Autotrol 255 / LOGIX 740, Operation Manual, Page: 7 / 92

Drain line connection
1. If the backwash flow rate exceeds 5 gpm (22.7 Lpm) or if the unit is located
20-40 feet (6.1-12.2 m) from drain, use 3/4-inch (1.9 cm) tubing. Use appropriate
fittings to connect the 3/4-inch tubing to the 3/4-inch NPT drain connection on
valve.
2. The drain line may be elevated up to 6 feet (1.8 m) providing the run does not
exceed 15 feet (4.6m) and water pressure at the conditioner is not less than
40 psi (2.76 bar). Elevation can increase by 2 feet (61 cm) for each addditional
10 psi (0.69 bar) of water pressure at the drain connector.
3. Where the drain line is elevated but empties into a drain below the level of the
control valve, form a 7-inch (18 cm) loop at the far end of the line so that the
bottom of the loop is level with the drain line connection. This will provide an
adequate siphon trap.
Where the drain empties into an overhead sewer line, a sink-type trap must
be used.
Secure the end of the drain line to prevent it from moving.
NOTE : Standard commercial practices are expressed here. Local codes may
require changes to the following suggestions. Check with local authorities
before installing a system.
Figure 3
Drain line connection
drain
air gap
WARNING : Never insert drain line directly into a drain, sewer line or trap
(figure 3). Always allow an air gap between the drain line and the wastewater
to prevent the possibility of sewage being back-siphoned into the conditioner.
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