# 20399145 Reducing Valve | Genuine Volvo Penta Part

🔧 Product Description

  

Genuine Volvo Penta Pneumatic Control Pressure Reducing Valve - Part Number: 20399145

  

Genuine Volvo Penta reducing valve used in the compressed-air control circuit on DH10A and THD102 installations. It regulates supply pressure for the pneumatic shutter or exhaust-brake control system.

  

⚙️ Key Features

  

• Pneumatic pressure-reducing and regulating valve

• Used in the engine air-control or exhaust-brake shutter circuit

• Confirmed on DH10A and THD102 engine installations

• Maintains controlled downstream pressure

• Requires clean dry air and leak-free hose connections

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 20399145 - current Volvo Penta reducing-valve reference

  

OEM / Related Numbers:

  

• 8151868 - related shutter housing

• 8158342 - related solenoid valve

• 948525 - related hose assembly

• 479690 - related leak-off line

  

Aftermarket / Verified Equivalents:

  

• None confirmed

  

🚤 Compatibility

  

Commonly used on:

  

• Volvo Penta pneumatic shutter and exhaust-brake control systems

  

Typically suits:

  

• Engine / equipment models:

• DH10A

• THD102KB

• THD102KD

• THD102K-KB

  

• Engine Type: Volvo Penta 10-litre diesel

• Year / Serial Range: Pneumatic-system layout and engine serial-number dependent

  

🔌 Function

  

Reduces compressor or reservoir pressure to the controlled pressure required by the downstream shutter or actuator circuit.

  

Common signs of failure:

  

• Downstream pressure too high or too low

• Exhaust-brake or shutter not operating correctly

• Continuous hissing or air leakage

• Valve sticking or slow response

• Pneumatic actuator cycling erratically

  

📦 Condition

  

• Genuine Volvo Penta part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 202.36 AUD
- **Vendor:** Volvo Penta
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 202.36 AUD | In stock |

## Images

- 20399145 Reducing Valve | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/20399145-reducing-valve-genuine-volvo-penta)
> Updated: 2026-07-29