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The Valterra 2" Swing Check Valve – Slip x Slip (SKU 70387, MPN 200-C20) is a professional-grade PVC backflow prevention valve for pond pump discharge lines, waterfall plumbing, pressurized filters, and UV systems. The swing/spring combination design — featuring a hinged EPDM-sealed disc with 1/2 lb return spring — allows installation in horizontal or vertical (upward flow) orientations, making it one of the most versatile check valve options for pond plumbing. Maximum working pressure: 150 PSI. The clear Schedule 40 PVC body is a practical advantage over opaque valves: you can visually verify that the flapper is opening fully during pump operation and seating correctly on shutdown — without removing the valve from service. Solvent-weld slip connections provide a permanent, high-strength bond to standard 2" Schedule 40 or 80 PVC pipe. SKU 70387 / MPN 200-C20 2” Slip × Slip 150 PSI Max EPDM Seal Swing/Spring Combo Clear Sch 40 PVC 6” H × 4.5” W ✅ Why the spring matters: The Valterra 200-C20 is a swing/spring combination valve — not a pure swing valve. The 1/2 lb return spring enables reliable closure in any installation position, including horizontal pipelines where a spring-free swing valve might not close fully. This is the key functional difference between this valve and lower-cost swing-only alternatives. Key Features & Benefits 🔒 Backflow Prevention & Pump Protection When a pump shuts down, water in the discharge line wants to flow backward through the pump impeller. Reverse flow can unwind the impeller, damage seals, and cause "water hammer" pressure surges as flow abruptly reverses. A check valve stops the column of water the moment forward flow ceases, protecting the pump and preventing siphoning that could drain the pond or waterfall. 🔄 Swing/Spring Combination — Any Position The 1/2 lb return spring supplements gravity in closing the EPDM disc, allowing reliable seating in horizontal installations where a spring-free swing valve relies entirely on backpressure to close. The spring tension is light enough to open with minimal pump head pressure while strong enough to close the disc fully between pump cycles. Rated for horizontal, vertical upward flow, and any angle between. 👁️ Clear Body — Visual Confirmation The transparent Schedule 40 PVC body lets you see the swing disc position at a glance: disc fully open during pump operation confirms no flow restriction; disc fully seated on shutdown confirms a complete seal. This is particularly useful during troubleshooting — if the disc is visibly stuck open or closed, you can diagnose it without removing the valve. Valterra is the only major manufacturer offering clear-body check valves in this format. 🛡️ EPDM Seal — Outdoor Durability EPDM (ethylene propylene diene monomer) is specifically formulated to resist UV radiation, ozone, and weathering — the conditions pond plumbing faces year-round outdoors. Unlike Buna-N (NBR) seals that can harden and crack after prolonged outdoor UV exposure, EPDM maintains elasticity and sealing performance across years of outdoor service, including in chlorinated or treated pond water. ⚙️ 150 PSI Rated — Pump-Proof Rated to 150 PSI working pressure at 73°F, this valve handles the output of virtually any pond pump — most submersible and external pond pumps operate at 5–30 PSI. The 150 PSI rating provides a substantial safety margin for pressurized filter systems, UV units, and any configuration with significant back-pressure. Note: PVC pressure ratings decrease at elevated temperatures; for ponds with heated water, consult Valterra's temperature-derating chart. 🔧 Permanent Slip x Slip Bond Solvent-weld (slip) connections create a molecular bond between the valve socket and PVC pipe that is stronger than the pipe itself when cured correctly. Use standard medium-body PVC cement with PVC primer on clean, dry pipe ends. Cure time before pressurizing: 15–30 minutes at room temperature; full cure 24 hours. Plan valve position before cementing — once bonded, the connection is permanent. Technical Specifications Specification Value SKU (PPD) 70387 Valterra MPN 200-C20 Connection Type 2” Slip × Slip (solvent-weld) Body Material Schedule 40 PVC (clear) Valve Type Swing/Spring Combination Check Valve Seal Material EPDM (ethylene propylene diene monomer) Spring Tension 1/2 lb Max Working Pressure 150 PSI at 73°F Dimensions ~6” H × 4.5” W Compatible Pipe 2” Schedule 40 or Schedule 80 PVC Installation Positions Horizontal • Vertical (upward flow only) Vertical Downward Flow NOT suitable — disc will remain open Installation Orientation Guide Orientation Flow Direction Suitability Notes Horizontal Either direction (follow arrow) ✅ Preferred Most common pond installation. Hinge pin at top for best disc swing. Spring ensures reliable closure. Vertical Upward only ↑ ✅ Suitable Flow pushes disc open upward; gravity + spring close disc on shutdown. Follow flow arrow. Vertical Downward ↓ ❌ Not suitable Gravity holds disc open permanently. No backflow prevention. Will not