Table of Contents
Advertisement
I-.l
CHECKING
OPERATIOT\f
- (A' Moders)
Th e f ol l o w i n g g en e ra l i nfo rma tio n e x-
p l a i n s s ev e ra l m e th od fo r ch e ckin g op e r -
at i on o f t h e r e f ri g er ati o n system. Th is
i n for m at i o n a p p l i es to a l l syste ms cove r e d
i n t h i s m a n u a l .
The c o r re ct o p e ra ti o n o f a re fri g e r atio n
sy s t e m i s d e p e n de n t u p o n the p r o pe r
f u n c t i o n i n g o f e a ch o f th e p a rts co mp r isin g
the system. lf the system does not operate
pr op e rl y (l o n g ru n pe ri o d s, w a rmer tha n
no rm a l t e m p e ra t ure s), th e tr ou b l e m a y b e
c a us ed by o n e o f t he fo ll o wi n g con ditio n s.
RESTRICTED CAPILLARY TUBE
The o pe n i n g o f a ca pi l l ar y tu b e is a b o u t
t h e s a m e d i a m e t er a s th e p e ri od a t th e
e n d o f t hi s s e n t e n ce . T hi s sho u l d i nd ica te
t h at i t d o e s n ' t t a ke mu ch to re str ict th is
t u b e. l t s ho u l d a l so tel l yo u to use ca r e
w h en an y s e r vi ce p ro ce du re s invo lve
m o v i n g o r t o u c h i n g t h e c a p i l l a r y t u b e . A
v e r y s l i g h t ki n k ca n cau se a co mple te r e -
s t ri c t i on o f t h e t u b e .
R e s t ri c t i o n s o f t h e ca p i ll a ry tu b e ma y b e
ca u se d by : ( 1 ) m o i stu re free ze -u p, ( 2) to r -
e i gn p a rt i cl e s l o d g e d in th e tu b e , o r ( 3 ) a
b e n d o r k i n k .
l f t he c a p i l l a ry t u b e is re stri cte d , th er e will
b e a n o ti c e a b l e l ack o f fr ost o n al l o f th e
coo l i n g su rf a ce s; t he co mpre sso r m a y op -
e r a t e f o r a sh o rt p eri o d o f ti me and th e n
cyc l e o n th e o ve rl oa d . Be ca u se so m e m o -
d e l s ca n h o l d t h e e n ti re ch a rg e in the
co nd e n s e r , t h e c o mp re sso r ma y ru n co n-
ti n uo u s l y a n d d e f i ni te va cu u m wi l l b e no -
ti c e d i n th e l o w sid e . Wh e n mo istur e
f re ez e -u p ca u se s a re str icti o n, i t u su ally
oc c u rs a t t h e o u t l e t e n d of the cap illa r y
t u be . No r ma l l y, a fro st b ui l d -u p c a n b e
d e te ct e d i n t h i s are a , b u t in su latio n
w r a pp e d a ro u n d t h e tu bi n g ma y con ce a l
o r li mi t t he a m o u n t o f fr ost a ccum u la tio n .
Expose t he dischar ge end of the capi llar y
and apply heat at this point . lf t her e is
e nough head pr essur e, and if the re-
st riction is caused by m oistur e f reez e- up,
y o u w i l l b e a b l e t o h e a r a g u r g l i n g n o i s e
as the heat releases the ref rigerant
t h r o u g h t h e t u b i n g .
It is possible t hat this m oistur e w ill be ab-
sorbed by the drier and rem edy t he tr ou-
ble. H owever, if t he f reeze-up r ecur s , you
must replace t he drier.
A k i n k i n t h e c a p i l l a r y t u b e w i l l r e v e a l
about the same symptom as a moi sture
freeze-up except f or t he accum ulation of
frost. Check the ent ir e length of t he capil-
lary t ube and, if possible, st raighten the
kink to r elieve the r est rictions. Chec k the
u nit oper ation t o see if you have helped
the sit uat ion. lf t he tr ouble per si sts , r e-
place the defective part.
lf t he f reeze-up condition does not ex is t
a nd t here is not a kink, you can ass ume
that a for eign part icle is causing the r e-
st rict ions - - t he only r emedy in t his c as e i s
to r eplace t he restr ict ed part .
PARTIAL RESTRICTION IN LOW
SIDE TUBING
B ent t ubing, foreign mat ter , or moistur e i n
the system may cause a par tial restri ction
i n t h e l o w s i d e t u b i n g . T h i s i s u s u a l l y i n -
dicated by fr ost-f ree t ubing betw een the
r estriction and the capillary tube and by
f rost-covered tubing between the re-
st rict ion and t he suct ion line. The re-
st rict ion act s like a second capillary tube,
increasing the pressure ahead of it
( war ming) and decreasing t he press ur e
beyond it (cooling) . To conf ir m the ex is t-
e n c e o f a r e s t r i c t i o n i n t h e l o w s i d e t u b i n g ,
perf orm operat ional pr essur e check s .
3-5
Advertisement
Table of Contents
