Whirlpool MET3800XW0 Installation Instructions Manual page 7

SYSTEM
Drain system can be installed using a floor drain, wall standpipe,
floor standpipe, or laundry tub. Select method you need.
Floor standpipe drain system
Minimum diameter for a standpipe drain: 2" (51 mm). Minimum
carry-away capacity: 17 gal. (64 L) per minute. Top of standpipe
must be at least 39" (990 mm) high; install no higher than 96"
(2.4 m) from bottom of washer/dryer. If you must install higher
than 96" (2.4 m), you will need a sump pump system.
Floor drain system
Floor drain system requires a Siphon Break Kit (Part Number
285834), 2 Connector Kits (Part Number 285385), and an
Extension Drain Hose (Part Number 285863) that may be
purchased separately. To order, please see toll-free phone
numbers in your "Use and Care Guide." Minimum siphon break:
28" (710 mm) from bottom of washer/dryer. (Additional hoses
may be needed.)
Wall standpipe drain system
See requirements for floor standpipe drain system.
Laundry tub drain system
Minimum capacity: 20 gal. (76 L). Top of laundry tub must be
at least 39" (990 mm) above floor; install no higher than 96"
(2.4 m) from bottom of washer/dryer.
IMPORTANT: To avoid siphoning, no more than 4.5" (113 mm)
of drain hose should be inside standpipe or below the top of
wash tub. Secure drain hose with shipping strap.