Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your Gerber Flushmate III 503 Pressure Assist Unit, model M-101526-F3. This unit is specifically designed for 2-piece toilets that are already equipped with Flushmate technology. It is important to note that this product is not a retrofit unit and is intended only for Flushmate-specific toilets.

Image of the Gerber Flushmate III Pressure Assist Unit, model M-101526-F3, showing its compact design and internal components.
Safety Information
CAUTION: PRESSURE VESSEL
To prevent injury, always turn off the water supply and flush the unit to relieve pressure prior to servicing. Use cold water only. Do not use chemical disinfectants or corrosive household cleaners within the china tank and Flushmate unit, as these chemicals will damage the system and void the warranty.
Product Overview
The Flushmate III Pressure Assist Unit is a self-contained system that uses water line pressure to compress air within a sealed vessel. When the toilet is flushed, this compressed air forces water into the bowl, resulting in a powerful and efficient flush. This design helps to conserve water and maintain a cleaner toilet tank environment.
Setup and Installation
This unit is designed for straightforward installation in compatible 2-piece toilets. Please ensure your toilet is specifically designed for a Flushmate III system before proceeding. This is not a universal retrofit product.
Required Tools:
- Wrench for 3-inch diameter plastic nuts (specialized tool may be required)
- Common hand tools (e.g., adjustable wrench, screwdriver)
Installation Steps:
- Prepare the Toilet: Turn off the water supply to the toilet. Flush the toilet to empty the tank and relieve any remaining pressure in the Flushmate unit.
- Remove Old Unit (if applicable): Carefully disconnect the water supply line and any mounting hardware securing the old Flushmate unit.
- Install New Unit: Position the new Gerber Flushmate III unit into the toilet tank. Ensure it aligns correctly with the tank's mounting points.
- Secure the Unit: Fasten the unit using the provided hardware. Tighten all connections securely to prevent leaks. Pay special attention to the large plastic nut, ensuring it is snug but not overtightened.
- Connect Water Supply: Reconnect the water supply line to the Flushmate unit.
- Restore Water Supply: Slowly turn on the water supply to the toilet. Check for any leaks around the connections.
- Test Flush: Perform several test flushes to ensure proper operation and to check for any leaks or issues.
If you encounter any difficulties, refer to the troubleshooting section or contact customer support. Online video tutorials can also be a helpful resource for visual guidance.
Operating Instructions
The Gerber Flushmate III Pressure Assist Unit operates automatically once installed. Simply press the flush handle as you normally would. The unit will utilize the incoming water pressure to create a powerful flush, effectively clearing the bowl while using less water than traditional gravity-fed systems.
The pressure assist system ensures a consistent and strong flush, contributing to a cleaner toilet bowl and reducing the likelihood of clogs.
Maintenance
Regular maintenance helps ensure the longevity and optimal performance of your Flushmate III unit.
- Cleaning: The sealed design of the Flushmate unit helps keep the toilet tank clean, minimizing the buildup of mold and mildew. Avoid using in-tank chemical cleaners, as they can damage the unit and void the warranty.
- Sponge Seal: If you experience water leaking or the unit not sealing properly, inspect the sponge seal. Ensure that the correct type of seal is used. Some users have reported that a soft green sponge seal is necessary for proper function, while a hard black seal may cause water to escape the tank during flushing. If replacing, ensure you obtain the appropriate seal for your specific Flushmate model.
- Periodic Inspection: Periodically check all connections for tightness and signs of wear.
Troubleshooting
If you encounter issues with your Flushmate III unit, consult the following common problems and solutions:
| Problem | Possible Cause / Solution |
|---|---|
| Persistent Water Running: | This often indicates a seal issue or a problem with the fill valve. Check the sponge seal for proper seating and condition. Ensure the fill valve is not obstructed and is closing completely. |
| No Pressure / Weak Flush: | The pressure assist cartridge might be faulty or worn out. Ensure the water supply is fully open. If the problem persists, the cartridge may need replacement. |
| Water Leaks from Tank (during flush): | This is typically due to an improper or damaged sponge seal. Verify that the correct soft green seal is installed and is not hardened or cracked. Replace if necessary. |
| Unit Does Not Fit / "Reverse Inlet": | Even with the correct model number, variations can occur. Double-check the orientation and ensure all components are correctly aligned. If it's a significant design difference, verify the exact model compatibility with your toilet. |
If these troubleshooting steps do not resolve the issue, please contact Gerber customer support for further assistance.
Specifications
- Manufacturer: Gerber
- Part Number: 99-413
- Model Number: M-101526-F3
- Item Weight: 1 pound
- Package Dimensions: 17 x 16 x 7 inches
- Batteries Required: No
- Batteries Included: No
- ASIN: B005CIS1QA
- First Available Date: April 12, 2015
Warranty Information
For specific warranty details regarding your Gerber Flushmate III Pressure Assist Unit, please refer to the warranty card included with your product or visit the official Flushmate website. Keep your proof of purchase for warranty claims.
Support
If you have questions or require technical assistance, please contact Flushmate customer support:
- Phone: 1-800-533-3450
- Phone: 1-248-446-5300
- Website: http://www.flushmate.com





