How to Renovate Heating in Prefabricated Slab Houses

When renovating heating in prefabricated slab houses, priority should be given to ensuring structural safety and compatibility. Traditional exposed radiators are a more reliable choice; if insisting on installing underfloor heating, strict evaluation of load-bearing capacity and floor height conditions is necessary, and reinforcement measures should be taken.

I. Comprehensive System Evaluation Before Renovation

1. Immediate Renovation Required for High-Risk Signals: If there is continuous water leakage or rusty water at the joints of radiators or valves, large-scale shedding of aluminum fins, or more than one-third of the radiators show the phenomenon of 'warm at the top and cold at the bottom' and flushing is ineffective, and if the expansion bolts of the brackets are loose or radial cracks appear on the wall, the system needs to be replaced immediately.
2. Upgrade Recommended Within 3 Years for Hidden Dangers: If the system has been in use for more than 12 years (the lifespan is shortened to about 10 years in areas with poor water quality), the indoor temperature remains below 18°C in winter after excluding building insulation issues, or a large amount of dark brown impurities are found when cleaning the filter and the pH value of the incoming hot water is less than 7, renovation planning is required.

II. Renovation Core: Strengthening Safety and Compatibility

1. Structural Safety: Choose lightweight copper-aluminum composite radiators (with water content per column ≤ 1.8 kg). When fixing the brackets, there should be at least 4 per group. Drill holes to avoid the joints of the prefabricated slabs (with a bearing capacity of approximately 0), and prioritize locating the main reinforcement bars of the floor slab.
2. Corrosion Protection Upgrade: Replace with copper pipes covered with a copper layer + aluminum fins with anodized radiators. Add magnetic descalers (to adsorb iron rust) and precision filters (to intercept impurities ≥ 40 microns) to the incoming pipes.
3. Hydraulic Adjustment: If the public riser is a rusted galvanized pipe, it should be replaced with a corrosion-resistant PB pipe simultaneously. Install automatic differential pressure balancing valves on the return pipes at the top and bottom floors to solve vertical temperature differences.

III. Suggestions for Heating Method Selection

1. Priority to Exposed Radiators: The load-bearing capacity of prefabricated slabs is limited. Underfloor heating may pose a risk of collapse due to excessive load, so exposed installation is safer.
2. Central Heating Renovation: After cutting off the main pipe, connect it to the underfloor heating pipes (load-bearing evaluation is required, generally not recommended), or directly lay dry underfloor heating (lightweight and does not compress the floor height, but the cost is high).
3. Wall-mounted Boiler Heating: Cut off the main pipe connecting the wall-mounted boiler to the radiators and connect the incoming and return water of the underfloor heating to the wall-mounted boiler.

IV. Special Considerations for Old House Renovation

1. Connection Form: Renovating a series-connected system to underfloor heating may affect the heating of the downstairs unit, so it is not recommended. For a parallel-connected system, pay attention to the impact of the underfloor heating coil + cement layer (3.5 cm - 5 cm thick) on the floor height.
2. Floor Height Limitation: When the standard floor height (2.8 meters) is insufficient, even if the load-bearing capacity meets the requirements, it is not recommended to lay traditional underfloor heating. Dry underfloor heating can be considered.

V. Emergency Safeguard Measures (When Renovation is Not Immediate)

1. Implement an annual 'intensive inspection': Before the heating season, inspect the welds of the radiators (ultrasonic flaw detection), the firmness of the brackets (tensile test ≥ 50 kg), and pipe corrosion (endoscope).
2. Install a water leakage alarm: Install a low-cost device on the back of the radiators to monitor leakage in real-time.