070.610-IOM (JUL 21)
Page 20
RWF II Rotary Screw Compressor Units
Installation
•
First, call the panel manufacturer before drilling into
the panel to be sure you are entering the panel at the
right place.
•
Take measures to avoid ESD (electrostatic discharge) to
the electronics as you prep the inside of the Electronic
control panel. This can be done by employing an anti
-
static wrist band and mat connected to ground.
•
Cover the electronics with plastic and secure it with
masking or electrical tape.
•
Place masking tape or duct tape on the inside of the
panel where you are going to drill. The tape will catch
most of the filings.
•
Clean all of the remaining filings from the panel before
removing the protective plastic.
When routing conduit to the top of an electronic control
panel, condensation must be taken into consideration.
Water can condense in the conduit and run into the panel
causing catastrophic failure. Route the conduit to the
sides or bottom of the panel and use a conduit drain. If
the conduit must be routed to the top of the panel, use a
sealable conduit fitting which is poured with a sealer after
the wires have been pulled, terminated, and the control
functions have been checked. A conduit entering the top
of the enclosure must have a NEMA-4 hub type fitting
between the conduit and the enclosure so that if water
gets on top of the enclosure it cannot run in between the
conduit and the enclosure. This is extremely important in
outdoor applications.
NOTICE
It is simply never a good practice to enter through
the top of an electronic control panel or starter panel
that does not already have knockouts provided. If
knockouts are not provided for this purpose it is
obvious this is not recommended and could VOID
WARRANTY.
Never add relays, starters, timers, transformers, etc.
inside an electronic control panel without first contact
-
ing the manufacturer.
Contact arcing and EMI emitted
from these devices can interfere with the electronics.
Relays and timers are routinely added to electronic control
panels by the manufacturer, but the manufacturer knows
the acceptable device types and proper placement in the
panel that will keep interference to a minimum. If you
need to add these devices, contact the manufacturer for
the proper device types and placement.
Never run refrigerant tubing inside an electronic control
panel.
If the refrigerant is ammonia, a leak will totally
destroy the electronics.
If the electronic control panel has a starter built into
the same panel, be sure to run the higher voltage wires
where indicated by the manufacturer.
EMI from the
wires can interfere with the electronics if run too close to
the circuitry.
Never daisy-chain or parallel-connect power or ground
wires to electronic control panels.
Each electronic
control panel must have its own control power supply and
ground wires back to the power source (Plant Transform
-
er). Multiple electronic control panels on the same power
wires create current surges in the supply wires, which
may cause controller malfunctions. Daisy-chaining ground
wires, taking them to ground at each device, allows
ground loop currents to flow between electronic control
panels which also causes malfunctions. See the following
Figure.
Figure 24: Electronic control panel power supplies
