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HEAT EXCHANGER REMOVAL
1. Shut water, gas and electricity off, close valves
and relieve pressure, remove relief valve. Re-
move side inspection panels.
2. Remove top holding screws.
3. Remove draft diverter, lift and remove top and flue
collector on stack-type models. Remove inspec-
tion panels.
4. Loosen bolts and disconnect flange nuts on inlet/
outlet header, loosen union(s) at gas pipe and slide
boiler away from piping until studs clear the
header.
5. Remove combustion chamber clips at the four
corners of the heat exchanger.
6. Lift heat exchanger straight up using caution not to
damage refractory.
7. Reverse above procedure to reinstall.
CONTROL IMMERSION WELL REPLACEMENT
1. Shut water off to heater and drain heat exchanger.
2. Remove jacket top panel.
3. Remove old control well with bushing and sleeve,
with 7/8" wrench or socket.
4. Slip "O" ring gasket over control well and install in
header.
"O" RING GASKET
WELL ASSEMBLY
Fig. # 8101.0
UNITHERM GOVERNOR (U.G.) REPLACEMENT
1. Shut water, gas and electricity off, close valves and
relieve pressure.
2. Drain heat exchanger.
3. Remove retainer plug located under outlet pipe
connection.
4. Remove spring and replace old U.G. with a new
U.G.
5. Reverse above procedure to re-install.
Fig. # 8128.0
GASKET
U.G.
RETAINER PLUG
SPRING
FIig. # 8071.0
To test the operation of the Unitherm Governor,
place in hot water (over 110 °F) and watch for move-
ment against spring. If there is no movement, replace
unit.
TUBE CLEANING PROCEDURE (Typical)
Establish a regular inspection schedule, frequency
depending on local water condition and severity of
service. Do not let the tubes clog up solidly. Clean out
deposits over 1/16" in thickness.
The heater must be cleaned from the rear as
shown. It is preferable, however, to remove the heat
exchanger and the in/out header for better visibility
through the tubes and to be sure the ground-up lime
dust does not get into the system.
Note that you do not remove the top panel or the
heat exchanger, generally.
After reaming, mount the wire brush in place of the
auger and clean out debris remaining in the tubes.
Another method is to remove the heat exchanger,
ream tubes and immerse heat exchanger in non-
inhibited de-scale solvent.