Liquid Controls LCR Install - Manual (Page 16)

16
Guidelines for Environmental Sealing
The LCR contains a printed circuit board with sensitive
electronic components that can be damaged by the
presence of moisture. Conformal coating on the board
and a moisture-absorbing desiccant inside the enclosure
mitigates the problem of moisture corroding the LCR
board. These measures protect the board from small
amounts of moisture trapped inside when the lid is closed
in humid conditions, but are not adequate in protecting
the unit over time if a continuing leak in the enclosure is
present. Therefore, it is necessary to adequately seal
all openings to the unit during installation. The LCR is
rated NEMA 4x making it capable of pressure washing
when seals are adequately applied, as described below.
1. Conduit Entrances
The LCR has seven conduit entrances each with 1/2 -
14 NPT female threads. Use only 1/2 - 14 NPT male
threaded fittings on all conduit entrances. Pressed in
Caplugs are inadequate as seals for these entrances.
Straight rather than tapered threads are also inadequate.
Acceptable fittings are either metal or plastic conduit, pipe
plugs, or cable glands. Threads should be treated with
a Teflon based “pipe dope” or taped using a minimum of
two revolutions of Teflon tape prior to installation. Threads
should be engaged a minimum of four full turns. When
using cable glands be sure that the gland is sized properly
for the outside diameter of the cable being sealed and
that the elastometric seal around the cable sheath is
compressed onto the cable. Use only one cable per cable
gland unless the gland is designed for multiple cables.
When using conduit or Liquid-Tite make sure that the
opposite end is going into an environmentally sealed
device as well. For example, some solenoid valves are
rated for hazardous locations but may not be sealed
environmentally. If the conduit is not sealed on the other
device, fill the interior of the conduit at the LCR with a
silicone rubber sealant such as RTV to prevent moisture
from running down the conduit into the LCR
enclosure.Refer to “Wiring The LCR” notes on page 10
for code requirements.
2. Cover Seals
The covers on both the LCR and its Remote Electronic
Counter (REC) are provided with 0-ring seals to prevent
moisture ingress. The LCR O-ring must be inserted in
the groove of the cast housing
prior to the cover being attached. All twelve bolts must
be tightened to compress the cover O-ring adequately.
The O-ring on the REC is integral to the REC cover. All
four cover screws must be tightened to effect a seal on
the REC cover.
3. Shaft Seals
Units with internal pulsers have an O-ring seal around
the pulse encoder drive shaft emanating from the bottom
of the LCR. Various drivers can be attached to this shaft
to adapt to industry standard PD flow meters. When
installing a driver make sure not to remove the O-ring
that is around the drive shaft embedded in the base
casting. The O-ring should be seated in the counter bore
in the casting and covered with the flat washer provided
before attaching a driver using the cotter pin. The control
switch on the front of the LCR is also sealed with an O-
ring that is held in place by a bushing secured with three
socket head cap screws. In the event that a control switch
is replaced in the field, make sure that the O-ring is in
place on the switch shaft before reinstalling the switch
bushing.