Viking VCBB360R Service Manual page 38

Service Procedures
HFC134a service Information (continued)
•
Care must be taken to minimize moisture from
entering HFC134a system.
compressor or system open to atmosphere for
more than 10 minutes. Excessive moisture in
HFC134a system will react with compressor oil
and generate acid.
•
Compressor must be replaced when performing
low side leak repair..
•
Drier filter must always be replaced with service
drier filter. Important: Un-brazing drier filter
from tubing will drive moisture from desiccant
and into system, causing acids to form. Do not
un-braze filter drier from tubing.
service drier was installed in HFC134a system,
drier could overload due to excessive moisture.
•
HFC134a compatible copper tubing must be
used when replacing tubing.
•
Avoid system contamination by using an
evaporating oil when flaring, swagging, or
cutting refrigeration tubing.
HFC134a is alternative for CFC12.
HFC134a has an ozone depletion potential (ODP)
factor of 0.0 and a global warming potential (GWP)
factor of 0.27. HFC134a is not flammable and has
acceptable tonicity levels.
interchangeable with CFC12. there are significant
differences between HFC1134a and CFC12 which
must be considered when handling and processing
refrigerant system.
Comparison of CFC12 AND HFC134a Properties
Properties / Characteristics
Ozone Depletion Potential
Global Warming Potential
Molecular Weight
Boiling Point at 1 Atmosphere
Vapor Pressure at 77 F (25 C)
Liquid Density at 77 F (25 C)
Flammability
High-side System operating
Pressure at 65 F (18 C)
Low-side System operating
Pressure at 65 F (18 C)
Health, Safety, and Handling
Health, safety, and handling considerations for
HFC134a are virtually no different than those for
CFC12.
Do not leave
If CFC12
HFC134a is not
CFC12 HFC134a
1.0 0.0
3.2 0.27
121 102
-22 F (-30 C) -15 F (-126 C)
80 psig 82 psig
82 lb/ft 75 lb/ft
No No
HFC134a approximately 3 psig
Higher than CFC12
HFC134a approximately 2 psig
Lower than CFC12
Health, Safety, and Handling
Allowable overall exposure limit 1,000ppm
Vapor exposure to skin
Liquid exposure to skin
Vapor exposure to eye
Liquid exposure to eye
Above minimum exposure limit
Safety and handling
Spill management
Fire explosion hazards
Disposal procedures
Replacement Service Compressor
HFC134a service compressor will be charged with
ester oil and pressurized with dry nitrogen. Before
replacement compressor is installed, pull out 1 rubber
plug. A pop from pressure release should be heard.
If a pop sound is not heard, do not use compressor.
Positive pressure in compressor is vital to keep
moisture out of ester oil. Do not leave compressor
open to atmosphere for more than 10 minutes.
Compressor Testing Procedures
pressure testing or clean out of refrigeration
system. Use of oxygen, air or acetylene may result
in violent explosion.
contact with oil and acetylene will spontaneously
explode when under pressure.
Refer to Technical Date Sheet "Temperature and
Relationship Chart" for operating watts, test points,
and temperature relationship test for unit being tested
•
Temperature testing is accomplished by using 3
lead thermocouple temperature tester in specific
locations. Test point "T-1" is outlet on
evaporator coil and "T-2" inlet. Test point"T-3"
is suction tube temperature midway between
where armaflex ends and suction port of
compressor (approximately 12 inches from
compressor).
38
CFC12 HFC134a
Same
No effect Same
Can cause frostbite Same
Slight eye irritant Same
Can cause frostbite Same
Can cause Asphyxia- Same
tion, Tachycardia,
and Cardia Anthythmia
Wear appropriate skin Same
and eye protection.
Use with adequate
ventilation.
Remove or extinguish Same
ignition or combustion
sources. Evacuate or
ventilate area.
May decompose if Same
contact with flames
and heating elements
Container may explode
if heated due to
resulting pressure rise.
Combustion products
are toxic.
Recycle or reclaim Same
To avoid death or severe
personal injury, never use
oxygen, air or acetylene for
Oxygen may explode on