GE Merlin - Manual (Page 6)

6 THE BASIC REVERSE OSMOSIS SYSTEM
Rev B
Drain Connection - Depending on plumbing codes, the waste water
may need to go to drain through an anti-siphon air gap. A detachable
faucet air gap is included with the system. If discharging into the utility
sink or standpipe, an air gap of greater than 1.5 inches above the flood
rim must be provided.
Do not connect the system drain line to the dishwasher drain or near
the garbage disposal. Back pressure from these units may cause the
air gap to overflow.
In restricted under-sink areas, it may be easier to install the faucet first.
Allow adequate tubing lengths for final system placement.
Figure 1 Typical Under-Sink Installation
NOTE: All plumbing should be done in accordance with state and
local plumbing codes.
Some codes may require installation by a licensed plumber; check
with the local plumbing authority prior to installation.