55
Tube Plugging
— A leaky tube can be plugged until retubing
can be done. The number of tubes plugged determines how
soon cooler must be retubed. Tubes plugged in the following
locations will affect the performance of the unit: Any tube in
the area, particularly the tube that thermistor T2 is adjacent to,
will affect unit reliability and performance. Thermistor T2 is
used in the freeze protection algorithm for the controller. If sev-
eral tubes require plugging, check with your local Carrier rep-
resentative to find out how number and location can affect unit
capacity.
Figure 26 shows an Elliott tube plug and a cross-sectional
view of a plug in place.
Retubing (See Table 31)
— When retubing is to be done, ob-
tain service of qualified personnel experienced in boiler main-
tenance and repair. Most standard procedures can be followed
when retubing the 10HB coolers. An 8% crush is recommend-
ed when rolling replacement tubes into the tubesheet. An 8%
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 Elliott 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.
Table 31 — Plugs
*Order directly from: Elliott Tube Company, Dayton, Ohio.
†Can be obtained locally.
Tube information follows:
NOTE: Tubes next to gasket webs must be flush with tube
sheet (both ends).
Tightening Cooler Head Bolts
Gasket Preparation — When reassembling cooler heads,
always use new gaskets. Gaskets are neoprene-based and are
brushed with a light film of compressor oil. Do not soak gasket
or gasket deterioration will result. Use new gaskets within
30 minutes to prevent deterioration. Reassemble cooler nozzle
end or plain end cover of the cooler with the gaskets. Torque
all cooler bolts to the following specification and sequence:
5
/
8
-in. Diameter Perimeter Bolts . . . . . . . . . . . . 150 to 170 ft-lb
(201 to 228 N-m)
1
/
2
-in. Diameter Flange Bolts . . . . . . . . . . . . . . . . 70 to 90 ft-lb
(94 to 121 N-m)
1. Install all bolts finger tight.
2. Bolt tightening sequence is outlined in Fig. 27. Follow
the numbering or lettering sequence so that pressure is
evenly applied to gasket.
Use extreme care when installing plugs to prevent damage
to the tube sheet section between the holes.
COMPONENTS FOR
PLUGGING
PART NUMBER
For Tubes
Brass Pin
853103-500*
Brass Ring
853002-570*
For Holes without Tubes
Brass Pin
853103-1*
Brass Ring
853002-631*
Loctite
No. 675†
Locquic
“N”†
in. mm
• Tube sheet hole diameter . . . . . . . . . . 0.631 16.03
• Tube OD . . . . . . . . . . . . . . . . . . . . . . 0.625 15.87
• Tube ID after rolling. . . . . . . . . . . . . . . 0.581 14.76
(includes expansion due to to
to clearance) 0.588 14.94
Fig. 26 — Elliott Tube Plug
SIZES 060,070
SIZES 080,090*
SIZES 100,110*
SIZES 130,150*
SIZES 170,190*
SIZE 210*
*And associated modular units (see Tables 1A and 1B).
Fig. 25 — Typical Tube Sheets, Cover Off (Non-Removable Tubes)
SIZES 040-050
