HEATER AND AIR CONDITIONING 1A-22
P O O R L Y LO C A T E D PO W ER E L E M E N T B U LB
N orm al P re s s u re .
P o o r Cooling.
Check for Defective V a lv e
The follow in g procedu re must be follow ed to determ ine
i f a malfunction is due to a d efective expansion valve.
1. Check to determ in e i f the system w ill m eet the p e r
form ance test as outlined p revio u sly.
If the expan
sion va lve is d e fe c tiv e , the low p ressu re readings
(P O A o r evap orator p ressu re) w ill be above s p e c ifi
cation.
2. The lo s s o f system p erform an ce is not as evident
when the c o m p resso r head p ressu re is below 200 PSI.
T h e re fo re , it may be n ecessa ry to in crease the s y s
tem head p ressu re by p a rtia lly blocking the conden
s e r.
Disconnect the blow er lead w ire and repeat the
"P e r fo r m a n c e check" to determ ine i f the evaporator
p ressu re can be obtained.
3. The system w ill also indicate a low r e frig e ra n t
charge by bubbles occu rrin g in the sight glass.
System s equipped with a P O A V a lve req u ire the
follow in g additional test to determ ine if the de
ficien cy is the expansion va lve.
4. Rem ove the expansion va lve bulb fro m the evaporator
outlet pipe, and the connector on the b low er r e s is to r.
P la c e the blow er on " lo w ." W ith the engine op erat
ing at 2,000 rpm , ob serve the P O A gage p ressu re.
5. In sert the expansion va lve bulb in a cup o f ic e . This
should resu lt in the P O A p ressu re being reduced
to approxim ately 30 P .S .I. If the p ressu re does not
reduce to this le v e l, the P O A va lve is d efective. If
the p ressu re fa lls con siderably below 30 P .S .I., the
expansion valve is d efective.
ENGINE IDLE COMPENSATOR
T h is additional aid to p reven t stallin g during prolonged
hot weather p eriod s is included with a ll a ir conditioned
v eh icles.
The idle com pensator is a th erm ostatically
con trolled a ir bleed which supplies additional a ir to the
id le m ixture.
On V -8 engines, with fa cto ry in stalled a ir
conditioning system s, the com pensator is located within
the ca rb u retor and is a ccessib le when the engine a ir
clea n er is rem oved.
On a ll other v eh icles the compen
sator is threaded into a m anifold fittin g below the c a r
bu retor.
A ll com pensators a re fa cto ry set and a re non-
adjustable.
A malfunctioning unit should be replaced.
NOTE:
If engine idle is e r r a tic , hold the idle
com pensator
valve closed with a pen cil o r
wooden dowel while adjusting the id le m ixture
s c re w (s ). N e v e r attempt to bend the bim etal
strip o r attempt any valve adjustment.
EVACUATING AND CHARGING PROCEDURES
AIR C O N D IT IO N IN G SYSTEM CAPACITY
R e frig e ra n t
Charge
O il Charge
F our-Season System
3 lbs. 4 oz.
10 oz. 525 V is c o s ity
Roof-M ounted
4 lbs. 8 oz.
13 oz. 525 V is c o s ity
GM C h evrolet
3 lbs. 4 oz.
10 oz. 525 V isco sity
PURGING THE SYSTEM
In replacing any of the a ir conditioning components the
system must be com p letely purged o r drained o f r e
frig e ra n t.
The purpose is to lo w e r the p ressu re inside
the system so that a component part can be sa fely r e
moved.
1. W ith engine stopped, in stall high and low pressu re
lin es o f Charging Station gauge set to the p rop er
high and low p ressu re gauge fittin gs.
(See "In s ta ll
ing Charging Station to Check System O peration .")
NOTE:
B efo re in stalling lin es, be sure that a ll
four con trols on the gauge set a re closed.
2. Disconnect vacuum line at Charging Station vacuum
pump and lay end o f line on a clean rag on the flo o r.
3. C rack open high (2) and low (1) p ressu re control
va lv e s , and allow re frig e ra n t to purge fro m system .
CA UTIO N:
Do not open va lv e s too much o r
co m p resso r o il may be discharged with the r e
frig e ra n t.
O il lo s s can be e a s ily detected on
rag at disch arge line.
EVA CU A TIN G A N D C H A R G IN G THE SYSTEM
G E N E R A L N O TE :
In a ll evacuating p ro c e
dures shown below, the sp ecification o f 26-28
inches o f M ercu ry vacuum is used. Th ese f i g
u res are only attainable at o r near Sea L e v e l
E levation.
F o r each 1000 fe e t above sea le v e l
where this operation is being p erfo rm ed , the
specification s should be lo w ered by 1 inch. E x
am ple:
at 5000 ft. elevation, only 21 to 23
inches o f vacuum can norm ally be obtained.
