Most plate heat exchanger manufacturers have three different ways to seal the plates together: gaskets, brazing, or welding. The latter two options take away the modularity, but they add stability and reliability. That low-maintenance factor is one reason brazed plate heat exchangers are preferred in the HVAC industry, where small units are installed in combi boilers or similar heating equipment. However, gaskets are preferred in most industrial processes to allow for easier maintenance and possible expansion.