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Dayton 4UN78 screw-in check valve TPR MNPT connections vertical mount

Dayton

Dayton 4UN78 Check Valve TPR 1 1/4 in or 1 1/2 in MNPT

SKU CH-KZCG-TH62D MPN 4UN78

Inline check valve with TPR body for vertical mounting on 1-1/4 in or 1-1/2 in MNPT connections

  • TypeDrain Components
  • TPR body resists corrosion for long service life
  • Single flow design prevents backflow in drainage systems
  • Inline mechanism allows straight-through installation
  • Vertical mounting orientation suits standard drain layouts
  • MNPT connections fit 1-1/4 or 1-1/2 inch pipe threads

Purpose and Fit

The Dayton 4UN78 is a screw-in check valve built for general-purpose drainage lines that use 1-1/4 inch or 1-1/2 inch male NPT threads. It suits installers who need a simple inline device to stop reverse flow in vertical pipe runs.

Build and Connections

The valve body is moulded from TPR and uses a single-flow inline mechanism with MNPT threads on both ends, so it threads directly into existing fittings without adapters. Vertical mounting orientation means the valve sits upright in the line, keeping the sealing action gravity-assisted and the joint accessible for inspection.

Compatibility Check

Confirm that your drain piping uses the stated thread sizes and that the system operates within the valve's non-rated steam-pressure limit. Verify local code acceptance for TPR-bodied check valves before installation.

Highlights

  • TPR body resists corrosion for long service life
  • Single flow design prevents backflow in drainage systems
  • Inline mechanism allows straight-through installation
  • Vertical mounting orientation suits standard drain layouts
  • MNPT connections fit 1-1/4 or 1-1/2 inch pipe threads

Specifications

TypeDrain Components
BrandDayton
Model4UN78

Questions about this item

What does the MNPT x MNPT connection mean for pipe compatibility?

Both ends use male National Pipe Taper threads so the valve screws directly into female-threaded fittings of either 1 1/4 in or 1 1/2 in nominal size.

What clearance is needed to install this inline check valve vertically?

The body must be mounted vertically; allow enough straight pipe run above and below for the valve length plus wrench access on the hex flats.

How do you avoid installing the valve backwards?

Follow the flow arrow cast on the TPR body — water must enter the inlet side marked by the arrow; reversing it blocks flow and defeats the check function.

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