3 Pass Vacuum Hot Water Boiler

ZBG manufactured ZWNS vacuum hot water boiler adopts three pass structure, with wetback reversal chamber structure, to ensure highest thermal efficiency. Each set of tubes that hot combustion flue gas travels through before making a turn within the boiler, is considered a "pass." Hot water in boiler chamber will flow three times in horizontal tubes which provides more opportunities for hot gasses to transfer heat to the water in a boiler. However, boiler efficiency is highly affected by tube design, and not simply the number of passes. 3-pass boiler with more heat transfer time to deliver the same or higher efficiency rating.
ZWNS 3-pass boiler design consists of three sets of horizontal tubes, with the stack outlet located on the rear of the hot water boiler. A downdraft design keeps the cooler water from having an effect on the hot surfaces within the boiler.
High sustained efficiency without the danger of reaching the due-point under low load conditions. The formation of condensate, in the form of weak sulphurous or sulphuric acid, has been known to occur on units with more than three passes when operating under these conditions, resulting in quick deterioration of the last pass tubes, and resulting in costly repairs.
Three pass design vacuum hot water boiler, zero explosion, runs in negative pressure, supply hot water to hotels, swimming pools, heating companies, etc. For further information about our hot water boiler, please contact with our consumer service or leave us a message.