25
Heat Exchanger Removal
1. Shut water, gas, and electricity off, close valves
and relieve pressure.
2. Drain heat exchanger.
3. Loosen and remove flange bolts.
4. Remove flange and inlet/outlet pipes from the
header. Remove drain valve from rear header.
5. Remove outdoor stackless top or indoor stack top
from unit.
6. Remove jacket top, flue collector, and baffle.
7. Remove upper front jacket panel, and disconnect
wires at toggle switch.
8. Remove capillary bulb from inlet/outlet header.
9. Disconnect press switch tube from inlet/outlet
header.
10. Disconnect high limit wire from thermostat, and
pressure switch.
11. Lift heat exchanger straight up from combustion
chamber, using caution not to damage refractory.
12. Reverse above procedure to reinstall.
De-sooting Procedure
Soot can clog areas between fins and cause eventual
tube failure. Any sign of soot at the base of the burn-
ers or around the outer jacket indicates a need for
cleaning.
1. Disconnect top portion of unit. (See Heat
Exchanger Removal procedure steps 1 through
6).
2. Remove burner tray (See Burner tray Removal
procedure.)
3. Take a garden hose and wash heat exchanger,
making sure soot is removed completely from
between fins. Avoid excessive water against
refractory.
Combustion Chamber Removal
1. Remove heat exchanger (See Heat Exchanger
Removal procedure).
2. Lift up and remove front and rear refractory shield.
3. Remove refractory panels.
4. Reverse above procedure to reinstall.
CAUTION:
Soot is combustible. Exercise extreme
care. Never use a wire brush.
NOTE:
In extreme cases it may be necessary to
remove the heat exchanger completely for cleaning.
The simplest method is steam cleaning at the local
car wash. DO NOT WIRE BRUSH.
Fig. 29: Refractory Panel—Top View
Control Immersion Well
Replacement
1. Remove plumbing and top portion of unit (See
Heat Exchanger Removal procedure, steps 1
through 6).
2. Remove U.G. spring, U.G. and copper shield.
3. Collapse well tube at open end with chisel.
4. Push well up through header.
5. Insert new well and roll in place. If a roller is not
available, solder the well in place with silver sol-
der.
Unitherm Governor (U.G.)
Replacement
1. Shut water, gas and electricity off, close valves
and relieve pressure.
2. Drain heat exchanger.
3. Disconnect inlet and outlet pipes with flange from
in/ out header.
4. Grasp retainer spring from inlet side of header,
and slide thru inlet hole.
5. Remove shield.
6. Remove U.G. with seating gasket, and stainless
steel baffle (not shown).
7. Reverse above procedure to re-install.
Immersion Well
Fig. 30: Immersion Well
