

Product Features:
Walvoil VDA 3/8" BSP Unloader Valve, 25 L/min, 100-250 Bar, Aluminium
Product: Walvoil VDA 38 3/8" BSP Unloader Valve, 25 L/min, Aluminium, 100-250 Bar
The Walvoil VDA 38 is a single acting hydraulic unloader valve with a built-in check valve, automatically operated by an internal pressure pilot.
This VDA 38/TR.S.VRR configuration features an aluminium body, G3/8 standard threaded connections, 25 L/min nominal flow and a 100-250 bar pressure setting range. Walvoil product code: 1210021101.
Main Features
- Adjustable pressure setting range from 100-250 bar (1450-3600 psi)
- 25 L/min (6.6 US gpm) nominal flow capacity
- G3/8 standard threaded hydraulic connections
- Single acting unloader valve with built-in check valve
- Lightweight aluminium valve body
Technical Data
| Specification | Details |
|---|---|
| Manufacturer | Walvoil |
| Valve Series | VDA 38 |
| Full Type | VDA 38/TR.S.VRR |
| Walvoil Code | 1210021101 |
| Valve Type | Hydraulic Unloader Valve |
| Operation | Automatically Operated by Internal Pressure Pilot |
| Configuration | Single Acting with Built-In Check |
| Port Size | G3/8 Standard Thread |
| Body Material | Aluminium |
| Pressure Setting Range | 100-250 bar (1450-3600 psi) |
| Standard Setting | 200 bar at 5 L/min (2900 psi at 1.32 US gpm) |
| Standard Differential Pressure | 15% |
| Nominal Flow | 25 L/min (6.6 US gpm) |
| Recommended Fluid | Mineral Based Oil |
| Oil Viscosity | 10-200 cSt |
| Maximum Contamination Level | 18/16/13 ISO 4406 |
| Fluid Temperature | -20°C to +80°C with NBR seals |
| Environmental Working Temperature | -40°C to +100°C |
| Approx. Weight | 2.15 kg (4.73 lb) |
Walvoil VDA Model Variations
The Walvoil VDA range is available with different port sizes, aluminium or steel bodies and optional drain port configurations. The current 1210021101 model is highlighted below.
| Walvoil Code | Type | Port Size | Body | Drain Port | Setting Range |
|---|---|---|---|---|---|
| 1210021101 | VDA 38/TR.S.VRR | G3/8 | Aluminium | No | 100-250 bar |
| 1210021113 | VDA 38/DR/TR.S.VRR | G3/8 | Aluminium | Yes | 100-250 bar |
| 1210022101 | VDA 38/TR.S.VRR/ac | G3/8 | Steel | No | 100-250 bar |
| 1210031101 | VDA 12/TR.S.VRR | G1/2 | Aluminium | No | 100-250 bar |
| 1210031104 | VDA 12/DR/TR.S.VRR | G1/2 | Aluminium | Yes | 100-250 bar |
| 1210032101 | VDA 12/TR.S.VRR/ac | G1/2 | Steel | No | 100-250 bar |
| 1210041101 | VDA 34/TR.S.VRR | G3/4 | Aluminium | No | 100-250 bar |
| 1210041108 | VDA 34/DR/TR.S.VRR | G3/4 | Aluminium | Yes | 100-250 bar |
| 1210042100 | VDA 34/TR.S.VRR/ac | G3/4 | Steel | No | 100-250 bar |
How the Walvoil VDA Unloader Valve Works
The Walvoil VDA is an unloader valve automatically operated by an internal pressure pilot. The valve is designed to unload the hydraulic circuit when the predetermined pressure condition is reached.
The single acting configuration incorporates a built-in check valve, providing a compact solution for hydraulic systems requiring automatic unloading and pressure management.
Key Benefits
- Automatic operation through an internal pressure pilot
- Built-in check valve reduces the need for separate circuit components
- Adjustable 100-250 bar pressure setting range
- Multiple G3/8, G1/2 and G3/4 configurations available
- Aluminium, steel and drain-port variants available within the VDA range
Pressure specification note: Walvoil specifies a 100-250 bar pressure setting range for product code 1210021101.
