GLOBAL GROUND SUPPORT
Regional Model 700 & 1200 Deicer
LESSON (7.) Hydraulic System
Purpose:
The purpose of this lesson is to provide the student with the knowledge and understanding of the deicer hydraulic system’s operation and components. Upon completion of this lesson, the student will have been provided with the knowledge to maintain, perform adjustments and troubleshoot this system.
Overview of System Operations:
The hydraulic system of the Regional 1200 deicer is comprised of two separate systems, all receiving fluid from the same reservoir, but independently filtered. These three systems control separate functions and for this reason, are easy to troubleshoot. The three systems are:
1. Boom functions
2. Deicing and anti-icing fluid pumps motors, heater blower motor and heater fuel pump motor.
The main hydraulic pump for the deicing and ant-icing motors, the heater blower motor, fuel pump motors and the boom pump are directly driven from the auxiliary engine. The main hydraulic pump is mounted directly to the auxiliary flywheel flex plate with the hydraulic boom pump mounted next to it. The main hydraulic pump, a Sundstrand Sauer Series 45 is a variable displacement, closed-loop pump. The hydraulic boom pump, a Sundstrand Sauer Series 5 is a fixed displacement, open-loop, gear-style pump.
The hydraulic system is a 65-gallon hydraulic tank mounted at the driver’s side rear corner of the deicer. The tank has purposely been mounted lower than the hydraulic pumps. This position, with shutoff valves, allows easy service and /or replacement of the hydraulic components without major loss of fluid. The tank is vented with a breather filter, which allows for safe, no-pressure when the supply cap is removed. On the side of the hydraulic is an external sight-level/temperature gauge. When checking the fluid level of the hydraulic tank, the level should be between the top and bottom mark to allow for fluid expansion. The fluid type is Mobil DTE 13. It is compatible with most other types of hydraulic oil. Refer with your fluid supplier for compatibility.
The deicer’s hydraulic system operates as follows: hydraulic fluid is drawn from the tank by the charge pump inside the main hydraulic pump, the pump then supplies the required GPM to operate the determined hydraulic systems. The max flow of the charge pump is 8 gpm.
NOTE:Even when working with hydraulic pumps, most adjustments are made using pressure setting pumps, which do not build pressure. Pressure is generated by the individual components used to make up the system such as the size of the motors, valves, cylinder, etc. The pump supplies fluid flow through the system, which is measured in gallons-per-minute (GPM). Increasing or decreasing the GPM flow rate controls system pressure. Increasing the flow will increase the system pressure while decreasing the flow will lower it. In a closed loop system with a variable displacement pump, the pump is adjusted to control the GPM. In an open-loop system, the boom pump speed controls the GPM.
Since both hydraulic systems are separate, the deicer is capable of performing multiple functions simultaneously. Example: the boom can be operated without affecting the operation of the deicing, anti-icing pumps or fluid heater. This allows the boom to be operated while spraying hot deicing fluid.
The deicing pump motor, anti-icing pump motor and fluid heater fuel pump motor and blower motor: This pump is a Sundstrand Suaer Series 45. Series 45 stands for 45 cc’s of oil per minute and is mounted directly to the auxiliary engine’s flywheel. This pump supplies the required GPM to operate the deicing and anti-icing pumps as well as the fluid heater blower and fuel pump motors.
Boom and Operator Basket: The boom and operator basket pump is a Sundstrand Sauer Series 5 (5 cc’s of oil per minute) and is mounted next to the Series 45 deicing/anti-icing pump. Fluid is pumped through the plumbing to the system components (cylinders, relief valve and control valve). The pump is mounted next to the main hydraulic pump, mounted on the auxiliary engine.
Major Components and Their Maintenance:
The deicer hydraulic pump is a Sundstrand Suaer Model Series 45. This pump is capable of working with 7,000 PSI of pressure; however, Global operates this pump at a system pressure of 2,200 PSI to 2,250 PSI. Global operates pumps at the lowest possible system pressure to increase pump life. There are two factors that shorten pump life: heat and contamination. Since unused pressure causes heat by lowering system pressure to the lowest possible system operating pressure, heat is reduced, which adds life to the hydraulic system.
Global filters the hydraulic fluid of each system separately. This greatly reduces contamination that could be generated by the motor reaching back to the pump because it is a closed-loop system. This also adds to increased pump and motor life. The Sundstrand Sauer pump has three different ports to obtain system pressure readings: the A-port, the B-port and the Charge-port. With the pump in neutral, all three of the pressure ports would read almost the same.
