Is your RV water pump turning on and off every time you open the faucet just a little bit? That rapid “chattering” noise is not only annoying but can also wear out your pump motor prematurely. You are likely missing a crucial component or have installed it incorrectly. This guide provides detailed Shurflo 3400 Accumulator Tank Plumbing Installation Instructions U Tube to help you stabilize your water pressure and enjoy a quiet, efficient plumbing system.
Many RV owners struggle with this specific setup because the concept of an accumulator tank can seem counterintuitive. However, once installed correctly, it acts as a shock absorber for your water lines. In this article, we will break down the process step-by-step, ensuring you get it right the first time.
What Is a Shurflo 3400 Accumulator Tank and Why Do You Need It?
Before we dive into the wrenches and pipes, let’s understand what we are installing. The Shurflo 3400 series pumps are popular in recreational vehicles for their reliability. However, like all positive displacement pumps, they operate in an “on/off” cycle.
Without an accumulator, every time you turn on a tap, the pump kicks on immediately. When you close it, the pump stops instantly. This causes:
- Pressure Surges: Known as “water hammer,” which can damage joints.
- Motor Wear: Frequent starting draws high amperage and heats up the motor.
- Noise: The constant clicking is disruptive, especially at night.
An accumulator tank contains a rubber bladder pre-charged with air. As the pump runs, it fills the tank with water, compressing the air. When you open a faucet, the compressed air pushes the water out, allowing the pump to stay off longer. This results in smoother flow and fewer cycles.
Understanding the “U-Tube” Configuration in Plumbing
The term “U-Tube” in the context of Shurflo 3400 installation often refers to the physical layout of the piping between the pump and the accumulator. While some installers use a direct straight line, creating a slight loop or using flexible tubing in a U-shape can offer distinct advantages.
Why Use a U-Shaped Loop?
- Vibration Dampening: A rigid straight pipe transfers pump vibration directly to the tank and chassis. A U-shaped section of flexible hose acts as a natural dampener.
- Thermal Expansion: RVs experience significant temperature changes. A U-loop allows for minor expansion and contraction of the plumbing without stressing the fittings.
- Serviceability: It creates a bit of slack, making it easier to remove the accumulator for maintenance without cutting pipes.
Pro Tip: Ensure the “U” does not create a low point where water can trap and freeze if you are winterizing your RV. Always ensure the system can be fully drained.
Step-by-Step Shurflo 3400 Accumulator Tank Plumbing Installation Instructions U Tube
Follow these instructions carefully. Safety first: always disconnect the 12V power to your water pump before beginning any plumbing work.
Tools and Materials Needed
- Shurflo 3400 Accumulator Tank (or compatible generic)
- 1/2-inch PEX tubing or flexible braided stainless steel hoses
- Two 1/2-inch shut-off valves (ball valves recommended)
- Teflon tape or pipe thread sealant
- Adjustable wrenches
- Pipe cutter
- Hose clamps (if using barbed fittings)
Step 1: Locate the Ideal Position
Find a spot near your water pump. The accumulator should be installed on the output side of the pump (the side going to the faucets), not the input side from the fresh water tank. Ensure there is enough clearance to access the air valve on top of the tank later.
Step 2: Install Shut-Off Valves
It is highly recommended to install shut-off valves before and after the accumulator.
- Cut the existing output line from the pump.
- Install a tee fitting if necessary, or replace the straight section with two ball valves with a gap in between.
- This allows you to isolate the accumulator for servicing without draining the entire RV water system.
Step 3: Create the U-Tube Connection
This is where we implement the Shurflo 3400 Accumulator Tank Plumbing Installation Instructions U Tube strategy.
- Measure the distance between the output valve and the accumulator inlet.
- Cut your flexible tubing slightly longer than needed to allow for a gentle “U” shape or loop.
- Connect one end to the pump-side valve.
- Route the tube in a smooth U-curve. Avoid sharp kinks that restrict flow.
- Connect the other end to the accumulator tank inlet.
Note: If using rigid PEX, use elbow fittings to create the U-shape, but flexible braided hoses are superior for vibration reduction.