Always confirm the required port size, body material, drain configuration and Walvoil product code against your hydraulic system before ordering.
Choosing the Correct Walvoil VDA Valve
Choose the required VDA model according to the hydraulic port size, body material and whether an external drain port is required.
If replacing an existing valve, matching the complete Walvoil type and product code is recommended wherever possible.
Contact Us for product identification, availability and delivery information.
General delivery information
Thank you for visiting and shopping at www.flowfitonline.com. Below are the terms and conditions for the Shipping Policy for Harrier Fluid Power Ltd T/A Flowfit.
Orders are processed and shipped during standard working hours (08:30–17:00 BST), Monday to Friday (excluding Bank Holidays). All orders placed before 4pm Monday to Thursday and 3pm on Friday are normally processed and despatched on the same business day, subject to stock availability.
Build and assembly orders may require additional processing time. This includes, but is not limited to, hydraulic power units, gearbox and pump assemblies, hydraulic hose assemblies, and motor/engine pump sets. Due to current demand, these types of orders are currently experiencing an estimated additional 2–3 working days before despatch.
During periods of particularly high order volumes, delivery times may be extended further. Please allow additional time in transit for delivery once your order has been despatched.
If your order is extremely urgent and next-day delivery is critical, please contact our Sales Team before placing your order. We will do our best to accommodate your requirements and advise whether we can meet your requested delivery date.
If there will be a significant delay to your order, we will contact you via email or telephone.
United Kingdom delivery rates & estimates
| Service | Price | Terms |
|---|---|---|
| FREE Delivery | FREE | Free UK delivery is available for orders over £99.99+ VAT. Delivered in 1 -2 working days. |
| Express Delivery | £9.99 + VAT | UK Mainland delivery for orders under £99.99 + VAT. Delivered in 1 -2 working days. |
| Express 9am | £42.95 + VAT | Delivered by 9am next working day. |
| Express 12pm | £20.95 + VAT | Delivered by 12pm next working day. |
| Channel Islands | ||
| Standard Delivery | £20.95 + VAT | Delivery in 2–3 working days. |
| UK Highlands & Isles | ||
| Order value below £99.99 + VAT | £31.95 + VAT | Delivery in 2–3 working days. |
| Order value over £99.99 + VAT | £28.95 + VAT | Delivery in 2–3 working days. |
* Overnight delivery is only available for certain delivery addresses within the United Kingdom. Please contact us beforehand to confirm eligibility.
Email sales@flowfitonline.com or call 01584 876 033.
Collection: Customers are welcome to arrange collection using a courier of their choosing, or collect in person from our depot in Ludlow, Shropshire. Please advise us in advance so we can ensure your order is complete before collection.
International delivery rates & estimates
Shipping charges depend on weight and destination country and are calculated and displayed at checkout. Orders for delivery within the EU typically arrive on a 2–5 day service (depending on the destination). Shipments outside the EU typically arrive on a 3–7 day service (depending on the destination).
Please contact our Sales team for accurate delivery times. If your parcel has not arrived within the expected timeframe, please get in touch. Please ensure the shipping address entered at checkout is correct; we are not responsible for incorrect or undeliverable addresses.
Customs, duties and taxes
Import duties, taxes, and brokerage fees are not included in the product price or shipping and handling costs. These charges are the buyer’s responsibility. You may check with your country’s customs office to determine any additional costs.
By placing an international order (shipping outside the United Kingdom), the buyer is responsible for complying with their country’s laws, regulations, and restrictions. If a product is seized and destroyed by customs, we will not be responsible for losses, products, or shipping refunds.
Shipment confirmation & order tracking
You will receive a Shipment Confirmation email once your order has shipped, containing your tracking number(s). Tracking will be active within 24 hours.
Working closely with top carrier experts
We use some of the top carrier companies in the world, although you can also use your own carrier to collect your order. All deliveries require a signature on delivery. Below are our main carrier companies.

Damages
Harrier Fluid Power Ltd T/A Flowfit is not liable for products damaged or lost during shipping. If you receive your order damaged, please contact us to file a claim. Please save all packaging materials and damaged goods before filing a claim.
Returns policy
Our Return & Refund Policy provides detailed information about options and procedures for returning your order.
