Product Overview
This manual provides detailed instructions for the installation and maintenance of the Wellmate Pentair Air Cell/Bladder Replacement Kit. This kit is designed to replace the internal air cell/bladder in compatible Wellmate pressure tanks, specifically the WM-6 model. It includes the air cell, O-rings, washers, and necessary instructions for a successful replacement.
The replacement air cell is made from durable, heavy-gauge engineered polymer, ensuring reliable performance. This kit is compatible with both Quick Connect and Classic model tanks, provided they are the newer "gray" colored tanks, not the older "yellow" models.
Figure 1: Exploded view of a Wellmate pressure tank, highlighting the seamless, full-size, blow-molded polymer air cell and its durable interior construction. The diagram also points out the high-density polyethylene inner shell and the high-impact PVC bottom inlet/outlet assembly.
Safety Information
- Always disconnect power to the well pump before beginning any work on the pressure tank system.
- Depressurize the system completely before opening the tank. Open a faucet to relieve pressure.
- Wear appropriate personal protective equipment (PPE), such as safety glasses and gloves.
- Ensure the work area is well-lit and clear of obstructions.
- If you are unsure about any step, consult a qualified professional.
Tools Required
- Adjustable wrench or pipe wrench
- Valve stem removal tool (similar to those used for bicycle tires)
- Utility knife or scissors
- Bucket for draining water
- Thread sealant tape (Teflon tape)
- Flashlight (optional, for internal inspection)
Setup and Installation
Replacing the air cell can take a couple of hours. It is recommended to have a second person assist with certain steps, especially when removing the old bladder and inserting the new one.
- Prepare the System:
- Turn off the power to the well pump at the circuit breaker.
- Open a nearby faucet to drain the pressure tank and relieve all system pressure. Allow water to drain completely.
- If possible, fill a few 5-gallon buckets with water before shutting off the main water supply for cleaning purposes during the installation.
- Disconnect the Tank:
- Disconnect the pressure tank from the plumbing system. For older tanks, it may not be necessary to completely remove the tank from the water supply line, but ensure enough clearance to work.
- Carefully move the tank to a suitable work area.
- Remove the Old Air Cell:
- Locate the air valve at the top of the tank. Use a valve stem removal tool to remove the valve core and ensure any remaining air pressure is released.
- Remove the bottom inlet/outlet assembly. This may require a pipe wrench.
- Carefully pull out the old air cell/bladder from the tank. This can be challenging and may require some maneuvering.
- Inspect the Tank Interior:
- Inspect the interior of the tank for any debris, rust, or sharp edges that could damage the new air cell. Clean as necessary.
- Install the New Air Cell:
- Unpack the new Wellmate air cell, O-rings, and washers.
- The most challenging part can be threading the string (often provided with the new bladder or you may need to use your own) from the bottom of the tank to the top to guide the new bladder into place.
- Carefully insert the new air cell into the tank, ensuring it is properly aligned and seated. Ensure the white nylon retainer is placed under the black rubber seal washer as part of the assembly.
- Reattach the bottom inlet/outlet assembly, applying thread sealant tape to ensure a watertight seal.
- Reinstall the air valve core at the top of the tank.
- Pressurize the System:
- Reconnect the tank to the plumbing system.
- Slowly open the main water supply valve to allow water to fill the tank.
- Once the tank is full, use an air compressor to pre-charge the air side of the tank through the air valve at the top. Refer to your tank's specifications for the correct pre-charge pressure (typically 2-4 PSI below the pump's cut-in pressure).
- Turn on the power to the well pump.
- Check for leaks and ensure the system is operating correctly.
Figure 2: Contents of the Wellmate Air Cell/Bladder Replacement Kit, showing the new air cell and the accompanying hardware for installation.
Operating Principles
The Wellmate pressure tank operates by using an air cell (bladder) to separate the water from the air charge. As water enters the tank, the air cell expands, compressing the air in the tank. This compressed air then pushes the water out when a faucet is opened, maintaining consistent water pressure and reducing pump cycling. The air cell prevents water from coming into contact with the tank walls, preventing corrosion and extending the tank's lifespan.
Maintenance
- Annual Air Charge Check: Periodically check the air pre-charge pressure in the tank (with the pump off and system depressurized). Adjust if necessary to maintain optimal system performance.
- Leak Inspection: Regularly inspect the tank and plumbing connections for any signs of leaks.
- Tank Compatibility: This replacement kit is specifically designed for newer "gray" Wellmate tanks. It is not compatible with older "yellow" tanks. Ensure your tank matches this requirement.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Pump short cycling (turns on and off frequently) | Low or no air pre-charge in the tank, or ruptured bladder. | Check air pre-charge and adjust. If water comes out of the air valve, the bladder is ruptured and needs replacement. |
| No water pressure or very low pressure | System not fully repressurized after installation, or air lock. | Ensure proper air pre-charge and allow pump to run to build pressure. Bleed air from plumbing lines if necessary. |
| New bladder seems too short for WM-12 tank | This specific kit (WM-6 / WM0075 PEU CH3133-2) is primarily designed for WM-6 tanks. While the product title lists other models, actual fit may vary. | Verify the exact model number of your tank and the replacement kit. If the bladder does not span the mount points, it is likely incompatible. Contact the supplier for the correct size. |
| Difficulty threading string for bladder installation | Common challenge due to tank design. | Patience is key. Try using a stiff wire or a vacuum cleaner to help guide the string through the tank. A second person can assist. |
Specifications
| Feature | Detail |
|---|---|
| Product Type | Air Cell/Bladder Replacement Kit |
| Brand | Wellmate / Pentair |
| Compatible Wellmate Tank Models | WM-6 (Primary compatibility). Also listed for WM-9, WM-12, WM-14WB, WM-20WB, WM23, WM-25WB, WM-35WB. Note: Verify exact fit for models other than WM-6. |
| Compatible Tank Color | Newer "Gray" colored tanks only (Not compatible with "Yellow" tanks) |
| Material | Buty Air Cell (Durable, heavy-gauge engineered polymer) |
| Kit Contents | Air Cell, Instructions, O-rings, Washers |
| Item Weight | Approximately 1 pound (0.45 kg) |
| Model Numbers (Kit) | CH3133-2, CH3134-2, CH3135-2, CH4466, CH4846 |
Warranty and Support
For specific warranty information regarding your Wellmate Pentair Air Cell/Bladder Replacement Kit, please refer to the documentation included with your purchase or visit the official Pentair website. Warranty terms typically cover manufacturing defects.
For technical support, troubleshooting assistance, or to inquire about compatible parts, please contact Pentair customer service or visit their official support portal. You can find more information and contact details on the Pentair Store on Amazon or their corporate website.
