Replace Drain Pipe in Mobile Prefab Toilet

Replacing the drain pipe in a mobile prefab toilet requires following standardized procedures. The specific steps and precautions are as follows:

I. Pre-construction Preparation

1. Tools and Materials

   • Select tools based on the pipe type: For PVC pipes, prepare wrenches, plumbing sealing tape, PVC-specific glue, and a saw (as backup); for cast iron pipes, prepare a saw, Teflon tape, and welding tools (if applicable).
   • Clear items from the toilet and remove sanitary fixtures (such as toilets and sinks) to create space for construction.

2. Shut Off Water Supply and Drainage

   • Turn off the main water supply valve to avoid getting wet during construction.
   • Drain residual water from the pipes: Open faucets or flush the toilet to ensure no water remains in the pipes.

II. Removal of Old Drain Pipe

1. Removal of PVC Pipe

   • Use a wrench to turn the interface nut counterclockwise to loosen it. If it is rusted, apply cooking oil or rust remover for lubrication. For stubborn cases, use a hot air gun to heat it before removal.
   • Clean old glue and rust from the interface to ensure a tight connection for the new pipe.

2. Removal of Cast Iron Pipe

   • Use a saw to cut the old pipe and clean rust from the interface until it reflects light.
   • If the pipe is hidden within a sunken box structure, pry open the covering and take photos to record the original slope to prevent backflow from the floor drain after installing the new pipe.

III. Installation of New Drain Pipe

1. Measurement and Positioning

   • Measure the position of the new pipe based on the location of sanitary fixtures (such as toilets and showerheads) to ensure smooth drainage and avoid blockages caused by misalignment.
   • Drill holes in the floor or wall (if necessary) to reserve space for pipe installation.

2. Connection and Fixing

   • PVC Pipe: Quickly connect using specialized glue and add waterproof glue and a sealing ring at the interface for double protection.
   • Cast Iron Pipe: Weld or use specialized connectors for fixing. Wrap metal interfaces with Teflon tape more than ten times clockwise to prevent leaks.
   • Tighten all interfaces by hand first, then use a wrench to turn them half a turn more to avoid breaking due to excessive force.

3. Ventilation and Odor Prevention

   • Install ventilation pipes according to national regulations to ensure smooth airflow.
   • Install odor-proof elbows at the drain openings (cost-effective and effective in reducing odors).

IV. Testing and Completion

1. Drainage Test

   • Pour a bucket of water and flush to observe if the drainage is smooth; or slowly pour bottled water into the pipes to check for leaks at the interfaces.
   • Observe with a small stream of water for 10-20 minutes and use tissue paper to wipe the interfaces to confirm no water seepage.

2. Sealing Holes and Restoration

   • After confirming no leaks, fill the drilled holes with cement or sealing materials to ensure they are flat and secure.
   • Restore sanitary fixtures (such as toilets and sinks) and clean the construction site.

V. Precautions

• Risk Avoidance: Improper operation may cause water leaks or damage to facilities. Non-professionals are advised to proceed with caution. For complex situations (such as replacement of the main sewage pipe), contact a professional.
• Compatibility: The material and specifications of the new pipe should match those of the original pipe to avoid affecting drainage performance.
• Slope Design: The drain opening should be higher than the drainage outlet, maintaining a slope of 1%-2% to prevent water accumulation.
• Preservation of Original Direction: Try to install the pipe following the original direction. Random changes may cause blockages.