SERVICE
Servicing Coolers and Condensers —
When cooler
heads and partition plates are removed, tube sheets are ex-
posed showing the ends of tubes. The 30GX,HX units use a
flooded cooler design. Water flows inside the tubes.
TUBE PLUGGING — A leaky tube can be plugged until
retubing can be done. The number of tubes plugged deter-
mines how soon the cooler must be retubed. All tubes in the
30GX and 30HX coolers and 30HX condensers can be re-
moved. Loss of unit capacity and efficiency as well as in-
creased pump power will result from plugging tubes. Failed
tubes should be replaced as soon as possible. Up to 10% of
the total number of tubes can be plugged before retubing is
necessary. Figure 14 shows an Elliot tube plug and a cross-
sectional view of a plug in place. The same components for
plugging and rolling tubes can be used for all coolers and
30HXC condensers. See Table 36.
Use extreme care when installing plugs to prevent dam-
age to the tube sheet section between the holes.
RETUBING (See Table 37) — When retubing is to be done,
obtain service of qualified personnel experienced in boiler
maintenance and repair. Most standard procedures can be fol-
lowed when retubing the 30GX and 30HX heat exchangers.
A7% crush is recommended when rolling replacement tubes
into the tubesheet. A 7% crush can be achieved by setting
the torque on the gun at 48 to 50 in.-lb (5.4 to 5.6 N-m).
The following Elliot Co. tube rolling tools are required:
B3400 Expander Assembly
B3401 Cage
B3405 Mandrel
B3408 Rolls
Place one drop of Loctite No. 675 or equivalent on top of
tube prior to rolling. This material is intended to ‘‘wick’’into
the area of the tube that is not rolled into the tube sheet, and
prevent fluid from accumulating between the tube and the
tube sheet. New tubes must also be rolled into the center
tube sheet to prevent circuit-to-circuit refrigerant leakage.
Table 36 — Plugging Components
COMPONENTS FOR PLUGGING PART NUMBER
For Tubes
Brass Pin 853103-1A*
Brass Ring 853002-640*
For Holes without Tubes
Brass Pin 853103-1A*
Brass Ring 853002-738*
Roller Extension S82-112/11
Loctite No. 675†
Locquic ‘‘N’’†
*Order directly from: Elliot Tube Company, Dayton, Ohio.
†Can be obtained locally.
Table 37 — Tube Diameters
ITEM INCHES MILLIMETERS
Tube sheet hole diameter: 0.756 19.20
Tube OD 0.750 19.05
Tube ID after rolling:
(includes expansion
due to clearance)
0.704
to
0.710
17.88
to
18.03
NOTE: Tubes replaced along heat exchanger head partitions must
be flush with tube sheet.
TIGHTENING COOLER/CONDENSER HEAD BOLTS
O-Ring Preparation — When reassembling cooler and con-
denser heads, always check the condition of the O-ring(s)
first. The O-ring should be replaced if there are any visible
signs of deterioration, cuts or damage. Apply a thin film of
grease to the O-ring before installation. This will aid in hold-
ing the O-ring into the groove while the head is installed.
Torque all bolts to the following specification and in the
sequence shown in Fig. 15.
3
⁄
4
-in. Diameter Perimeter and
Plate Bolts ........................200to225ft-lb.
(271 to 305 N-m)
SHELL BOLTS
OUTLET FOR
MOTOR COOLING
LINE CONNECTION
STEPPER MOTOR
HARNESS
MOUNTING
BRACKET
BOLTS
STEPPER MOTOR
FLOAT
ASSEMBLY
DISCHARGE GAS
BUBBLER TUBE
OUTLET TO BOTTOM
OF COOLER
LIQUID INLET
TUBE FROM
CONDENSER
Fig. 13 — 30GX,HX Cutaway View of
Economizer Assembly
PIN AND RING INSTALLED
TUBE SHEET
PIN
TUBE
RING
PIN
RING
Fig. 14 — Tube Plugging
52
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