Product Design - Daikin ComfortNet DX7TC Service Instructions Manual

PRODUCT DESIGN

This section gives a basic description of cooling unit operation,
its various components and their basic operation. Ensure your
system is properly sized for heat gain and loss according to
methods of the Air Conditioning Contractors Association (ACCA)
or equivalent.
CONDENSING UNIT
The condenser air is pulled through the condenser coil by a
direct drive propeller fan. This condenser air is then discharged
out of the top of the cabinet. These units are designed for free
air discharge, so no additional resistance, like duct work, shall be
attached.
The suction and liquid line connections on present models are of
the sweat type for field piping with refrigerant type copper. Front
seating valves are factory installed to accept the field run copper.
The total refrigerant charge for a normal installation is factory
installed in the condensing unit.
DX16TC, DZ16TC, DX18TC, DZ18TC models are available in
2 through 5 ton sizes and use R-410A refrigerant. They are
designed for 208/230 volt single phase applications.
DX16TC, DZ16TC, DX18TC, DZ18TC R-410A model units use
the Copeland Scroll "Ultratech" Series compressors which are
specifically designed for R-410A refrigerant. These units also
have Copeland® ComfortAlert diagnostics. The Copeland®
ComfortAlert diagnostics are integrated into the unitary (UC)
control. These models are ComfortNet™ ready.
There are a number of design characteristics which are different
from the traditional reciprocating and/or scroll compressors.
"Ultratech" Series scroll compressors will not have a discharge
thermostat. Some of the early model scroll compressors required
discharge thermostat.
"Ultratech" Series scroll compressors use "POE" or polyolester
oil which is NOT compatible with mineral oil based lubricants like
3GS. "POE" oil must be used if additional oil is required.
The DX16TC, DZ16TC, DX18TC, DZ18TC series split system units
use a two-stage scroll compressor. The two-step modulator has
an internal unloading mechanism that opens a bypass port in the
first compression pocket, effectively reducing the displacement
of the scroll. The opening and closing of the bypass port is
controlled by an internal electrically operated solenoid.
The ZPS two-step modulated scroll uses a single step of
unloading to go from full capacity to approximately 67% capacity.
A single speed, high efficiency motor continues to run while the
scroll modulates between the two capacity steps.
A scroll is an involute spiral which, when matched with a mating
scroll form as shown, generates a series of crescent shaped gas
pockets between the two members.
During compression, one scroll remains stationary (fixed scroll)
while the other form (orbiting scroll) is allowed to orbit (but not
rotate) around the first form.
FIGURE A
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