function as intended. Installation Tips Check flow arrow: The arrow cast or printed on the valve body indicates required flow direction — match it to your pump discharge direction PVC cement & primer: Use standard medium-body PVC cement with PVC primer for a reliable bond; apply primer first, then cement, and push/twist pipe fully into socket Cure before pressurizing: Allow cemented joints to set at least 15–30 minutes before turning on the pump; 24 hours for full cure strength Position in horizontal runs: In horizontal pipelines, orient the valve so the hinge is at the top (12 o'clock position) for the smoothest disc swing and best seal Install accessible location: Place the valve where it can be visually inspected through the clear body — in a pump vault or accessible plumbing run rather than buried or hidden Locate downstream of pump: Install on the pump discharge (pressure) side — not on the suction/intake side where it can create cavitation risk Frequently Asked Questions Why is a check valve necessary for pond pumps? A check valve on the pump discharge line serves three critical functions: Prevents backflow on shutdown: When the pump stops, water in the discharge pipe wants to flow backward. The check valve snaps closed, stopping the water column and protecting the pump impeller from reverse rotation. Prevents siphoning: In systems where the discharge line runs above the water level (waterfall return), siphoning can drain the pond or waterfall reservoir when the pump is off. The check valve stops this immediately on shutdown. Reduces water hammer: Abrupt backflow reversal creates pressure surges (water hammer) that can crack fittings and damage equipment. The check valve's rapid closure — aided by the 1/2 lb spring — stops the reverse flow before it builds momentum. Can the Valterra 2" Check Valve be installed vertically? Yes — but only with upward flow direction. The 200-C20's swing/spring combination design enables multi-position installation. ✅ Vertical with upward flow: Water flowing upward pushes the disc open; when flow stops, gravity and the 1/2 lb spring pull the disc back to its seat, sealing against backflow. Follow the flow arrow on the valve body — it must point upward in this installation. ❌ Vertical with downward flow — NOT suitable: Gravity would hold the disc open permanently, providing no backflow protection. Never install with the flow arrow pointing downward in a vertical line. Horizontal: The preferred position for most pond installations. Orient the hinge pin at the top (12 o'clock) in horizontal runs for optimal disc swing. Does this check valve significantly reduce water flow (GPH)? The Valterra 200-C20 is designed for low flow restriction. The swing disc opens to allow nearly unobstructed flow through the 2" bore when the pump is running, and the 1/2 lb spring tension is light enough that very low pump pressure opens it fully. All check valves create some flow restriction — a valve that claims zero resistance is not physically accurate for any swinging disc design. The practical impact for pond pump applications is negligible: a 2" pipe carrying typical pond flow rates (1,000–4,000 GPH) will see minimal measurable GPH reduction across this valve. If your system is extremely flow-sensitive, consider sizing up to a 3" valve with a reducer. Is this check valve compatible with Schedule 40 PVC? Yes — the 2" slip sockets accept standard 2" Schedule 40 or Schedule 80 PVC pipe (both use the same outer diameter). Use standard medium-body PVC cement and PVC primer — any reputable brand works equally well (Weld-On, Oatey, IPS, or equivalent). Installation steps: Cut pipe square and deburr the end Dry-fit the valve to check orientation and flow arrow alignment Apply PVC primer to both the pipe end and valve socket; allow to tack-dry (~15 seconds) Apply PVC cement to pipe end and socket; immediately push pipe fully into socket with a 1/4 turn Hold for 30 seconds; do not pressurize for at least 30 minutes How do I maintain or inspect the internal flapper? The clear PVC body is your best maintenance tool — visually inspect the disc while the pump is running and again when it shuts off: Disc fully open during pump operation: ✅ Normal. The disc should swing fully open and remain stable at operating flow. Disc chattering or fluttering: Flow velocity may be too low for the valve size; consider a smaller check valve or increasing pump speed. Disc not fully seating on shutdown: Debris may be holding it open. Turn off the pump, inspect through the clear body, and flush the line if needed. Prevent debris from entering the valve by installing a pump pre-filter (such as a Matala EZ Bio pre-filter) upstream of the pump intake. String algae in particular can foul check valve discs if it enters the plumbing system. Why Buy from Pond Pro Direct? Authentic Valterra products — genuine PVC valve components Expert pond plumbing guidance — call or text (765) 508-4352, Mon–Fri 9am–5pm EST Free shipping on all orders Price match guarantee on identical products 30-day return period on eligible items