HVAC
30,000 BTU Air Conditioning
Stay cool in any climate with powerful cooling capacity.
2026 Forest River Sandpiper 3990FL
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Layout & Media
Explore the floorplan, 3D tour
Complete Fifth Wheel Specifications
2026 Forest River Sandpiper Overview
Introducing the 2026 Forest River Sandpiper 3990FL, a stunning new addition to the fifth wheel category. With a spacious length of 43.5 ft and a dry weight of 12,439 lbs, this RV is perfect for family adventures, comfortably sleeping 8 individuals. Equipped with a powerful 30,000 BTU air conditioning and a 40,000 BTU heater, it ensures year-round comfort. The Sandpiper's generous black and fresh water capacities of 50 gallons each make it ideal for extended trips away from home. Experience the freedom of the open road and create lasting memories with family and friends. Schedule your tour today!
Premium Features & Highlights
Sleeps up to 8 for family-friendly trips
30,000 BTU Air Conditioning for year-round comfort
40,000 BTU Heater to keep you warm in colder months
50-Gallon Fresh Water Capacity for extended off-grid adventures
50-Gallon Black Water Capacity for convenience
Select a category to view specs
Overview
Vehicle Identification & Details
8 specifications available
- Category
- Fifth Wheel
- Condition
- new
- Floorplan
- 3990FL
- Make
- Forest River
- Model
- Sandpiper
- Stock Number
- SP-048782
- VIN
- 4X4FSAS26TJ048782
- Year
- 2026
Size & Weight
Dimensions, Weight, Construction & Exterior
10 specifications available
- Dry Weight
- 13,063 lbs
- GVWR
- 15,375 lbs
- Length
- 43.5 ft
- Width
- 8 ft
- Awning Length Ft
- 21 ft
- Awnings Count
- 1
- Doors Count
- 1
- Primary Color
- White
- Slides
- 5
- Hitch Weight
- 2,825 lbs
Sleeping & Layout
Beds, Layout, Living & Comfort
14 specifications available
- Bedroom Count
- 1
- Bunk Beds Count
- 0
- Convertible Beds Count
- 0
- Double Beds Count
- 0
- Bunkhouse
- Yes
- Full Beds Count
- 0
- King Beds Count
- 1
- Primary Bedroom Location
- Rear
- Queen Beds Count
- 0
- Sleeps
- 8
- Has Primary Bedroom Window Shades
- Yes
- Living Area Location
- Front
Kitchen & Dining
Cooking, Dining & Appliances
4 specifications available
- Microwave
- Yes
- Stovetop Burners
- 3
- Refrigerator Size
- 16 cu ft
- Refrigerator Type
- 12V Stainless
Bathroom & Facilities
Comfort & Privacy
4 specifications available
- Bathrooms Count
- 1
- Has Bathroom Vent
- Yes
- Has Medicine Cabinet
- Yes
- Shower Type
- Shower w/Seat
Water Systems
Tanks & Plumbing
8 specifications available
- Black Water Capacity
- 50 gal
- Black Water Tanks Count
- 1
- Fresh Water Capacity
- 50 gal
- Fresh Water Tanks Count
- 1
- Gray Water Capacity
- 80
- Gray Water Tanks Count
- 1
- Has Water Heater Bypass
- Yes
- Water Heater Type
- On Demand Tankless
Power & Electrical
Electrical, Entertainment & Safety
9 specifications available
- Ac Prewiring
- Yes
- Cable Prewiring
- Yes
- Has Battery Converter
- Yes
- Heat Prewiring
- Yes
- Satellite Prewiring
- Yes
- Tv Antenna Prewiring
- Yes
- Washer Dryer Prewiring
- Yes
- Radios Count
- 0
- Televisions Count
- 0
Climate Control
Heating & Cooling
2 specifications available
- Ac Btu
- 30,000 BTU
- Heater Btu
- 40,000 BTU
Manufacturer Features & Equipment
5/8" tongue and groove DryMax® OSB floor decking
2 x 3 floor joists, 12" on center
Smoke alarm
Fire extinguisher
Two chairs in place of ottoman bench, Cordless vacuum, Slide room awnings (N/A dinette slides), Washer and Dryer (Standard on 3800RK & 3900HBLR), Dual pane windows (N/A 3900HBLR 84” Window), 3rd A/C power saver direct dump system w/ wall thermostat,
