A theoretical problem with Savery's device stemmed from the fact that a vacuum could only raise water to a maximum height of about ; to this could be added another , or so, raised by steam pressure. This was insufficient to pump water out of a mine. In Savery's pamphlet, he suggests setting the boiler and containers on a ledge in the mineshaft and even a series of two or more pumps for deeper levels. Obviously these were inconvenient solutions and some sort of mechanical pump working at surface level – one that lifted the water directly instead of "sucking" it up – was desirable. Such pumps were common already, powered by horses, but required a vertical reciprocating drive that Savery's system did not provide. The more practical problem concerned having a boiler operating under pressure, as demonstrated when the boiler of an engine at Wednesbury exploded, perhaps in 1705.
A theoretical problem with Savery's device stemmed from the fact that a vacuum could only raise water to a maximum height of about ; to this could be added another , or so raised by steam pressure. This was insufficient to pump water out of a mine. In Savery's pamphlet, he suggests setting the boiler and containers on a ledge in the mineshaft and even a series of two or more pumps for deeper levels. Obviously these were inconvenient solutions and some sort of mechanical pump working at surface level – one that lifted the water directly instead of "sucking" it up – was desirable. Such pumps were common already, powered by horses, but required a vertical reciprocating drive that Savery's system did not provide The more practical problem concerned having a boiler operating under pressure, as demonstrated when the boiler of an engine at Wednesbury exploded perhaps in 1705.