AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 83)

HE-
111 − DISASSEMBLY AND REASSEMBLY
Rev B Mar 2013 9-3
7. Mark the edge of the heat exchanger lower head assembly flanges (8) in order to indicate their
correct relative positions for reassembly.
8. Remove nuts (9) and studs (10) from the heat exchanger lower head assembly flanges.
9. Using a hoist or block and tackle attached to the lifting lugs (11) on the heat exchanger upper head
assembly, CAREFULLY lift the upper head assembly (12) and shell (13) STRAIGHT UP off the heat
exchanger U-bend tubing assembly. AVOID SCRAPING THE SHELL AGAINST THE TUBING (14).
10. Clean and inspect the inside of the shell and the U-bend tubing assembly for obvious damage.
11. If a leak in the tubing has been detected (see steps 1 through 4) and it has been determined that the
leak is in the outside wall of one or more of the double-wall tubes, the leak may be found either by a
thorough inspection or as follows:
a. Connect a source of cold water to the leak detection port (15).
b. Turn the water on and locate the source of the leak or leaks.
c. You may either reassemble the heat exchanger and return it in its entirety to AERCO for
repair, or remove the U-bend tubing assembly and return only that assembly to AERCO for
repair. See step 14 for equipment return information.
12. To disassemble the U-bend tubing assembly (14) from the heat exchanger, remove nuts (9) and
studs (10) and lift the assembly off the manifold and skid assembly (16).
13. If for any reason it is necessary to remove the heat exchanger upper head assembly (12) from the
shell (13):
a. Remove the thermocouple (17) from its location in the heat exchanger upper head assembly.
b. Remove all connecting wiring, if any, from the heat exchanger upper head assembly.
c. Remove all piping and wiring to the relief valve (1) and water Solenoid Valve (2).
d. Remove the nuts (18), studs (19), and lifting lugs (11).
e. Lift the upper head assembly off the shell.
14. If the heat exchanger or any of its assemblies are to be returned to the AERCO factory for repair,
consult AERCO or your nearest AERCO sales representative for instructions.
CAUTION
Inspect and replace any lugs, nuts and studs that show signs of
corrosion with new properly rated hardware.
9.4 REASSEMBLING THE HEAT EXCHANGER
1. BEFORE REASSEMBLING, CLEAN ALL GASKET SURFACES THOROUGHLY, using a wire brush
or emery cloth, if necessary. ALWAYS USE NEW GASKETS in a reassembly.
2. If the heat exchanger U-bend tubing assembly (14) must be reassembled onto the manifold and skid
assembly (16), then proceed as follows:
a. Place a lower tubesheet release gasket (20), a lower tubesheet gasket (21), and a second lower
tubesheet release gasket (ALL NEW) onto the manifold flange (22).
b. Lower the U-bend tubing assembly over the four studs in the manifold flange and onto the
manifold gaskets, making sure the bottom flange of the U-bend assembly seats onto the locating
pin in the top surface of the manifold flange, and that the U-bend assembly is lined up for
insertion of the studs through the flanges.