Refrigeration & Air Conditioning Technology, 8e - xvi

✔ Do not breathe excessive amounts of the adhesive used for plastic
fittings.
The interconnecting piping should be inspected for loose
The crankcase of a compressor should not be cold to the
✔ Only use chemicals that give off dangerous fumes in well-ventilated areas.
insulation and oil spots (indicating a leak) and to ensure the
touch below the oil level. This is a sure sign that liquid refrigerant
✔ Follow all manufacturers' instructions when using soldering and
pipe is secure. Some piping is in trenches in the floor. A trench
is in the refrigerant oil on some
systems, not necessarily in great
xvi
Preface
brazing materials.
that is full of water because of a plugged floor drain will hurt
amounts, but enough to cause diluted refrigerant oil. Diluted
the capacity of the equipment because the insulation value
refrigerant oil causes marginal lubrication and bearing wear.
of the suction-line insulation is not as great when wet. A heat
Fan motors may be inspected for bearing wear. Again,
Green Awareness
exchange between the liquid lines and suction lines or the
do not mistake end play for bearing wear. Some fan motors
ground and suction lines will occur. The pipe trenches should
require lubrication at the correct intervals.
As previously mentioned, global warming stemming
be kept as clean as practical.
A general cleaning of the equipment room at regular interfrom the uncontrolled rate of greenhouse gas
vals emiswill ensure the technician good working
when
Theconditions
correct size,
layout, and installation of tubing, piping, and
sions is a major global environmental issue.a Buildings
failure occurs.
fittings helps to keep a refrigeration or air-conditioning system

7.1 purpose of Tubing
and piping

are important users of energy and materials and so
operating properly and efficiently and prevents refrigerant loss.
are a major source of the greenhouse gases that are
the by-products of energy and materials use. At the
time of this writing, there are approximately 5 million
too warm, it should be stopped and allowed to cool. If the comThis whistle is evidence of an internal leak from the high side
commercial buildings and 125 million housing
units
pressor has internal motor-temperature safety controls, do not
to the low side.
in the United States. Surprisingly, almost every one of
operate it when the control is trying to stop the compressor.●● ●
If the compressor has service valves, a closed-loop test
their mechanical systems is obsolete. Discussions relatcan be performed on the compressor using the methods we
ing to the green awareness movement (for example,
have explained while it is in the system. NOTE: Make sure no
lowering energy costs, reducing operating and main29.21 SERVICE TECHNICIAN CALLS
air is drawn into the system while it is in a vacuum. ●●●●● SAFETY
tenance costs, increasing productivity, and decreasing
PRECAUTION: The compressor temperature should be monitored
In addition to the six problems typically encountered in
the amount of pollution generated) are highlighted in
at any time these tests are being conducted. If the compressor gets
refrigeration systems, many more problems are not so typigreen throughout the text.

HVAC GOLDEN RULES
When making a service call to a business:
●●

●●
●●

●●

●●

●●

●●

●●

●●

Never park your truck or van in a space reserved for
customers.
Look professional and be professional.
Before starting troubleshooting procedures, get all the
information you can regarding the problem.
Be extremely careful not to scratch tile floors or to soil
carpeting with your tools or by moving equipment.
Be sure to practice good sanitary and hygiene habits
when working in a food preparation area.
Keep your tools and equipment out of the customers'
and employees' way if the equipment you are servicing is
located in a normal traffic pattern.
Be prepared with the correct tools and ensure that
they are in good condition.
Always clean up after you have finished. Try to provide
a little extra service by cleaning filters, oiling motors,
or providing some other service that will impress the
customer.
Always discuss the results of your service call with the
owner or representative of the company. Try to persuade the owner to call if there are any questions as a
result of the service call.

cal. The following service situations will help you understand troubleshooting. Most of these service situations have
already been described, although not as actual troubleshooting procedures. Sometimes the symptoms do not
describe the problem and a wrong diagnosis is made. Do
not draw any conclusion until the whole system has been
examined. Become a system doctor. Examine the system
and say, "This needs further examination," and then do it.
Refrigeration systems often cool large amounts of food so
they are slow to respond. The temperature may drop very
slowly on a hot or warm pulldown.

