Is the Hydraulic spool valve, operated by hand lever, type YFM35 compatible with hydraulic fluids other than mineral oil (e.g., biodegradable fluids)?

Hydraulic spool valve, operated by hand lever, type YFM35 Format: The valve described uses NBR (nitrile) seals and is specified for operating temperatures from -20Â°C to +80Â°C. Compatibility with fluids other than mineral oil (e.g., biodegradable fluids) depends primarily on seal and material compatibility as well as fluid viscosity and additive chemistry. - NBR seals: NBR has good resistance to standard mineral oils but limited resistance to many biodegradable fluids, especially those based on esters (synthetic esters) or glycol/water mixtures (HFC/HFDU types), which can cause swelling, hardening or accelerated aging. Some biodegradable hydraulic fluids (certain high-quality synthetic esters formulated to be NBR-compatible) may be acceptable, but many are not. - Materials: Cast iron body and hardened steel spools are generally compatible with most hydraulic fluids; corrosion inhibitors in some fluids should be checked. - Operating limits: Ensure the fluidâs viscosity at operating temperatures keeps pressures and flow within spec (max working pressure 315 bar, return 25 bar). Some biodegradable fluids have different viscosity/film strength and may require pressure/temperature consideration. Recommendation: Do not assume compatibility. Verify the exact biodegradable fluidâs manufacturer data for compatibility with NBR and steel/cast iron, or replace seals with materials rated for the chosen fluid (e.g., FKM/Viton, HNBR, or EPDM depending on fluid chemistry). Conduct supplier confirmation or bench testing before use in service.

Does the Hydraulic spool valve, operated by hand lever, type YFM35 require special maintenance intervals due to its centering springs and manual lever operation?

Hydraulic spool valve, operated by hand lever, type YFM35 Format does not require special or more frequent maintenance solely because it has centering springs and manual lever operation. Standard maintenance focuses on: keeping hydraulic fluid clean and at correct specification (NBR-compatible), inspecting seals and sliders for wear, checking for leaks, ensuring the centering springs and lever move freely and are not damaged or corroded, and verifying the built-in type C safety valve setting (140 bar) and overall system pressures (max 315 bar, return max 25 bar). Also monitor for unusual play or sticking at low/high temperatures (-20Â°C to +80Â°C). Follow manufacturerâs general maintenance intervals for hydraulic components and adjust frequency if operating in severe conditions.

How should the Hydraulic spool valve, operated by hand lever, type YFM35 be mounted to ensure correct centering spring function?

To ensure correct centering spring function when mounting the Hydraulic spool valve, operated by hand lever, type YFM35, follow these guidelines: 1. Mount the valve horizontally with the lever accessible and the spool axis level. Incorrect tilt can cause unequal spring preload and impede return to neutral. 2. Secure the valve body firmly to a flat, rigid surface using appropriate bolts through the mounting holes to prevent movement or vibration that would alter spring centering. 3. Fit hydraulic lines according to the manufacturerâs port labeling and recommended torque values; avoid external loads or hoses that produce side forces on the valve body or spool. 4. Ensure the lever travel is unobstructed and aligned with the spool axis so the lever returns freely to center; do not bend or tension the lever linkage. 5. Check that centering springs are installed and retained correctly inside the valve (factory-fitted type YFM35 centering springs). If springs have been removed for service, reassemble per original orientation and seating to guarantee equal spring preload on both ends of the spool. 6. Maintain operating conditions within specified limits (max working pressure 315 bar, return pressure â¤25 bar, temperature â20Â°C to +80Â°C). Excessive pressure or temperature can affect spring performance. 7. After mounting, cycle the lever several times and verify the spool reliably returns to neutral under spring action without hydraulic assistance; if not, inspect for misalignment, foreign debris, damaged springs, or incorrect assembly. Following these steps ensures the centering springs in the Hydraulic spool valve, operated by hand lever, type YFM35 function correctly and provide reliable neutral positioning.

Directional valve hydraulic spool, pilot-operated hand lever, type YFM35

All products, Directional control valves/

Additional information

Maximum operating temperature [°C]	80
Minimum operating temperature [°C]	-20

A monoblock Directional valve spool YFM35 pilot-operated hand lever of centering springs. Intended for hydraulic systems of cranes, lifts, construction and agricultural machinery, etc.. As standard, equipped with a type C safety valve (set to 140 bar) and type 1 spools. Material: cast iron (body), steel hardened (spools). Sealing: NBR. Maximum working pressure: 315 bar. Maximum return pressure: 25 bar. Operating temperature: from -20°C to +80°C.

List of product variants

Article number	Product variant name	DN	BAR	Availability	Actions
TL-YFM35-1-C-1	Hydraulic directional valve YFM35, 1-section with a valve overflow	-	315	In stock	Enquiry
TL-YFM35-2-C-11	Hydraulic directional valve YFM35, 2-section with a valve overflow	-	315	In stock	Enquiry
TL-YFM35-3-C-111	Hydraulic directional valve YFM35, 3-section with a valve overflow	-	315	In stock	Enquiry
TL-YFM35-4-C-1111	Hydraulic directional valve YFM35, 4-section with a valve overflow	-	315	In stock	Enquiry
TL-YFM35-5-C-11111	Hydraulic directional valve YFM35, 5-section with a valve overflow	-	315	In stock	Enquiry
TL-YFM35-6-C-111111	Hydraulic directional valve YFM35, 6-section with a valve overflow	-	315	In stock	Enquiry

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A monoblock Directional valve spool YFM35 pilot-operated hand lever of centering springs. Intended for hydraulic systems of cranes, lifts, construction and agricultural machinery, etc.. As standard, equipped with a type C safety valve (set to 140 bar) and type 1 spools. Material: cast iron (body), steel hardened (spools). Sealing: NBR. Maximum working pressure: 315 bar. Maximum return pressure: 25 bar. Operating temperature: from -20°C to +80°C.