excess water.
Once drained, close the drain valves.
Under the sink, open the water heater drain and allow it to empty completely.
Once drained, close the water heater valve.
Ensure the cassette toilet is emptied before continuing.

2. Blow Out the Lines with Compressed Air

Materials Needed:

Short garden hose
RV blowout adapter
Air pressure regulator
Air compressor
A way to shut off airflow

Steps:

Thread the garden hose into the city water inlet on the Nautilus panel.
Set all Nautilus panel knobs to a 45-degree angle.
Ensure all faucets, fixtures, and drains are closed.
Open one low-point drain valve, keeping the other closed.
Turn on the air compressor (set below 40 PSI) and let air flow through.
Water will exit from underneath the camper.
Close the hot water low-point drain valve and open the cold water low-point drain valve.
Repeat the air compressor process for the cold water line.
Open the water heater drain and blow out the water heater line.
Once complete, close the valve back up.

3. Add Antifreeze to the System

Set the Nautilus panel to Winterize mode, following the key on the sticker.
Disconnect the hose from the air compressor and place it in the antifreeze container.
Ensure all faucets, fixtures, and drains are closed.
Turn on the water pump to begin siphoning antifreeze into the system.
When the lines are pressurized, move inside the camper.
Open the sink faucet until the water runs pink.
Press the button to fill the toilet with antifreeze and open the shutter valve.
Hook up the external shower hose to the Nautilus panel and run antifreeze through both hot and cold taps.
Disconnect the external shower hose and turn off the water pump.
Open the low-point drain valves for a few seconds to let antifreeze run through.
Antifreeze will exit from the bottom of the camper.

Final Step: Ready for Winter Storage

Your nuCamp Cirrus 620 is now properly winterized! If you have any questions, email tech@nucamprv.com.

Guide to the Nautilus P3 System

This article and video applies to any nuCamp model equipped with the Nautilus P3.

The Nautilus P3 system is used in the 2025 TAB 320, TAB 360, TAB 400, Cirrus 620, Cirrus 820, and Cirrus 920 models to streamline water management by centralizing essential functions. Below is an overview of its components, functions, and modes.

Step 1: Understanding the Nautilus Panel Components

The front panel of the Nautilus system includes the following key components:

City Water Hookup – Connects to city water for direct supply.
Black Tank Flush Hookup – Used to clean out the black tank by flushing it with fresh water.
Coax Connection for Interior TV – Provides a TV connection inside the camper.
Water Pump Switch – Turns on the water pump (identical to the interior pump switch).
External Shower – Allows access to hot and cold water outside the camper.
Mode Selection Knobs – Adjusts the system’s settings for different functions.
Instruction Key Sticker – Provides visual guidance on knob positions for each mode.

Step 2: Nautilus Panel Modes

1. Dry Camping Mode

Allows you to pump water from the freshwater tank to your fixtures.
Ensure the pump is turned on, either at the Nautilus panel or inside the camper.

2. Power Fill Mode

Used to fill the freshwater tank using a garden hose.
Connect the hose to the City Water Hookup and allow it to fill the tank.

3. City Water Mode

Directly supplies water from a city water connection to your fixtures, bypassing the freshwater tank.
No need to use the pump in this mode.

4. Sanitize Mode

Used when de-winterizing or sanitizing the system.
Connect a bucket or container to the City Water Hookup and siphon liquid into the fresh tank.

5. Winterize Mode

Used only during winterization to run RV antifreeze through the system.

Step 3: Using the Black Tank Flush

Connect the city water hose to the Black Tank Flush Hookup.
This allows fresh water to be forced through the black tank, helping flush out residual waste.

Important Notes:

Always use an inline water pressure regulator when connecting to city water (included in your welcome pack).
Follow the instructional sticker on the Nautilus panel for proper knob positioning.

An overview of your cassette toilet

Many nuCamp models have a 5-gallon cassette toilet. This includes the TAB 320, TAB 360, TAB 360 CS, and Cirrus 620. This may vary from model year to model year. Any model listed from 2021 to 2025 will have a cassette toilet.

The Thetford cassette toilet consists of two main parts:

A fixed portion (toilet inside the bathroom).
A removable waste tank (accessed from the exterior).

Using the Toilet

Flush Button – Press to activate the electric pump, which fills the bowl with water.
Handle – Open to release the valve blade and flush the toilet.
Level Indicator Display – A red light signals that the waste tank is full and needs to be emptied.

Accessing & Removing the Waste Tank

The waste tank access door is located on the driver’s side of the TAB 320.
Open the Seaflo access door to reach the tank.
To remove the tank:
1. Pull the safety latch to release the tank.
2. Slide the tank out using the grab handle and pull-out handle for easy transport.

Draining the Waste Tank

Take the tank to an authorized waste dump station. (For demonstration, water is being used instead of actual waste.)
Rotate the drain spout outward for easy and hygienic draining.
Remove the drain spout cap.
While tipping the tank forward, press the vent plunger on the back to improve airflow and prevent splashing.
Completely drain the tank.

Cleaning & Reinstalling the Waste Tank

Once emptied, replace the drain spout cap and return the spout to its normal position.
Slide the waste tank back into place until you hear an audible click, ensuring it is locked securely for transport.

Cleaning the Valve Blade

Remove the cover to access the valve blade and opener.
Spray cleaner inside the tank.
Rinse using the spout and valve blade opening.

Important Usage Tips

Do not drive with the tank more than three-quarters full.
For best performance, empty the tank completely before traveling.

Need Help?

If you have any questions, reach out to nuCamp Tech Support at tech@nucamprv.com.

Thank you and safe travels!

Using the Nautilus Water Management System in the Cirrus 620: A Complete Guide Print