Bathtub automatic siphon McAlpine MP31SSF-WHBR, white body with brass knob

The McAlpine MP31SSF-WHBR automatic bathtub siphon is a concealed waste control device for bathtubs, featuring a white body and a brass finish knob. It provides an automatic opening and closing function for the waste outlet, allowing controlled water release and reliable sealing when closed. Designed for standard bathtub installations, the siphon integrates with hidden drainage systems to maintain a clean visible surface and simplify bath use.

Advantages

The siphon offers automatic pop-up waste operation that can be controlled via the brass knob on the visible surface, combining aesthetic appearance with practical functionality. Its concealed design reduces exposed components around the bath rim, and the white body matches common bathtub interiors. The mechanism is intended to give a watertight seal when closed and straightforward water drainage when opened.

Suitable for

• Standard built-in bathtubs with concealed waste piping
• Renovations where a neat, low-profile waste control is desired
• Bathrooms requiring a white-finished waste with a brass control knob for matching fittings

When it may not be suitable

This automatic siphon is intended for standard bathtub drain configurations; it may not fit non-standard or custom waste systems without compatible inlet/outlet dimensions. It may also be unsuitable where an exposed or external overflow system is specified or where specific non-standard materials or finishes are required.

Key specifications

• Function: automatic opening and closing pop-up waste
• Body finish: white
• Control knob finish: brass
• Installation type: concealed bathtub waste
• Operation: manual knob actuation for release and seal

How to use

Install the siphon in the bathtub drain according to manufacturer guidance and ensure the concealed waste piping aligns with the unit. Operate the waste by turning or pressing the brass knob as intended to switch between sealed and open states; verify the seal by filling the tub partially and checking for leaks. Routine operation involves normal manual actuation of the control knob to retain or release bath water.

What to consider before purchase

• Confirm compatibility with your bathtub's waste connection and concealed piping layout
• Ensure the white body and brass knob match other bathroom fittings
• Check required installation clearances and access for maintenance

Usage recommendations

For reliable performance, inspect the sealing surfaces during installation, tighten fittings to appropriate torque without over-tightening, and test the pop-up operation before finalising the bath trim. If uncertain about fit or plumbing connections, consult a qualified plumber to ensure correct installation and leak-free operation.