 | |
| Illustration 1 | g00942505 |
(1) Thermal bypass valve (2) Return manifold (3) Output to the oil cooler (4) Output to the hydraulic tank | |
 | |
| Illustration 2 | g00931777 |
Schematic of the return manifold (1) Thermal bypass valve (3) Flow to hydraulic oil cooler (4) Flow to hydraulic tank (5) Case drain line (1 of 5) | |
Thermal bypass valve (1) is integral to return manifold (2). The return valve directs the case drain oil and the return oil to either the tank or the hydraulic oil cooler.
Components of the Thermal Bypass and Return Manifold
Return Manifold
The return manifold is located on the left side of the compactor under the operator platform.
Case drain lines from the following components are connected to the return manifold:
- Axle propel pump
- Vibratory pump
- Drum motor
- Vibratory motor
- Axle motor
Thermal Bypass Valve
 | |
| Illustration 3 | g00931805 |
Thermal Bypass Valve (6) Cap (7) Piston (8) Actuator spring (9) Pressure relief spring (10) Valve | |
The thermal bypass valve is a temperature transducer with a bypass spool and a relief valve. The temperature transducer controls the position of the bypass spool. The bypass spool controls the volume of oil that flows through the oil cooler. The relief valve limits the maximum pressure in the oil cooler to 350 kPa (51 psi).
When the hydraulic oil temperature is below 65°C (149°F) the thermal bypass valve directs charge flow to the tank.
When the hydraulic oil temperature reaches 65°C (149°F), oil is directed through the oil cooler. As the temperature of the oil rises, the bypass valve closes farther. Total oil flow to the cooler is approximately 50 L/min (13 US gpm) when the temperature of the oil reaches 71°C (160°F).