Carrier 30GTN Service And Troubleshooting Manual page 54

Tube Plugging — A leaky tube can be plugged until retub-
ing can be done. The number of tubes plugged determines
how soon cooler must be retubed. Tubes plugged in the fol-
lowing 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. Ther-
mistor T2 is used in the freeze protection algorithm for the
controller. If several tubes require plugging, check with your
local Carrier representative to find out how number and lo-
cation can affect unit capacity.
Figure 24 shows an Elliott tube plug and a cross-sectional
view of a plug in place.
Use extreme care when installing plugs to prevent dam-
age to the tube sheet section between the holes.
Retubing (See Table 29) — 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 10HB coolers. An 8% crush is rec-
ommended when rolling replacement tubes into the tube
sheet. 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.
SIZES 040-050
SIZES 080,090*
*And associated modular units (see Table 1).
Fig. 23 — Typical Tube Sheets, Cover Off (Non-Removable Tubes)
SIZES 060,070
SIZES 100,110*
54
Fig. 24 — Eliott Tube Plug
Table 29 — Plugs
COMPONENTS FOR
PLUGGING
For Tubes
Brass Pin
Brass Ring
For HoleswithoutTubes
Brass Pin
Brass Ring
Loctite
Locquic
*Order directly from: Elliott Tube Company,
Dayton, Ohio
†Can be obtained locally.
Tube information follows:
• Tube sheet hole diameter . . . . . . . . . . . . 0.631
• Tube OD . . . . . . . . . . . . . . . . . . . . . . . . . 0.625
• Tube ID after rolling . . . . . . . . . . . . . . . 0.581
(includes expansion due
to clearance)
NOTE: Tubes next to gasket webs must be flush with tube
sheet (both ends).
SIZES 130,150*
SIZE 210*
PART NUMBER
853103-500*
853002-570*
853103-1*
853002-631*
No. 675†
''N''†
in. mm
16.03
15.87
14.76
to to
0.588 14.94
SIZES 170,190*