SERVICE CALL 1
A customer calls and complains that the compressor for a
medium-temperature walk-in cooler with a remote condensing unit is short cycling and not cooling correctly. The evaporator has two fans, and one is burned. The unit is short cycling
on the low-pressure control because there is not enough load
on the coil.
On the way to the job the technician goes over the possible problems. This is where it helps to have some familiarity
with the setup. The technician remembers that the unit has a
low-pressure control, a high-pressure control, a thermostat,
an overload, and an oil safety control. Defrost is accomplished
with an off cycle using the air in the refrigerated space with
the fans running. By the process of elimination the technician
decides that the thermostat and the oil safety control are not
at fault. The thermostat has a 10°F differential, and the cooler

HVAC Golden Rules
Golden Rules for the refrigeration and air-conditioning
technician give advice and practical hints for developing good customer relations. These "golden rules"
appear in appropriate units.
tion

Conditions
Operating
and Typical
ubleshooting

Unit 29 Tro

ial Refrigera
for Commerc

RIGE
FOR REF
ENANCE

R AT I O N

793

ays
cannot alw
technician
Grease
ularly. The
evaporator.
cleaned reg
d
the
an
at
d
g
the
cte
kin
of
ing
inspe
by loo
utine clean
coil is dirty
built and
the coil. Ro
SAFETY
uipment is
tell when a
the core of
may
coil clean.
r
in
ckaged eq
the
ne
Pa
be
ep
ow
y
T.
ke
ma
EN
food is
or dirt
cause the
EQUIPM
will usually
ounds where
intenance be breakdown occurs.
PACKAGED
once a year
cleaning comp
evaporator
minimum ma
. Cover the fan
ly approved
d
tem
it until a
on
an
sys
e
of
y
d
Us
re
an
N:
ate
designed for
ca
ing
t water
PRECAUTIO
ently lubric
n that takes
r before clean
th
ing to preven
are perman
off the powe
be the perso
replaced wi
s when clean
fan motors
present. Turn
e they are
l connection ●● ●
Most of the
at which tim
d all electrica
an
it,
s
m.
qu
d and
tor
the
y
o
ale
mo
the
int
se
g
til
ually
ndensers
will run un
nt from gettin
unit are us
and deterge
keep the co
ricated at
evaporator
ould be lub
educated to
new ones.
sh
tors in the
ck the cony
be
mo
blo
the
ld
e
to
t,
ou
motor.
Th
as
sh
If no
se
r
rked on the
The owners
lubricated.
entory so clo
r, the owne
are often ma
bearing
permanently
t to stack inv
ch-in coole
ervals, which
tions
d look for
int
ec
an
ed
dir
clean and no When the unit is a rea
nt
s
nd
me
er'
me
recom
for align
w.
. Most small
manufactur
be
fan blade
motor shaft
denser airflo
to follow the
ide should
s for
Observe the be found by lifting the
cautioned
mistake thi
e on the ins
t
lin
no
d
y
loa
Do
should be
ma
e
y.
wear. This
aring wear.
le end pla
the box. Th
considerab
discover be
rigerated
tribution.
in loading
to
ve
ref
dis
ha
aft
ch
air
rs
sh
co
ea
er
to
be me
mo
prop
lift the
amine
m dirt and
actions
observed for
r should ex
ar. You must
r weight fro
r noises or
or manage
bearing we
any peculia
y also gathe
ould
of
ma
sh
The owner
t
de
are
tha
r
aw
bla
lly
ete
The fan
tly and be
ld be visua
a thermom
race.
unit frequen
should have
section shou
and
rise in tempe
out of balan
x. Each box
evaporator
ment. Any
t
the power
ge
tha
the
off
r
na
in
ut
ge
ma
sh
from the bo
g
na
d,
ma
y by
heater
All wirin
ed or fraye
ed each da
ld alert the
rs and any
s of
be monitor
If it is crack
e itself shou
necessary los
defrost heate e warm during
inspected.
es not revers
prevent un
forget the
ture that do
. This can
the drain lin
it. Do not
ng
e
ep
rri
lac
ke
cu
rep
to
oc
is
ed
a problem
should be
may be us
tapes that
equipment
foods.
all package
perishable
er.
l service for
cold weath
The electrica

PREVENT

T
IVE MAIN

Preventive Maintenance
Preventive Maintenance procedures are
included in many units and relate specifically to
the equipment presented in that unit. Technicians can provide some routine preventive
maintenance service when on other types of
service calls as well as when on strictly maintenance calls. The preventive maintenance
procedures provide valuable information for the
new or aspiring technician and homeowner, as
well as for those technicians with experience.



