The lack of heat on the surface of the underfloor heating system can generally be attributed to six aspects: air, blockage, valves, pressure, design, and usage. The most common reason is "air blockage" in the pipes-the supply pipe of the manifold is hot while the return pipe is cold. In this case, simply bleed the air from each circuit one by one until a stable supply of hot water is obtained. Secondly, valves may not be fully open, or filters may be clogged: check whether the inlet shut-off valve, the main valve of the manifold, and the valves of each branch circuit are in the open position with the handle parallel to the pipe, and clean the filter screen before the manifold regularly, as impurities are often the culprit for poor water flow. Long-term uncleaned underfloor heating pipes will accumulate scale, which will seriously affect heat dissipation efficiency-even if the scale is only 1 mm thick, the water temperature may drop by 6-8°C. It is recommended to have the pipes thoroughly cleaned by professionals every 2-5 years. If the entire community or building is generally not heating up, it may be due to insufficient pressure at the heating source or a low initial temperature, requiring confirmation from the heating company. Design and construction defects can also create hidden problems. For example, excessively large pipe spacing, uneven loop lengths, and sharp bends or flattening of pipes can all lead to increased circulation resistance or uneven heat dissipation. Furthermore, large areas of carpet or clutter on the floor can hinder heat dissipation, lowering the room temperature by 3-5°C. Wooden floors (especially solid wood) have much lower thermal conductivity than ceramic tiles, and a neighbor's unauthorized installation of a circulation pump can disrupt the system's hydraulic balance, causing heat to be "stolen" from your home. When troubleshooting, it's recommended to first inquire with neighbors to rule out external network problems, then check the valves and filters, and try bleeding air. If the problem persists or the underfloor heating system hasn't been cleaned for years, contact a professional repair company. In short, most underfloor heating issues are due to poor circulation or obstructed heat dissipation. By systematically checking the above aspects, most problems can be resolved.