Water Pump System
The Gran Maestria is equipped with a rotary vane pump. This pump is made of two pieces - a brass rotary vane pump head and an electric motor to turn the pump. The brass pump head is attached to the electric motor by a clamp or bolted flange. The placement of this pump varies by model and age of machine, so in some cases, the pump assembly will be external. Most current machines, however, have an internal pump assembly, and in some cases, the electric motor will be water-cooled. This type of pump created the most reliable form of group head pressure.
Pump Servicing
- Rotary vane pumps are adjustable. It's necessary to adjust the pump to create the desired pressure at the group head. Adjustment is made by way of a screw found on the brass portion of the assembly. A clockwise adjustment will increase pressure, while a counterclockwise adjustment will decrease pressure.
- Inlet pressure is also accounted for in this adjustment, so when installing our machine, make sure the inlet pressure is less than two bars. If inlet pressure is higher than this, you should install a Watts-type water regulator to decrease it.
Pump Failure
- When a rotary vane pump starts to fail, one telltale sign will be an overly active pressure gauge. When you are pulling a shot, watch the gauge; if it is dancing around, there's a good chance the pump needs to be replaced. Other signs that your pump may be bad are low pressure at the group head and a lack of adjustability.
- The reason most rotary pumps fail is a lack of water. Even if the pump runs dry for only a moment, it may be damaging. You should never let an espresso machine with a rotary vane pump draw water from a water tank or a non-pressurized water source, because it will only increase the chance of damaging the pump. Rotary vane pumps require a pressurized water source to work properly.
- If you need to use your machine where a pressurized source of water is not available - such as in a catering situation or at a trade show - be certain to use an external diaphragm pump. These are manufactured by a number of companies, and they ensure you will be providing the correct inlet pressure to your machine.
- If you have a water filtration system in place, make sure it's in good working order, as the water pressure can dissipate over time. Filtration systems can easily become clogged with the debris you are trying to remove from the water. If a filter reduces water flow, this can also cause potential damage to the water pump.
- REPLACE WITH ROTARY VANE PUMP MOTOR - STANDARD 110V MOTOR
