SCXF-SVX01Q-EN
81
Startup
WWAARRNNIINNGG
LLiivvee EElleeccttrriiccaall CCoommppoonneennttss!!
FFaaiilluurree ttoo ffoollllooww aallll eelleeccttrriiccaall ssaaffeettyy pprreeccaauuttiioonnss
wwhheenn eexxppoosseedd ttoo lliivvee eelleeccttrriiccaall ccoommppoonneennttss ccoouulldd
rreessuulltt iinn ddeeaatthh oorr sseerriioouuss iinnjjuurryy..
WWhheenn iitt iiss nneecceessssaarryy ttoo wwoorrkk wwiitthh lliivvee eelleeccttrriiccaall
ccoommppoonneennttss,, hhaavvee aa qquuaalliiffiieedd lliicceennsseedd eelleeccttrriicciiaann
oorr ootthheerr iinnddiivviidduuaall wwhhoo hhaass bbeeeenn pprrooppeerrllyy ttrraaiinneedd
iinn hhaannddlliinngg lliivvee eelleeccttrriiccaall ccoommppoonneennttss ppeerrffoorrmm
tthheessee ttaasskkss..
NNOOTTIICCEE
CCoommpprreessssoorr DDaammaaggee!!
FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww wwiillll ccaauussee tthhee
ccoommpprreessssoorr ttoo ooppeerraattee iinn aa vvaaccuuuumm aanndd rreessuulltt iinn
ccoommpprreessssoorr ddaammaaggee..
NNeevveerr mmaannuuaallllyy oorr aauuttoommaattiiccaallllyy ppuummpp ddoowwnn
ssyysstteemm bbeellooww 77 ppssiigg..
NNOOTTIICCEE
CCoommpprreessssoorr DDaammaaggee!!
FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss ccoouulldd rreessuulltt iinn
ccoommpprreessssoorr ddaammaaggee..
KKeeeepp ccrraannkkccaassee hheeaatteerrss oonn wwhheenneevveerr rreeffrriiggeerraanntt iiss
iinn tthhee ssyysstteemm..
IIff ccrraannkkccaassee hheeaatteerrss hhaavvee nnoott bbeeeenn oonn wwiitthh
rreeffrriiggeerraanntt iinn tthhee ssyysstteemm,, ttuurrnn tthhee ccrraannkkccaassee
hheeaatteerrss oonn ffoorr aa mmiinniimmuumm ooff 2244 hhoouurrss bbeeffoorree
ssttaarrttiinngg ccoommpprreessssoorrss..
To start the unit, complete the following steps in order.
Review “Preliminary Refrigerant Charging,” p. 41, if
applicable. Confirm all steps were completed.
Air-Cooled Only
• Charging is more accurate at higher outdoor
temperatures. If outdoor temperature is < 80°F,
temporarily disable fan pressure control switches.
See unit wiring diagrams and disconnect the wires
between switches and terminal strip.
• Do not attempt to charge system with low ambient
dampers operating (if applicable). Disable these
dampers in “Open” position before proceeding.
• Evaporator load should be at least 70°F return air,
350 CFM/ton.
• Work on only one circuit at a time. See section
“General Data,” p. 14 for compressor sequencing.
NNoottee:: R-410A compressors have belly band crankcase
heaters that must be energized 24 hours before
starting compressor. Power to the unit will
energize the heaters. Heaters will be energized
during the off-cycle as long as the unit has power.
Failure to perform these pre-start instructions
could result in compressor damage.
1. Verify compressor crank case heaters have been on
for at least 24 hours.
2. Make sure all service valves are open.
3. Attach a thermocouple type temperature sensor on
liquid line close to liquid line service valve. To
ensure an accurate reading, clean line where sensor
is attached. After securing sensor to line, insulate
sensor and line to isolate it from ambient air.
4. Attach service gauges to suction and discharge
ports.
5. Check low side pressure. Low pressure cutout
opens below, and closes above, values in Table 35,
p. 62. If the low side pressure is less than the open
psig, refrigerant may need to be added to the
suction line before starting the compressor(s) to
close the switch. SLOWLY meter into the suction
line only as much R- 410A as needed to close the
low pressure cutout. Use the VAPOR charging
connection. If possible, plan to use this entire
refrigerant bottle on the same unit in order to
minimize fractionalization. Use an accurate scale to
measure and record amount of R-410A added.
6. Switch the field supplied unit disconnect to “OFF”.
Open the unit control box and plug in the reset
relay for only the circuit being started
WWAARRNNIINNGG
HHaazzaarrddoouuss VVoollttaaggee!!
FFaaiilluurree ttoo ddiissccoonnnneecctt ppoowweerr bbeeffoorree sseerrvviicciinngg ccoouulldd
rreessuulltt iinn ddeeaatthh oorr sseerriioouuss iinnjjuurryy..
DDiissccoonnnneecctt aallll eelleeccttrriicc ppoowweerr,, iinncclluuddiinngg rreemmoottee
ddiissccoonnnneeccttss bbeeffoorree sseerrvviicciinngg.. FFoollllooww pprrooppeerr
lloocckkoouutt//ttaaggoouutt pprroocceedduurreess ttoo eennssuurree tthhee ppoowweerr
ccaann nnoott bbee iinnaaddvveerrtteennttllyy eenneerrggiizzeedd.. VVeerriiffyy tthhaatt nnoo
ppoowweerr iiss pprreesseenntt wwiitthh aa vvoollttmmeetteerr..
7. Turn 115 volt control circuit switch “ON”. Close
control box and switch field supplied unit
disconnect “ON”. Unit power should be off no
longer than 60 minutes to prevent refrigerant
migration to compressor sumps. If power is off for
longer than 60 minutes, allow time for crankcase
heaters to drive refrigerant from compressor sumps
before starting compressors.
8. Adjust setpoints at the HI.
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