RTHD-SVX01D-EN 65
Installation Electrical
WARNING
Electrical Shock!
Contacting any of the motor terminals, even with the motor off
can cause a severe, potentially fatal, shock. Follow proper
lockout/tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power before
servicing could result in death or serious injury.
NOTE: IMPORTANT! WHEN EVACUATING THE CHILLER’S REFRIG-
ERANT SYSTEM, ALWAYS HAVE THE MAIN POWER DISCONNECT/
CIRCUIT BREAKER OPENED.
Even when the compressor is not running, voltage is present at the
compressor motor terminals, providing the potential for current to flow
through a low impedance path.
When removing refrigerant for the chiller both the condenser and chilled
water pump must be operating to avoid freeze up.
As the chiller is evacuated below atmospheric pressure, the dielectric
strength (resistance to arcing) of the gaseous atmosphere is significantly
reduced. Because the SCRs are connected “inside the delta,” three of the
motor terminals are connected directly to the line voltage. An “arc over” can
occur between motor terminals under conditions seen in the evacuation pro-
cess. If this occurs the circuit breaker (or other external protective devices)
will trip in response to high fault currents, and motor damage may also occur.
This can be avoided through being certain that the chiller is fully discon-
nected from all power sources before beginning pumpdown or evacua-
tion procedures, as well as guaranteeing that the disconnect cannot be
accidentally closed while the chiller is in a vacuum.
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