1. Product Overview
The Moen M-Dura Posi-Temp Shower Trim Kit, model T8370CBN, is a commercial-grade 7-inch classic shower valve control trim kit designed for durability and consistent performance. This trim kit features heavy-duty all-metal construction with a brushed nickel finish, offering corrosion resistance for a long-lasting and reliable shower fixture.
It is built on the Moen M-PACT common valve system, which allows for future updates to the shower valve handle without requiring plumbing replacement. The Posi-Temp valve system (sold separately) helps eliminate sudden temperature changes caused by pressure fluctuations in the water supply.
Figure 1: Moen M-Dura Posi-Temp Shower Trim Kit T8370CBN, Brushed Nickel finish.
2. Setup and Installation
This trim kit requires a Moen Posi-Temp valve, which is sold separately. Compatible valve models include 8370HD, 8371HD, 8372HD, 8373HD, 8374HD, or 8375HD. Ensure you have the correct valve before proceeding with installation.
2.1 Components Included
The Moen M-Dura Posi-Temp Shower Trim Kit includes the following components:
- Handle and Plug Button
- Escutcheon Assembly
- Installation Hardware
- Detailed Installation Instructions (paper manual)
Figure 2: Included components: Handle, plug button, escutcheon, and installation hardware.
2.2 Required Valve (Sold Separately)
The trim kit is designed to work with Moen Posi-Temp valves. These valves accommodate standard ½” connections and are available with various connection options including CC (copper), CPVC, crimp ring PEX, cold expansion PEX, and IPS (threaded). Ensure the correct valve type is selected for your plumbing system.
Figure 3: Example of a Moen Posi-Temp Valve, which is required and sold separately.
2.3 Pre-Installation Steps
- Before installing the decorative trim, set the maximum temperature limit on your Posi-Temp valve according to local codes and personal preference.
- Refer to the detailed installation instructions included with your trim kit for specific steps and diagrams.
2.4 Identifying a Moen Posi-Temp Valve
To confirm you have a compatible Moen Posi-Temp valve, observe the handle operation. Posi-Temp valves feature a handle that rotates only to control both water flow and temperature. There is no separate pull-out function for flow control.
Figure 4: Diagram illustrating the escutcheon and handle operation for a Moen Posi-Temp valve, which is rotate-only.
3. Operating Instructions
The Moen M-Dura Posi-Temp Shower Trim Kit is designed for simple and intuitive operation in both shower and tub applications. The single handle controls both water temperature and flow.
3.1 Temperature and Flow Control
- To turn on the water and adjust temperature, rotate the handle.
- Typically, rotating the handle counter-clockwise from the 'off' position (often indicated by a blue dot or cold marker) will increase water flow and temperature towards warm.
- Continue rotating towards the 'hot' position (often indicated by a red dot or hot marker) for warmer water.
- To decrease temperature, rotate the handle back towards the 'cold' position.
- To turn off the water, rotate the handle fully to the 'off' position.
The Posi-Temp valve maintains consistent water temperature by balancing incoming hot and cold water pressure, preventing sudden temperature changes (shower shock).
4. Care and Maintenance
Proper care and maintenance will ensure the longevity and appearance of your Moen M-Dura Posi-Temp Shower Trim Kit.
4.1 Cleaning Instructions
- Clean the brushed nickel finish with a soft, damp cloth.
- Avoid abrasive cleaners, harsh chemicals, or scouring pads, as these can damage the finish.
- For water spots, a mild soap solution or a vinegar-water mixture can be used, followed by rinsing and drying with a soft cloth. The corrosion-resistant design helps minimize spotting.
4.2 General Care
- Regularly inspect the trim kit for any loose components and tighten as necessary.
- If you experience issues with water flow or temperature control, consult the troubleshooting section or contact Moen customer support.
5. Troubleshooting
This section addresses common issues you might encounter with your Moen M-Dura Posi-Temp Shower Trim Kit.
5.1 Handle Not Seating Properly / Sticking Out
If the handle does not sit flush or the center screw does not engage correctly during installation, ensure the Posi-Temp retaining pin within the valve body is fully seated. If the retaining pin is not completely in, the center post of the trim kit may not slide all the way into the valve. Gently tap the retaining pin down until it is fully inserted, then reassemble the trim kit.
5.2 Inconsistent Water Temperature
The Posi-Temp valve is designed to prevent sudden temperature changes. If you experience inconsistent water temperature, verify that the hot and cold water supply lines to the valve are fully open. If the issue persists, the valve cartridge may need inspection or replacement. Consult a qualified plumber or Moen customer support.
5.3 Low Water Flow
Low water flow can be caused by several factors:
- Clogged Showerhead: Remove and clean the showerhead for mineral deposits.
- Partially Closed Shut-off Valves: Ensure the main water supply and any in-line shut-off valves are fully open.
- Valve Cartridge Issue: A worn or faulty valve cartridge can restrict flow. This may require professional inspection.
6. Specifications
| Feature | Specification |
|---|---|
| Brand | Moen |
| Model Number | T8370CBN |
| Color | Brushed Nickel |
| Material | Metal |
| Finish Type | Brushed |
| Number of Handles | 1 |
| Mounting Type | Wall Mount |
| Head Size (Trim Plate Diameter) | 7 inches |
| Compatible Valve System | Moen Posi-Temp (Valve sold separately) |
| UPC | 026508235669 |
7. Warranty Information
The Moen M-Dura Posi-Temp Shower Trim Kit is backed by Moen’s Limited Lifetime Warranty. This warranty covers defects in material and manufacturing workmanship under normal use. For specific details regarding warranty coverage, terms, and conditions, please refer to the official Moen warranty documentation included with your product or visit the Moen website.
8. Customer Support
For further assistance, technical support, or to inquire about replacement parts, please contact Moen Customer Service. You can find contact information on the official Moen website or in the installation instructions provided with your product.
Please have your product model number (T8370CBN) and purchase date available when contacting support.
