Liberty Pumps ARC18-Series User Manual

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IMPORTANT: This unit is designed to allow a PRO370 or 380 simplex ejector system to be installed up to 18 inches
below grade in an outdoor installation. It is not a gas or water tight tank extension that increases the capacity of the basin.

The riser provides a convenient underground chamber for the electrical and pipe connections to exit underground and
out-of-sight. A green twist-lock cover can be removed to provide access to plumbing connections, valves and the
electrical junction box.

The riser is sold by itself or as a kit with all the necessary components for a professional installation including elbows,
electrical fittings and a junction box.
Check

with your distributor if you purchased only the riser and would like the optional 2” installation kit.

NOTE: Due to size constraints, only 2” discharge installation kits are available. 3” discharge systems may require that
some components be mounted outside of the riser.

Install the PRO370 or PRO380 sewage system per the instructions included with it. Determine the overall
height of the system and riser when excavating and setting the basin. The cover of the access riser should be at
ground level when backfilling is complete. Burial depth of the

system should not exceed 18” below finished grade.

Determine the discharge, electrical, and vent positions relative to the system. The access riser slides over the
PRO370/380 tank and can be rotated in any direction to simplify plumbing. The riser will rest on the concrete
splash lip of the basin.

Installation of sidewall pipe seal grommets. Once exit positions have been determined for both the vent and
discharge, a 2” pipe seal grommet can be installed by drilling a 3” hole in the sidewall of the riser. The riser has four
flat areas as well as a large ring that runs around the riser to which the discharge pipe or vent can exit. If both a
check and ball valve are required, the discharge needs to exit on the opposite side as illustrated on page 4. To
ease installation of the pipe through the pipe seal grommet, grease the pipe or use liquid soap as a lubricant.

Install the discharge. A short pipe can be threaded into the discharge port of the PRO-Series cover and a 90°
elbow attached. A check valve is recommended to prevent water from back flowing and filling the basin. NOTE: In
northern climates where frost may be a concern, pipes exiting from the side of the system may be exposed to
freezing conditions. If this unit is installed in a frost zone, do not use a check valve. Substitute a union to facilitate
cover removal and pump access. If a check valve is not used, the vertical lift should be minimized to reduce the
amount of back flow after eac

h cycle. A maximum length of 30’ of 2” pipe can be pitched to drain back into the

system. Beyond 30’, discharge piping should be pitched down towards the final discharge destination. A ball valve
is recommended so that back flow can be prevented in the event that the pump or check valve must be removed for
service. When connecting the check valve, ball valve, etc. take care to position items as close to the sidewall of the
riser as possible to allow room for removal of the system cover. Use unions and couplings as necessary to allow for
this.

Connection of vent. To maintain hidden pipes, the vent pipe can be routed underground to an existing household
vent. For a 2” vent, a 3” hole should be drilled in the sidewall of the riser where the vent pipe is to exit. Install the
pipe seal grommet, which is included in the kit. The pipe should be lubricated with liquid soap or grease to ease
pipe installation. A 90° elbow with male threads should be threaded into the vent flange of the system. A rubber slip
coupler is provided and should be installed in the vent piping as illustrated on page 4 to allow easy removal of the
system cover and pump if service is required.

Connection of electrical. A NEMA 4X weatherproof pump station junction box (Liberty model JB120 or JB230) is
recommended. It can be mounted inside or outside of the access riser. If mounting inside, a template is included in
this manual to drill the four mounting holes. If nonmetallic conduit is used it must be mounted in such a fashion as to
be at least 18 inches below grade. Consult the National Electrical Code (NEC) and local codes for further
information. Additional instructions are included with the JB120 or JB230 box. A qualified electrician should perform
all electrical connections.

1. General Information

2. Installation
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