PTO Driven Pump System utilizes the truck transmission via a PTO and drive shaft to power the water pump. A normal PTO outlet is normally only recommended to produce 30HP output therefore the pump size must fall below 30HP, this would be a 4 x 3 (4" suction inlet and 3" discharge outlet) 900 G.P.M. pump. This type of drive is usually the least expensive way to drive a pump but in most susceptible to operator damage due to all the external moving parts and leaving the pump engaged while transporting.

Transmission PTO hydraulic pump system. This group should be geared to a 30 HP pumping system. The hydraulic pump is directly mounted to the transmission PTO with
no exposed moving parts. This type of pump drive is the most common, and is the least expensive of all the hydraulic driven systems.

Hydraulic driven pump systems, there are two types of these systems, 1st is a transmission driven PTO Hydraulic pump group, and 2nd is a front of engine direct drive Hydraulic pump group. In each of these types of hydraulic groups there are three different types of pumping systems.

Front of engine direct drive hydraulic system. In this system the hydraulic pump is driven off the engine damper pulley via a drive shaft this drive shaft can either directly connected to the hydraulic pump, thus requiring the pump to self contained with an internal spool valve (most common) or connected through an electric clutch thus also providing the ability to turn the system off.

VVV: Variable drive - Variable flow - Variable pressure, standard hydraulic driven system: Since the hydraulic pump connected to the engine or the transmission the flow output is directly related to the engine speed (RPM), as the speed increases or decreases the hydraulic pump flow output increases and decreases which directly affects the water pump speed. This is the most common system and is the least expensive of the hydraulic drives.

VCV: Variable drive - Constant flow - Variable pressure, the hydraulic pump is connected to the engine or the transmission however the hydraulic pump flow is over sized to the motor flow acceptance. The hydraulic flow stream is diverted through a priority valve that provides a constant gallonage set flow to the hydraulic motor within and gives range of the engine RPM. The excess flow is diverted back the hydraulic reservoir. When the engine RPM is low the priority flow valves send all the flow to the hydraulic motor. Advantages of this system are regardless of the truck speed (within set range) the water flow will remain constant to each spray. Disadvantages are that heat can build up in the hydraulic system. It's recommended to run the hydraulic lines through the water tank, thus providing its own heat exchanger. Larger pumps may be used with this system 4 x 4 - 1100 G.P.M., and 6 x 5 - 1500 G.P.M. along with suction loading system pumps.

VCC: Variable drive - Constant flow - Constant pressure - Is used to describe a system that is driven by a variable displacement, pressure compensated, hydraulic pump that regulated the output flow by using the output hydraulic line pressure. Since hydraulic pressure and flow are related to a down stream orifice can be created to allow only a set hydraulic flow at a set hydraulic pressure if the pressure falls below the regulated minimum, a signal is sent back to the hydraulic pump enlarging the stroking action to provide more hydraulic flow. As the flow increased or decreases only the prescribed hydraulic flow can pass through the set orifice at the set pressure. Advantages are, regardless of the truck speed the water pump is always constant thus providing constant flow and pressure to the spray heads. Also with this type of system flow meters can easily be installed into each spray head to regulate exact flow and aid in chemical injection systems. Disadvantages are the expense, high heat build up, and working with 3000 PSI hydraulic pressures. It's recommended to run the hydraulic lines through the water tank, thus providing its own heat exchanger. Larger pumps may be used with this system 4 x 4 - 1100 G.P.M., and 6 x 5 - 1500 G.P.M. along with suction loading system pumps.