- Home
- Floor Drains
- Round Trap Primer Drain

Trap Priming Floor Drain
Trap primer valves replenish evaporated water in floor drain P-traps to prevent toxic sewer gases and insect infestation. Don't hesitate to install them on any floor drain that isn't used regularly.
Standard features
- Top plate
- 12" square or round with solid cover
- Setting ring
- 12 GA, 2.5" below top plate
- Outlet sizes
- 2" · 3" · 4" · 6" · 8"
- Outlet pipe
- 4" long — Sch 10 or Sch 40
- Sump depth
- 6.25" or 10"
- Primer fitting
- Can be placed on the outlet pipe
Features
- Used in rooms where floors and drains are cleaned weekly or more
- T304 stainless
Drawings & documents
Need a drawing for your submittal? Request a detail drawing →
Pairs well with
Product specification
Why a trap primer?
Floor drain traps that do not connect to a water-supplied fixture tend to evaporate. Traps that are not periodically used, or are installed in overly dry areas, also lose their seal by simple evaporation. That loss lets known health hazards — hydrogen sulfide, methane, bacteria, viruses and mold — into the working space.
Trap primer flow controls
A trap primer is a flow control valve that adds water to a P-trap to maintain a water seal, preventing sewer gases from entering a building. There are two types: (1) pressure-drop trap primers and (2) electronic trap primers — available from J.R. Smith Fluid Controls.



Pro plumbing tip
Just like the P-trap, a trap primer is simple: it adds water to your plumbing trap. If liquid doesn't go down the drain often enough, the water seal at the bottom of the U-shaped trap eventually evaporates. With the seal gone, sewer gas can travel through the drain pipe into your processing rooms — a serious problem that can lead to a plumbing or health emergency, or even product recalls.
We can also build it to your specs. Call 888-244-3417 for pricing and availability.
More floor drains




Need a different size or outlet?
Outlets from 2" to 8", side outlets, locking and sealed covers — built to spec.
P-traps
Cleanouts
Drain baskets