Step 4: Secure the Tank
Mount the accumulator securely using the provided bracket or sturdy zip ties. It must not vibrate against the wall or floor. A vibrating tank can loosen fittings over time.
Step 5: Check for Leaks
Turn on the city water connection or fill your fresh tank. Turn on the pump manually (bypassing the pressure switch if possible, or just opening a faucet). Check all connections for drips. Tighten as necessary.
Pre-Charging the Accumulator: The Critical Step
Most installation failures occur here. An accumulator tank comes with a rubber bladder inside. You must add air to the outside of the bladder before putting water in.
- Ensure the system is depressurized. Open a faucet to release any water pressure.
- Locate the air valve. It looks like a standard tire valve stem on the top or side of the tank.
- Check current pressure. Use a tire gauge. It is likely empty.
- Add Air. Use a bicycle pump or air compressor. Add air until the gauge reads 20–25 PSI.
- Why this pressure? Your pump’s cut-out pressure is usually around 40–50 PSI. The accumulator needs to be charged to roughly half of that to function effectively.
- Do not over-inflate. If you go above 40 PSI, the pump may never turn on because the tank pressure equals the system pressure.
For more technical details on fluid dynamics in plumbing systems, you can refer to general engineering principles on Wikipedia.
Troubleshooting Common Issues
Even with perfect Shurflo 3400 Accumulator Tank Plumbing Installation Instructions U Tube adherence, issues can arise. Here is how to fix them.
| Issue | Possible Cause | Solution |
|---|---|---|
| Pump still cycles rapidly | Low air charge in tank | Check air pressure with a gauge. Recharge to 20-25 PSI. |
| Water leaks from air valve | Ruptured bladder | The internal rubber bladder has failed. Replace the accumulator tank. |
| No water coming out | Valve closed or blocked | Check that both shut-off valves are fully open. Inspect the U-tube for kinks. |
| Air sputtering from faucets | Too much air or loose fitting | Bleed the system by running all faucets until water flows steadily. Check fittings. |
FAQ Section
1. Can I install the accumulator on the input side of the pump?
No. The accumulator must be installed on the pressure side (output) of the pump. Installing it on the suction side (input) will not prevent pump cycling and may cause cavitation issues.
2. How often do I need to check the air pressure?
It is good practice to check the air pressure once a year, preferably before your main camping season. Air can slowly permeate through the rubber bladder over time, causing the pressure to drop.
3. Does the U-Tube configuration affect water flow rate?
If installed correctly with proper diameter tubing (minimum 1/2 inch), a U-tube has negligible impact on flow rate. In fact, by reducing turbulence and vibration, it may improve the longevity of your plumbing connections.
4. My accumulator is hot to the touch. Is this normal?
Slight warmth is normal due to friction and ambient heat. However, if it is too hot to touch, there may be a blockage downstream causing excessive pressure buildup, or the pump is running continuously due to a leak. Turn off the system and investigate immediately.
5. Can I use a generic accumulator instead of Shurflo?
Yes. As long as the accumulator is rated for potable water and has a similar volume (usually 1–2 liters for RVs), it will work. Just ensure the fittings match your plumbing size.
6. What happens if I forget to pre-charge the tank with air?
If you fill the tank with water without adding air first, the bladder will be pressed against the tank walls. The tank will act like a solid pipe segment, providing zero cushioning effect. You must drain the water, add air, and then repressurize the system.
Conclusion
Installing an accumulator tank is one of the most impactful upgrades you can make to your RV’s water system. By following these Shurflo 3400 Accumulator Tank Plumbing Installation Instructions U Tube, you ensure a quieter, more efficient, and longer-lasting plumbing setup. The key takeaways are: install on the output side, use a flexible U-loop for vibration control, and never forget to pre-charge the air bladder to 20–25 PSI.
Don’t let a chattering pump ruin your camping tranquility. Take a weekend afternoon to perform this installation, and enjoy the smooth, silent water flow on your next trip.
Did you find this guide helpful? Share it with your fellow RV enthusiasts on Facebook or Pinterest to help them silence their pumps too! If you have any questions about your specific setup, leave a comment below.
Leave a Reply