W henever the a ir conditioning system is open fo r any
reason, it should not be put into operation again until it
has been evacuated to rem ove a ir and m oisture which
may have entered the system .
The follow in g p rocedu res a re based on the use o f the
J-8393 Charging Station.
Filling Charging Cylinder
1. Open va lve on bottom of charging cylin d er allowing
re frig e ra n t to enter cylin der.
2. B leed cylin d er valve on top (behind control panel) as
requ ired to allow re frig e ra n t to enter. When r e f r ig
erant reach es d esired le v e l (see " A i r Conditioning
System C apacity"), close va lve at bottom o f cylin der
and be certain bleed va lve is closed secu rely.
NOTE:
It w ill be n ecessary to close bleed
va lve p erio d ic a lly to allow boilin g to subside to
check le v e l in sight glass.
Evacuating and Charging System
1. Install charging station and purge system as noted
CHEVROLET TRUCK SERVICE MANUAL
Содержание 10 Series 1970
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Страница 38: ...HEATER AND AIR CONDITIONING 1A 8 CHEVROLET TRUCK SERVICE MANUAL...
Страница 57: ...HEATER AND AIR CONDITIONING 1A 27 Fig 35 Compressor M ountings CHEVROLET TRUCK SERVICE MANUAL...
Страница 75: ...HEATER AND AIR CONDITIONING 1A 45 Fig 65 R oof M ounted System W iring Diagram CHEVROLET TRUCK SERVICE MANUAL...
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Страница 101: ...BODY IB 23 s A ADJUSTER SCREW AND LEVER ASSY Fig 5 9 Exploded V iew o f Level Ride Seat CHEVROLET TRUCK SERVICE MANUAL...
Страница 137: ...BODY IB 59 VIEW IN DIRECTION OF ARROW A Fig 137 A u x ilia ry Seat CHEVROLET TRUCK SERVICE MANUAL...
Страница 142: ...CHEVROLET TRUCK SERVICE MANUAL Fig 5 10 30 Series Truck Frame FRAME 2 4...
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Страница 228: ...REAR SUSPENSION AND DRIVE LINE 4 52 I Fig 88 Forward Rear A xle Assembly Exploded V iew CHEVROLET TRUCK SERVICE MANUAL...
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Страница 383: ...ENGINE FUEL 6M 19 F ig I t Engine Fuel S p ecial Tools CHEVROLET TRUCK SERVICE MANUAL...
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Страница 432: ...Fig 1 C lu tch Linkage Except P 2 0 4 0 Series...
Страница 433: ...CLUTCHES AND TRANSMISSIONS 7 3 Fig 2 C lutch Linkage Step Van P 20 40 Series CHEVROLET TRUCK SERVICE MANUAL...
Страница 506: ...FUEL TANK AND EXHAUST SYSTEMS 8 8 Fig 10 Vent Lines Cab M ounted Tanks CHEVROLET TRUCK SERVICE MANUAL...
Страница 528: ...Fig 31 T yp ica l Power Steering Hose Routings...
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Страница 566: ...ELECTRICAL BODY AND CHASSIS 12 4 Fig 3 Front Lighting Assemblies CHEVROLET TRUCK SERVICE MANUAL...
Страница 567: ...ELECTRICAL BODY AND CHASSIS 12 5 Fig 4 C learance and Id e n tific a tio n Lamps CHEVROLET TRUCK SERVICE MANUAL...
Страница 568: ...ELECTRICAL BODY AND CHASSIS 12 6 Fig 5 Rear Lighting Composite CHEVROLET TRUCK SERVICE MANUAL...
Страница 597: ...ELECTRICAL BODY AND CHASSIS 12 35 Fig 37 Engine Com partm ent CE M E60 CHEVROLET TRUCK SERVICE MANUAL...
Страница 598: ...ELECTRICAL BODY AND CHASSIS 12 36 TO FRAME i f Fig 38 Engine Com partm ent C D 50 CHEVROLET TRUCK SERVICE MANUAL...
Страница 608: ...ELECTRICAL BODY AND CHASSIS 12 46 Fig 48 Instrument Panel C A40 CE CS ME50 Exc 02 CHEVROLET TRUCK SERVICE MANUAL...
Страница 610: ...ELECTRICAL BODY AND CHASSIS 12 48 Fig 50 Instrument Panel CE M E60 03 13 CHEVROLET TRUCK SERVICE MANUAL...
Страница 614: ...ELECTRICAL BODY AND CHASSIS 12 52 Fig 54 Instrument Panel SA40 50 CHEVROLET TRUCK SERVICE MANUAL...
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Страница 649: ...SPECIFICATIONS 9 ENGINE SECTION 6 CHEVROLET TRUCK SERVICE MANUAL...
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