3931A Shop Vacuum Review
The Bosch 3931A shop vacuum features a tool-triggered start mechanism and a 13-gallon capacity
The Bosch 3931A allows you to dial down the power demand of the vacuum motor, thus allocating more amps to the tool you’re using. In addition, it has a method of circuit protection called the Power Broker System. To use this feature, subtract the portable tool’s amp rating from the supplying circuit. Turn the Power Broker dial to the difference, and the vacuum modifies its draw, allowing you to work within the capacity of the circuit.
The vacuum’s tubular-metal rear handles and large rear wheels enable it to be maneuvered much like a hand truck, although its bulk and low ground clearance limit its portability. It can be used without a bag, but a bag is recommended because upending the canister is awkward. Its filter can be upgraded to a HEPA filter.
The vacuum has an automatic feature called Pulse Clean. When the portable tool is shut off, the vacuum remains on for seven seconds to clear the hose of dust. The machine then determines if the filters are dirty and, if needed, sends an electromagnetic pulse that causes the filter to shake, letting debris fall into the canister.
The Bosch 3931A was the only model tested that has a drain plug, ensuring complete release of wet contents.