The release valve in the handle of the Bellman steamer should only hiss once the Bellman reaches full pressure. Typically this would take 6-8 minutes when starting with boiling water, or 12-14 minutes when starting with cold water. In a correctly functioning Bellman, once it starts to hiss from the valve, it’s time to remove the steamer from the heat source.
If you find the release valve is hissing while it is heating and is not reaching full pressure. Contact us to arrange a return so we can inspect the unit, for repair or exchange.