Heating system flushing

When flushing is needed

• Radiator is hot at the top, cold at the bottom
• Some radiators don't heat up at all even though the valve is open
• Gurgling or knocking noise is heard in the system
• Heating bills have risen, but rooms are cooler than before
• The system hasn't been cleaned in over 10–15 years

How flushing is done

We connect a flushing device to the system and pass a water-air mixture through the loops, dissolving and carrying out accumulated sediment. For a hard sludge layer we use chemical flushing, which dissolves scale and corrosion products without dismantling the pipes or radiators.

After flushing we fill the system, vent every radiator, and check that heat reaches every room evenly. In an apartment building flush, we go through all the risers, not just a single apartment.

How flushing differs from maintenance and repair

Heating system maintenance is a lighter, scheduled inspection (pressure, venting, valves). Heating system repair solves a specific fault, such as a leak. Flushing, however, is a thorough internal cleaning that removes sediment built up over the years — often what makes the other work effective.

Who it suits

• Apartments where radiators no longer heat their full surface
• Apartment buildings and housing associations before the heating season
• Houses where an old system has gone untouched for years
• Commercial buildings where heat is uneven between floors

What affects the scope of flushing

Scope is determined by the number of radiators and loops, the system layout (single-pipe or two-pipe), the amount of sediment, and whether a single apartment, a whole riser, or the entire building is being flushed. In an old apartment building it may make sense to combine flushing with cleaning the heat substation filters, so sediment doesn't return to the system right away.