Fullport Backwater Valve Installation Tips
RETROFIT INSTALLATION - How to install your backwater valve
A backwater valve may fail to protect if there is a back-grade (flat or negative slope) through the valve. In order to achieve a minimum slope of 2% through the valve in a retrofit installation, the installer will most likely need to expose up to 4 or 5 feet of pipe.
Many sewers are flat or back-graded and additionally, there is a 3/4" difference in height from inlet to outlet on a Mainline Fullport Backwater Valve. It may be necessary to adjust the grade on the piping leading up to the valve to achieve the required slope through the backwater valve.
Note: Our other style valve (the Adapt-A-Valve) designed for direct earth burial outside of the foundation may require excavation of up to 10' of run.
4963 ABS or PVC Backwater Valve Installation Sticker
This is a copy of the 4-1/4" X 4-1/2" adhesive-backed sticker included with each Mainline 4963 ABS or PVC Backwater Valve we sell that should be affixed in a visible spot near the backwater valve installation.
This is a copy of "Installer Notes" written on the peel-off backing of the adhesive-backed Backwater Valve sticker depicted above.
Mainline Fullport Backwater Valves are designed to be virtually maintenance free. However, they are mechanical devices sitting in a sewage environment, and periodic inspections are required.
To ensure the satisfactory performance of the backwater valve follow the procedures listed below.
1. Remove the cleanout plug on the top of the valve and do a visual inspection.
On models fitted with closed cell polyethylene floats, check the condition of floats and replace as necessary.
Note: these floats are located on both sides of the gate and are protected from sewage contamination by the sidewalls of the gate and body (longlife cycle, impervious to sewage). CSA certified floats.
If damage is found on the gate, or a more thorough cleaning of the valve is required, remove the bolted cover. Important: if you have difficulty maintaining these backflow devices, contact your plumber.
More information may be available from the manufacturer's website at www.backwatervalves.com
Also Review this page with images of the inside of the 4963 Backwater valve
Back to the Frequently Asked Questions page
Mainline Fullport Backwater Valves offer the right solution for your sewer backup problems. SPECIAL OFFER: Mainline Backwater Valve "Combo" with Access Box ($89.00 value if purchased separately) Valves without Access Box are also available with a slight shipping discount in the price.
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Be sure to check with the plumbing authority in the municipality in which your valve is to be installed to insure that your installation is in compliance with local code, and be sure have your valve inspected by your local plumbing inspector after installation. Inspect your valve frequently; the Backwater Valve through its clear plastic housing top, and the Adapt-A-Valve, by removing the gate cassette.
Pipe end-to-end, the Adapt-A-Valve takes up 6" of run in your line and the outlet is 1-1/2" LOWER than the inlet, so in just 6" the level of the pipe at the outlet side needs to be 1-1/2" lower.
Pipe end-to-end, the Backwater Valve takes up 12" of run in your line and the outlet is 3/4" LOWER than the inlet, so in just 12" the level of the pipe at the outlet side needs to be 3/4" lower.
Depending upon the amount of slope in your line (2% minimum is required for proper operation), you may need to replace several feet of pipe downstream from the valve to average out this "loss" of fall.
NOTE: New Straight-Fit and ML-FR4 require less slope. (refer to detail pages for these products)
Mainline Valve Warranty
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