Remote Condensing Unit - True GDM Series Technical & Service Manual

INSTALLATION INSTRUCTION

Remote Condensing Unit

For cabinet installation, use instal-
lation instructions with cabinet.
Receiving: Upon receiving this
piece of equipment remove all
outer packaging and inspect for
concealed damage. If damage is
found, indicate such on the carriers
Bill of Lading for claim to be filed.
In order to minimize damage to this
equipment, it is recommended that
the packaging remains in place
until it is in its final location.
Condensing units located indoors
or in confined areas must have ade-
quate ventilation. Condensing units
require 1000 cfm of air per ton of
refrigeration.
True Manufacturing Company
strongly recommends the use of
compressor crankcase heaters and
headmaster valves be used at all
times with a remote compressor
unit. Not using these components
may void the compressor warranty.
Refrigerant Lines: All refriger-
ant piping should be ACR type. It
is recommended that all brazed
joints be made with "hard solder"
such as Silphos or Unibraze.
Solder such as 95-5 or other soft
solders are not recommended.
All suction lines must be insulat-
ed, with at least 1/2" wall insula-
tion. Keep all lines as short as pos-
sible.
Always pitch suction lines down-
ward in the direction of flow.
Generally 1/2" pitch for each 10 ft.
of line is adequate for good oil
return. Field installation vibration
eliminators should be field installed
parallel with the compressor crank
shaft and as close to the compressor
as possible.
Leak Check and Evacuation:
After all refrigerant line connections
have been complete, the entire sys-
tem should be leak checked. This
includes field and factory connec-
tions. Charge system with refrigerant
vapor and add enough nitrogen to
raise pressure to 150 PSIG maxi-
mum.
Leak check the entire system.
Make repairs as necessary.
Evacuation Process:
the proper level of dehydration in the
refrigeration system, a vacuum of at
least 500 microns must be drawn. Do
not use the system's compressor as a
vacuum pump and do not operate
compressor while system is in a vac-
uum.
Open all system service valves to
discharge any pressure in the system.
Connect vacuum pump to high and
low side of system. Pull vacuum.
Break the vacuum with system
refrigerant. Pull vacuum again, down
to 500 microns or lower.
Shut valves before charging.
Charging Process: When initially
charging a system that is in a vacuum,
liquid refrigerant can be added direct-
ly into the receiver tank w i t h o u t
compressor running.
If you have difficulty charging the
correct amount of refrigerant into the
system you may start the system to
complete the charging process.
10
Add the correct amount or until the
sight glass indicates a full charge,
with a clear window, bubbles indicate
more refrigerant is required. Care
should be taken not to overcharge the
system at this point. The evaporator
fans must be operational while charg-
ing; cooler fans must run continuous-
ly, freezer fans will be delayed by the
fan control. Make sure freezer fans
are running during final charg i n g
process.
Keep a close check on suction and
discharge pressures. After system has
stabilized, check for excessive liquid
To obtain floodback to the compressor.
flooding occurs (less than 8˚ super-
heat in freezers, 12˚ in coolers) adjust
expansion valve Clockwise, 1/2 a
turn at a time, recheck before leaving
installation.
Check full load amps on the com-
pressor, this can be found on the com-
pressors nameplate, Check compres-
sor oil level. Normal charge is indi-
cated by 1/2 of the sight glass having
oil in it.
Final Check: Check high and low
pressure control settings. Set thermo-
stat to desired cabinet temperature.
Check defrost timer settings (if appli-
cable). Check voltage, this must be
100% of the nameplate rated voltage
for operation. Anything more or less
should be corrected immediately.
Replace all service valve caps and
secure all unit covers.
If