Carrier SUPRA 750Mt, Operation And Service Manual

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4 4--1 15 5 6 62 2----6 61 11 1X XX X----2 20 0 ((0 03 3//0 04 4))
1. 1. Cylin Cylinder dervalve valve and and gau gauge ge
2. 2. Pressu Pressure re reg regula ulator tor
3. 3. Nitr Nitroge ogen n cylin cylinder der
4. 4. Pressu Pressure re gau gauge ge
(0 to 400 psig = 0 to 28 kg/cm (0 to 400 psig = 0 to 28 kg/cm
2 2
))
5. 5. Blee Bleed-Of d-Off f valve valve
6. 6. 1/4 1/4 inch inch conn connectio ection n
1. 1.
2. 2.
3. 3.
4. 4.
5. 5.
6. 6.
Figure 4-1 Figure 4-10 0 Ty Typical set pical setup for testing high up for testing high
pressure switch pressure switch
a. a. Remove switc Remove switch as outlined in section 4.13.1. h as outlined in section 4.13.1.
b. b.
Conne Connect ohmmeter or ct ohmmeter or contin continuity light across switch uity light across switch
termina terminals. ls. Ohmmete Ohmmeter r will indicate resistanc will indicate resistance and e and
continuity light will be lighted if switch closed after continuity light will be lighted if switch closed after
relieving pressure.
relieving pressure.
c. c. Connect switch to a cylinder of dry nitrogen (see Connect switch to a cylinder of dry nitrogen (see
Figure 4-10). Figure 4-10).
d. d. Set nitrogen pressure regulator higher than cutout Set nitrogen pressure regulator higher than cutout
poi point nt on on swi switch tch bei being te ng tested sted.. Pres Pressur sure swi e switch tch cuto cutout ut
and cut-in points are shown in section 2.3. and cut-in points are shown in section 2.3.
e. e.
Close valve on cylinder and open bleed-off valve. Close valve on cylinder and open bleed-off valve.
f. f.
Open cylinder valve. Slowly close bleed-of Open cylinder valve. Slowly close bleed-off valve f valve
and incre and increase press ase pressure until the s ure until the switch witch opens opens. If . If light light
is used, light will go is used, light will go out and if out and if an ohmmete an ohmmeter is r is used, used,
the the me meter ter wi will ll in indi dica cate te op open en. . Ope Open n pre pressu ssure re on on
gau gauge. ge. Slo Slowly wly ope open n ble bleed- ed-off off val valve ve (to (to dec decrea rease se
pre press ssur ure) e) un until til sw switc itch h cl clos oses es (l (lig ight ht wi will ll liligh ght t or or
ohmmeter will move). ohmmeter will move).
4.14 4.14 CHE CHECKIN CKING AN G AND RE D REPLACI PLACING LOW NG LOW
PRESSURE CUTOUT SWITCH PRESSURE CUTOUT SWITCH
4.1 4.14.1 4.1 Rep Replac lacing ing low low pre pressu ssure re swi switch tch
a. a. Unplug Unplug
b. b. Unscrew Unscrew
c. c. Calibr Calibrate new sensor (refer to section 3.18.4) ate new sensor (refer to section 3.18.4)
d. d. Screw into place Screw into place
e. e.
Connect Connect
4.1 4.14.2 4.2 Che Checki cking ng low low pre pressu ssure re swit switch ch
a. a.
Start the unit after having instal Start the unit after having installed a manometer on led a manometer on
compressor. compressor.
b. b.
Close receiv Close receiver valve to er valve to pump down suction line. pump down suction line.
c. c.
Using an ohmmeter or continuity light, verify that Using an ohmmeter or continuity light, verify that
switch opens or switch opens or closes accordi closes according to ng to speci specification fication..
d. d.
Repeat checkout procedure until switch actuates at Repeat checkout procedure until switch actuates at
correct gauge reading. correct gauge reading.
e. e. After switch is adjusted, place a small amount of After switch is adjusted, place a small amount of
pa pain int t or or gl glyc ycero erol l on on the the ad adju justi sting ng scr screw ew so so tha thatt
vibrati vibration will on will not change switch not change switch setting setting..
4.15 4.15 REPLA REPLACING CING RECE RECEIVER IVER SIGHT SIGHT GLASS GLASS
ASSEMBLY ASSEMBLY
NOTE NOTE
There are two types of receiver sight glasses; the There are two types of receiver sight glasses; the
fl
floa oati ting ng ba ball ll ty type pe, , an and d th the e pr pris ism m ty type pe; ; bo both th ar are e
interchaneable. interchaneable.
a. a.
Store Store the the refri refriger gerant ant in in an an eva evacua cuated ted con contain tainer er..
(Refer to Section 3.5b) (Refer to Section 3.5b)
b. b. Unscre Unscrew w the sight the sight glass assembly glass assembly. . Spread some Spread some
sea sealin ling g com compou pound nd on on pip pipe e thre threads adsof of new new sig sight ht gla glass ss
assembly and install. assembly and install.
c. c. Leak check recei Leak check receiver sight glass per Section 3.6. ver sight glass per Section 3.6.
d. d. After After lea leak chec k checkin king g uni unit, evac t, evacuate uate and de and dehyd hydrate rate as as
outlin outlined in ed in section 3.7. section 3.7.
e. e. Add refrigera Add refrigerant charge. (Refer to section 3.8). nt charge. (Refer to section 3.8).
f. f. Check for Check for noncondensibles. noncondensibles.
4.1 4.16 6 COI COILS LS CLE CLEAN ANING ING
4. 4.16 16.1 .1 Ev Evap apora orator tor co coil il
The use of The use of recyc recycled cardboa led cardboard cartons is rd cartons is increa increasing sing
across the across the country country. . The recycled The recycled cardbo cardboard cartons ard cartons
cre create ate muc much h more more fib fiber er dus dustt dur during ingtran transpo sport rt tha than n “ne “new” w”
cartons cartons. . The fiber dust The fiber dust and particles are drawn into the and particles are drawn into the
evaporator where they lodge between the evaporator evaporator where they lodge between the evaporator
fin
fins. s. If If the coil is the coil is no not t cl clea eane ned d on a on a reg regul ular basi ar basis, s,
so some metim times es as as oft often en as as af after ter ea each ch tri trip, p, the the ac accu cumu mula latio tion n
can can be be gre great at eno enough ugh to to res restric trictt air air flow flow,, cau cause se coi coill ici icing, ng,
repetitive defrosts and loss of unit capacity. Due to the repetitive defrosts and loss of unit capacity. Due to the
“washing” action of normal defrost the fiber dust and
“washing” action of normal defrost the fiber dust and
particles may not be visible on the face of the coil but
particles may not be visible on the face of the coil but
may accumulate deep within.
may accumulate deep within.