Varmebypass

Varmebypass refers to a bypass loop installed in a heating system, typically a hydronic or hot water system. The primary function of a varmebypass is to regulate the flow of water within the system and to protect certain components, most notably the boiler.

In a boiler system, especially those with cast iron heat exchangers, rapid temperature fluctuations can cause thermal shock. This can occur when a boiler fires up, heating the water to its set point, and then quickly shuts off due to the thermostat being satisfied. If the system is designed for constant flow through the boiler, this rapid on-off cycling can lead to condensation within the boiler, which can be corrosive and damage the heat exchanger over time. The varmebypass helps to mitigate this by allowing a portion of the heated water to recirculate back to the boiler's return line, even when there is little or no demand from the heating circuit (radiators or baseboard heaters). This keeps the boiler water temperature more stable and above the dew point, preventing condensation.

Additionally, varmebypass can be used to control the flow rate to specific zones or heating devices. By adjusting the size of the bypass line or incorporating a balancing valve, installers can fine-tune the distribution of hot water throughout the building, ensuring that all areas receive adequate heating. This can be particularly useful in systems where the main pump has a fixed speed and may generate too much flow for certain sections of the heating circuit. The bypass absorbs excess flow, preventing components like thermostatic radiator valves from being overwhelmed and operating inefficiently. In essence, a varmebypass acts as a control mechanism, safeguarding equipment and optimizing heat distribution.