Automatic Electric Level-Up System, 2" Towing and Accessory Hitch (Where Available), 7,000lb axles with Anti-lock Braking System, Goodyear Radial Tires w/ anti-lock brakes, Lippert auto adjust brakes, Rich Solar 200W roof mounted solar panel with controller and battery, Quad MORryde® step above with strut (Where Available), Color matched high gloss gel coated colored exterior fiberglass, Painted two tone aerodynamic fiberglass front cap with improved turning radius, Underbelly Armor, Tire Pressure Monitoring System, Spare tire, Large, tinted windows with 80/20 UV prohibitor, Electric awning with LED light strip, Prepped for Lippert On-The-Go Ladder, Power front jacks with spring loaded pins, Automotive-style fender skirts, Hitch light, Porch light with interior switch, 30 lb. double LP tanks with auto change over, Rain gutters with extra-long drip spouts (Prevents black streaking), Insulated heavy duty slam lock baggage doors, Exterior foldable grab handle, Unobstructed pass-through storage area, Upgraded aluminum rims, Oversized friction hinge entry door with extended latch (Main Entry), Exterior LP Quick Connect,
Solid Surface Kitchen Counter tops, Fiberglass one-piece shower, Washer and Dryer Prep, 7’ slide-out height (Main Slides), Stainless steel kitchen package, Beachside Sundance Congoleum linoleum, Hidden hinged, soft close drawers and cabinets, Full extension ball bearing drawer guides, Stainless steel under mounted kitchen sink, Trash receptacle in kitchen, Decorative backsplash, Two color coordinated interiors, LED lighting throughout, Recessed residential lighting, Accent lighting over dinette, Extra-large, panoramic picture windows throughout, Vented side windows in slide-outs, TV antenna with booster, Solid wood drawer fronts with birch sides, Solid wood, square inset cabinet doors, painted or wood grain, Bedroom slide-out fascia, Memory foam mattress, 50" flatscreen smart TV (65” 3900HBLR), JBL Aura Cube FM/Bluetooth media center, Designer window treatment, Ceiling fan, Tri-fold hide-a-bed sofa, Quilted bedspread, Prepped for inverter, Teddy Bear® bunk mats,
Dual ducted 15k BTU Air Conditioners, prepped for 3rd 15k BTU A/C, AIRDIRECT® Air Vents for improved efficiency, 16 cu. ft. 12V refrigerator, 60,000BTU On Demand Tankless Water Heater, 40,000BTU furnace, Heated Holding Tanks (12V), Floor ducted 40,000BTU furnace, 30" OTR stainless steel microwave, Chef collection 3 burner / 24" oven with drawer, Interior monitor panel for holding tanks, Satellite and cable hookup with RG-6 cable for high quality picture, Porcelain foot flush toilet(s), 65 Amp converter, Power fan in Kitchen and Bathroom(s),
Features and equipment are provided by the manufacturer for this model line and may include optional equipment or items that vary by floorplan and trim. Please confirm with Johnston RV Center which options are included on this unit.
* Vehicle specifications listed to the best of our knowledge. All specifications, features, and information are provided by the manufacturer. Johnston RV Center is not responsible for manufacturer defects, specification changes, or recalls. Buyers should verify all information directly with Johnston RV Center.
Built to Last
Superior construction for years of adventures
HVAC
40,000 BTU Heater
Ensure warmth and comfort during colder months.
Plumbing
50-Gallon Fresh Water Tank
Extended off-grid capability for longer trips.
Plumbing
50-Gallon Black Water Tank
Convenient waste management for your travels.
Manufacturer and/or stock photographs may be used and may not be representative of the particular unit being viewed. We are not responsible for any misprints, typos, or errors found in our website pages. Any price listed excludes sales tax, registration tags, and delivery fees. Manufacturer pictures, specifications, and features may be used in place of actual units on our lot. Please contact us for availability as our inventory changes rapidly. All calculated payments are an estimate only and do not constitute a commitment that financing or a specific interest rate or term is available.
$68,858
est $495/mo
