Gas-fired heater has a gas/air mixture receives a supply of fresh air via a regulator delivering a regulated volume of fresh air to burner

摘要

A gas-fired central heating unit has a burner and a heat exchanger in which hot burned exhaust gases pass through an inner pipe with a surrounding outer pipe. The gases combine with air in a mixer. The burner receives a mixture of unburned gas and fresh air via a non-regulated blower and mixer. The mixer unit (17) receives a supply of fresh air (a) esp. via a regulator (16) delivering a regulated volume (d) of fresh air (a).