R983032396 2FRM6A36-2X/3QRV-IN001 Rexroth German made speed control valve

FAQ — Frequently Asked Questions

Q1: What is the difference between "A" and "B" versions of 2FRM6?

A:

• 2FRM6A…​ = Throttling in A → A₁​ direction (meter-in on Port A). Used when the valve is stacked on the A-port side between directional valve and subplate.

• 2FRM6B…​ = Throttling in B → B₁​ direction (meter-in on Port B).

  For speed control on both extend and retract, two valves (one A + one B) are typically stacked. The free-flow return direction always has an open check valve.

Q2: Why does this valve need an external drain (Y port) and what happens if I omit it?

A:​ The pressure compensator spool​ balances spring force against pilot/drain pressure. The Y port must be connected directly to tank with zero backpressure. If Y is blocked or sees backpressure, the compensator cannot function correctly → flow becomes pressure-dependent and unstable. Never plug the Y port on a 2FRM valve.

Q3: How is this different from a Z2FS6 needle throttle valve?

A:​ The 2FRM6 has a pressure compensator​ that maintains a constant pressure drop across the metering orifice. This means the set flow stays constant despite load pressure changeson P or A ports. A Z2FS6 is a simple needle/throttle — flow varies with ∆P. Use 2FRM when consistent speed under varying load is required; use Z2FS for coarse, cost-sensitive throttling.

Q4: What is the practical meaning of the "3Q" flow code?

A:​ /3Q​ sets the maximum adjustable flow to 3 L/min. The usable range is approx. 0.05–3.0 L/min. Select the Q-code closest to your required max flow — a smaller Q-range gives better fine-adjustment resolution. If you need 6 or 16 L/min, choose /6Q or /16Q variants. Do not try to use a 3Q valve for flows >3 L/min.

Q5: Why FKM (Viton) seals on this valve?

A:​ The V suffix = FKM seals, required for:

• Service temperatures above +70°C (up to +80°C)

• Water glycol (HFC)​ or phosphate ester (HFD)​ fire-resistant fluids

  For standard mineral oil (HL/HLP) at normal temps, the NBR version is acceptable. The FKM version (this part) provides broader fluid compatibility and higher temp rating — choose based on your fluid & temperature.