Refrigeration & Air Conditioning Technology, 8e

Table of Contents for the Digital Edition of Refrigeration & Air Conditioning Technology, 8e

Contents
Refrigeration & Air Conditioning Technology, 8e - Cover1
Refrigeration & Air Conditioning Technology, 8e - Cover2
Refrigeration & Air Conditioning Technology, 8e - i
Refrigeration & Air Conditioning Technology, 8e - ii
Refrigeration & Air Conditioning Technology, 8e - iii
Refrigeration & Air Conditioning Technology, 8e - Contents
Refrigeration & Air Conditioning Technology, 8e - v
Refrigeration & Air Conditioning Technology, 8e - vi
Refrigeration & Air Conditioning Technology, 8e - vii
Refrigeration & Air Conditioning Technology, 8e - viii
Refrigeration & Air Conditioning Technology, 8e - ix
Refrigeration & Air Conditioning Technology, 8e - x
Refrigeration & Air Conditioning Technology, 8e - xi
Refrigeration & Air Conditioning Technology, 8e - xii
Refrigeration & Air Conditioning Technology, 8e - xiii
Refrigeration & Air Conditioning Technology, 8e - xiv
Refrigeration & Air Conditioning Technology, 8e - xv
Refrigeration & Air Conditioning Technology, 8e - xvi
Refrigeration & Air Conditioning Technology, 8e - xvii
Refrigeration & Air Conditioning Technology, 8e - xviii
Refrigeration & Air Conditioning Technology, 8e - xix
Refrigeration & Air Conditioning Technology, 8e - xx
Refrigeration & Air Conditioning Technology, 8e - xxi
Refrigeration & Air Conditioning Technology, 8e - xxii
Refrigeration & Air Conditioning Technology, 8e - xxiii
Refrigeration & Air Conditioning Technology, 8e - xxiv
Refrigeration & Air Conditioning Technology, 8e - 1
Refrigeration & Air Conditioning Technology, 8e - 2
Refrigeration & Air Conditioning Technology, 8e - 3
Refrigeration & Air Conditioning Technology, 8e - 4
Refrigeration & Air Conditioning Technology, 8e - 5
Refrigeration & Air Conditioning Technology, 8e - 6
Refrigeration & Air Conditioning Technology, 8e - 7
Refrigeration & Air Conditioning Technology, 8e - 8
Refrigeration & Air Conditioning Technology, 8e - 9
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Refrigeration & Air Conditioning Technology, 8e - 11
Refrigeration & Air Conditioning Technology, 8e - 12
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Refrigeration & Air Conditioning Technology, 8e - 30
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Refrigeration & Air Conditioning Technology, 8e - 40
Refrigeration & Air Conditioning Technology, 8e - 41
Refrigeration & Air Conditioning Technology, 8e - 42
Refrigeration & Air Conditioning Technology, 8e - 43
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Refrigeration & Air Conditioning Technology, 8e - 45
Refrigeration & Air Conditioning Technology, 8e - 46
Refrigeration & Air Conditioning Technology, 8e - 47
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Refrigeration & Air Conditioning Technology, 8e - 50
Refrigeration & Air Conditioning Technology, 8e - 51
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Refrigeration & Air Conditioning Technology, 8e - 53
Refrigeration & Air Conditioning Technology, 8e - 54
Refrigeration & Air Conditioning Technology, 8e - 55
Refrigeration & Air Conditioning Technology, 8e - 56
Refrigeration & Air Conditioning Technology, 8e - 57
Refrigeration & Air Conditioning Technology, 8e - 58
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Refrigeration & Air Conditioning Technology, 8e - 63
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Refrigeration & Air Conditioning Technology, 8e - 66
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Refrigeration & Air Conditioning Technology, 8e - 70
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Refrigeration & Air Conditioning Technology, 8e - 81
Refrigeration & Air Conditioning Technology, 8e - 82
Refrigeration & Air Conditioning Technology, 8e - 83
Refrigeration & Air Conditioning Technology, 8e - Cover4
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