Table of Contents
Advertisement
NOTE: If compressor is allowed to run in reverse
rotation for an extended period of time, the
compressor's internal protector will trip.
All three phase compressors are wired identically
internally. As a result, once the correct phasing is
determined for a specific system or installation,
connecting properly phased power leads to the same
Fusite terminal should maintain proper rotation direction.
The direction of rotation of the compressor may be
changed by reversing any two line connections to the
wall-mount unit.
Compressor Control Module (CCM)
Delay-on-Make Timer
Short Cycle Protection/Delay-on-Break
Test Mode
High Pressure Detection
Brownout Protection with Adjustment
The LPC terminals are jumpered in this application.
Instead, the low pressure transducer is used for low
pressure monitoring.
Each compressor uses an independent CCM.
Delay-on-Make Timer
In the event of power loss, a delay-on-make timer is
included to be able to delay startup of the compressor.
This is desired when more than one unit is on a
structure so that all of the units do not start at the
same time which could happen after a power loss or
building shutdown. The delay-on-make time period is
2 minutes plus 10% of the delay-on-break time period.
To ensure that all of the units do not start at the same
time, adjust the delay-on-break timer on each unit to a
slightly different delay time.
Short Cycle Protection/Delay-on-Break
An anti-short cycle timer is included to prevent short
cycling the compressor. This is adjustable from 30
seconds to 5 minutes via the adjustment knob (see Figure
39). Once a compressor call is lost, the time period must
expire before a new call will be initiated.
10% of this time is also considered on the delay-on-
make timer (see Delay-on-Make Timer).
High Pressure Detection
High pressure switch monitoring allows for a lockout
condition in a situation where the switch is open. If the
high pressure switch opens, the CCM will de-energize
the compressor. If the switch closes, it will then restart
the compressor after the delay-on-break setting has
expired on the device. If the switch trips again during
the same Y call, the compressor will be de-energized.
The ALR terminal will be energized, signaling the unit
control board that a high pressure event has occurred
(see Refrigerant High Pressure Alarm).
Manual 2100-749
Page
26 of 68
Test Mode
By rapidly rotating the potentiometer (POT) clockwise
(see Figure 39), all timing functions will be removed
for testing.
The conditions needed for the unit to enter test mode
are as follows: POT must start at a time less than or
equal to the 40 second mark. The POT must then be
rapidly rotated to a position greater than or equal to
the 280 second mark in less than ¼ second. Normal
operation will resume after power is reset or after the
unit has been in test mode for at least 5 minutes.
Brownout Protection with Adjustment
Brownout protection may be necessary if the utility
power or generator power has inadequate power to
prevent the voltage from dropping when the compressor
starts. This is rare but can happen if the generator
is undersized at the site or if the site is in a remote
location far from the main power grid. Under normal
circumstances, allowing the brownout to be ignored for
a time period should not be needed. The 8201-169 is
shipped with all the DIP switches in the 'off' or 'do not
ignore' position (see Figure 39).
If ignoring the brownout is needed because of the
above conditions, three preset timers can be set by DIP
switches in order to delay signaling a power brownout
for a specific length of time after compressor contactor
is energized. This allows the compressor a time period
to start even if the voltage has dropped and allows
the voltage to recover. This delay only happens when
the CC terminal energizes. The delay can be set to 1
second (A DIP switch), 5 seconds (B DIP switch) or 10
seconds (C DIP switch); time is not cumulative—only
the longest setting will apply. If the voltage recovers
during the brownout delay period, the compressor will
start.
If a brownout condition is detected by the 8201-169,
the troubleshooting light will flash blue. The light will
continue to flash until the cooling call is satisfied or
power is removed from the Y terminal. This condition
does not prevent operation, it only indicates that a
brownout condition was present at some point during
the cooling call. If a brownout condition is detected,
CC will be de-energized and will retry after the delay-
on-make timer is satisfied; this process will continue
until call is satisfied.
If user chooses the "do not ignore" position (all three
DIP switches "off") when the site has inadequate utility
or generator power, this could lead to the compressor
never starting. The control will see the brownout
immediately and not start.
A common scenario and one that has been seen in the
field is when a unit or units switches from utility power
to generator power. With slower transfer switches, the
time delay between the utility power and generator
power didn't cause a problem. The units lost power,
shut off and came back on line normally. With the
Advertisement
Table of Contents
Troubleshooting