Most hydraulic pumps and motors have internal leakage. This internal leakage is used to lubricate and cool the pump or motor. The anti-icing hydraulic pump has a charge pump built into the pump. This charge pump makes up any leakage out of the case drains. This pressure is set at 270 PSI at 1,250 RPM of the auxiliary engine. This pressure also strokes the pump on when the electric solenoid is engaged. This pressure is adjustable and will be covered under “Adjustments” later in this lesson.
The main hydraulic pump is designed for use as a hydrostatic drive pump. The pump has two sides to it – A and B. Pump fluid from the A-port and a hydraulic motor turns in one direction.
Pump fluid from the B-port and the hydraulic motor turns in the opposite direction. Since this pump is not being used as a directional pump, only the A-port side of the pump is being stroked on.
NOTE:Both the A and B ports have identical adjustable multifunction valves used to adjust fluid flow / pressure. However the A-port multifunction valve is not used, giving the pump a built-in spare multifunction valve. A-port pressure is set at approximately 2,200 PSI to 2,500 PSI or 4,250 RPM on the deicing pump.
The main hydraulic pump provides hydraulic fluid flow to four hydraulic motors. The motors that are governed by this pump are as follows:
- Hydraulic Motor / Drives the Myers deicing pump / Requires no maintenance
- Hydraulic Motor / Drives the Hardi or Udor anti-icing pump / Requires no maintenance
- Hydraulic Motor / Drives the fluid heater fuel pump / Requires no maintenance
- Fluid Heater Blower Motor / Requires no maintenance
The adjustments of the speeds of these motors will be covered next in the “Adjustment and Flows Section” of this lesson.
System Pressures and Flow Rate Adjustments:
1. Sundstrand Main Hydraulic Pump
The system pressure for the main hydraulic system is 2,200 PSI to 2,250 PSI. To adjust this pressure, install a 5,000 PSI gauge at the gauge port, which is located at the fluid heater blower control valve at the passenger-side rear of the deicer body. Using the adjusting screw on the hydraulic pump ( the screw is at the top of the pump and faces the rear of the auxiliary engine), loosen the lock nut and with an Allen wrench, adjust the screw CW or CCW until a system pressure of 2,200 PSI to 2,250 PSI is seen on the gauge. Next, using a photo tachometer, check the speed of the deicing pump. It should be 4,250 RPMs. Adjust the main hydraulic pump pressure as previously mentioned until 4,250 RPMs is achieved. Tighten the lock nut and remove the gauge.
2.Boom System Relief Valve
The boom system relief valve pressure is set at 3,000 PSI. To adjust this valve, install a 5,000 PSI gauge at the gauge port coming from the filter at the end of the manual hydraulic control valve located on the driver-side center of the deicer body. Next, locate the relief valve at the opposite end of the control valve and remove the hex head cap. Loosen the jam nut and using an Allen wrench, adjust the cartridge CW or CCW until a 3,000 PSI appears on the gauge. Tighten the jam nut and reinstall the hex head cap, then remove the gauge.
3.Fluid Heater Fuel Pump
The fluid heater fuel pump speed is adjusted by a cartridge located in the green mono block mounted under the fluid heater. The cartridge can be found by locating the hydraulic line routed from the mono block to the fuel pump motor. With the auxiliary engine shut off, check to see if the coupling has a small piece of reflective tape on it. If none is found, clean off the pump/motor coupling and install a small piece of reflective tape on the coupler. This tape will serve as a target for the photo tachometer. Loosen the lock nut on the cartridge and start the auxiliary engine. Turn on the pump switch and energize the fuel pump by energizing the yellow wire on the fuel pump relay in the heater control box. This will energize the coil on the mono block. With the auxiliary engine at 2,150 RPM and both switches turned on, point the photo tachometer at the coupling and read the RPMs. Adjust the screw CCW or CW until 3,000 RPMs are achieved and a fuel pressure of 310 PSI is obtained. It may be necessary to change the RPM setting and fuel pump pressure until 310 psi of fuel pressure is at 3000 RPM on the pump. Tighten the lock nut – the fuel pump RPMs are now set.
NOTE:It may be necessary to change the RPM setting and/or fuel pressure setting to achieve the 310 fuel system pressure and the 3,000 RPM pump speed.
Troubleshooting:
- Low system hydraulic pressure for the deicing, anti-icing and heater systems. Possible reasons:
Mis-adjusted A-port multifunction valve
Plugged hydraulic filter
Bad Sundstrand Sauer pump
Bad deicing motor
Ball valve is turned off
- Low system pressure to the boom functions. Possible reasons:
Bad boom hydraulic pump
Mis-adjusted boom hydraulic relief valve
Plugged hydraulic filter
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