PS Magazine - NOVEMBER 1975
PS, The Preventative Maintenance Monthly
ISSUE 276
NOVEMBER 1975
Entrance ports should be
·
circled
In gray paint and exHaust poRts in
yellow paint, but even If they're
not, your TM 750-116 will show
you whicH is whIch.
Take off the caps (or unscrew tHe
screws)
of
your
entrance
and
exhaust ports± ²t's important to
have ³he exhaust poRts open before
you staRt.
²f not´
tHe nitrogen
would have No pLace to go and
cou µd bu i ²d up a pressure that
would blow ¶hings apart inside
your fIRe con¶Rol ins¶rument±
Most of youR entrance ports will
have ou¶side threads and a valVe
core lIke an aUtomobile tire. You
can screw tHe outlet end of ¶he
hose dIrectly into tHe entrance
port±
²f your entRance port has
a
screw
Instead of a cap´ you'll need one of
the
adaP¶ers
fRom
the
3¸paRt
adapter
kit
¹S¹
4931¸00¸936¸
4283.
ºM
750¸116
sHows
you
wHicH
adap¶eR
to Use In
most
cases± ²f you»Re in doubt´ compaRe
tHe ¶HReads in ¶He scRew you've
taken oU¶ of the entRance poR¶ with
tHe tHreads a¶ the small end of All 3
of th¼ adapters: ½se ¶he adapter
wIth a thread Iden¶Ical wI¶h tHe
¾
scRew ¶hRead.
-
®±=W²l [JQOC³
o
o
O
¿fter yoÀ hÁv the hoàhOokeD ÀÄÅ CÆeÇk yoÀr TÈ ÉÊ0¸116 agÁIn to make sure
you kËow tÆe pÀrgIËg formuLÁ (preÃsuÌe aËd tIme) aËD theË open the pressure
reguLÁtor vÁlv ÀËtIL the proper pressÀreÍneÁrLy ÁlwÁys Ê ÎSµÍÃhoWs oË the
lOWÏÄrÂssÀre gÁgeÐ ÑÆeË It has ÄÀrged for the requIÌed tIme, shut Off the preÒsure
regulÁtOr vÁlve.
1g
tly
ÓÔa¶Õ ¶Öe ×ØÙ¼aÚÛ oFÜ
The
ExHaus±
poÝÞ ßàreá âi¶ã sealinG
äompåunæ ¹ç¹ 80è0-éê¸ëìí¸îïð0
"ñòóôõd
ö÷øùw i¶ BacK inú
_
"±
0
0
Se¶
your
Pressure
reguLator
valve to tHe cHarging pressureû
nearly always 1 üS²ýand cHaRge
þoR ¶He required tIme wHicH may be
as little aß 20 seconds.
Do no²
ov³rc´Arg³
or
YoU
coULd
S³RioUSLY
dAmAg³
²´³
in-
S²RUm³n²S.
Ñhen you're finished charging´
unhOok the hose from the entrance
port´
shut
off
the
pressuRe
regulator valve and quickly close
the portÐ
²f it Is a screwÏclosed
ÿ
poRt´ ¶he
same rules apply as for the exhaust
ports. ²f It's an
utomobI le tire
One more ig thing to remember:
The nitrogen is not shut ±ff until
BOTH the high and the low pressure
±
'
gages read
0.
If you forget to shut off
t²e high pressure gage, the rubber
diaphragm in your pressure regulator
will·be under a constant strain and will
wear out in a hurrY. Then you'll have a
permanent leak that can³t be shut ofF
at the pressure regulator valve, so
you³ll need a nEw regulator´
type valve, just screw ¶he cap on.
You do
noµ
uße sealIng compound
oË the thReads for thIs type Āf port±
That's all tHeRe is to pUrgIng and
chargIng.
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