35
7.
Remove the heat exchanger as follows:
a.
Carefully remove the insulation from the top
(front and rear) and sides of the heat
exchanger. These will be reused on the new
assembly.
b.
Loosen the Dresser nut on the bottom of the
heat exchanger connecting the 1-1/2" pipe
nipple to the 90
°
Dresser elbow.
c.
Remove the 12 bolts connecting the heat
exchanger to the economizer (two in front, two
in back and four on each side.)
d.
Lift heat exchanger off the economizer and set
it aside (it may be necessary to pry the two
assemblies apart to break the gasket seal.)
LEAK CHECK [AM-300]
1.
Pressure test the heat exchanger with water. Keep
pressurized for at least an hour or until leak is
spotted. The leak may be small and take a while
before it becomes noticeable. If necessary to replace
heat exchanger, refer to replacement parts list and
follow packaged instructions.
2.
Pressure test the economizer. If necessary to
replace economizer, refer to replacement part list
and follow packaged instructions.
REASSEMBLING AM-300 BOILER
1.
Attach heat exchanger to economizer as follows:
a.
If re-using the economizer, remove the old
gasket used to seal the two assemblies from the
economizer. The top of the economizer may
have some accumulated rust and debris. Scrape
or brush the surfaces and remove all loose dirt.
If rusted, spray with zinc cold galvanized
compound.
NOTICE: Extreme care should be taken in
positioning gasket (step 1b) and in placing the
heat exchanger (step 1f) to assure the gasket
remains in position. A displaced gasket will
result in a flue gas leak and noisy operation.
b.
Position new gasket on the economizer as
follows:
(1) Starting on the front (thickest plate or
thickest section of front plate) lay the gasket on
the edge against the retaining plate. Lay the
gasket on all four top surfaces of the economizer
forming the corners so that the gasket is always
on the plate. When the gasket over-laps itself
miter cut at 45
°
to form an overlapping butt joint
(see fig. 8).
(2) Use high temperature silicone RTV to hold
the butt together and at occasional spots
between the top edge of the economizer and the
gasket to hold the gasket on the plate edge.
(3) Lay an approximately 4" piece of the 1/4"
square braided gasket next to and overlapping
the butt joint. Use high temperature silicone
RTV to hold in place.
c.
Place Dresser elbow on the pipe stub of the
economizer. Snug the nut and leave elbow
pointing up.
d.
Connect the 1-1/2 TOE pipe nipple into bottom
of the heat exchanger.
e.
Place the “Dresser” nut and gasket components
on the pipe nipple. Secure these parts against
the bottom head of the heat exchanger to
prevent them from dropping off during handling.
f.
Pick up the heat exchanger and place it on the
economizer. The pipe (step 1d) must fit into
Dresser elbow on the economizer and the bolt
holes in the bottom head of the heat exchanger
must line up with the corresponding holes on the
economizer bracket.
CAUTION: The heat exchanger must be
accurately placed in position to assure the
gasket is not displaced. Do not slide the heat
exchanger on the gasket to align the holes. If
shifting is required pick up the heat exchanger,
check that the gasket is in position and repeat
step (1f). Use of a “guide pin” in a hole on each
side of the heat exchanger can help placement
with the holes on the economizer bracket. Visu-
ally check that the gasket is in place before
proceeding.
g.
Assemble the 1-1/2" nut to the Dresser elbow.
h.
Locate the 12 bolts, nuts and washers, and snug
up all nuts. Torque the nuts to 10 ft.-lbs. Then
retorque all the nuts in 5 ft.-lb. increments to
25 ft-lbs. in a staggered pattern. Tighten nuts
on Dresser coupling.
i.
Clean the top surface of the Combustion
Chamber and the “O” ring groove. Position the
“O” ring in the groove. Place the Combustion
Chamber Inlet on the Combustion Chamber
and secure with the (4) four Allen-head screws.
j.
Wrap and secure the insulation from the old
boiler around the heat exchanger.
k.
Replace the spark plug - use an anti-seize
compound on the threads.
2.
Install the Air Cushion Chamber (ACC)
a.
Observe location of, and remove old gasket
from bottom flange of the ACC and install a new
gasket.
b.
Locate the ACC on the heat exchanger by
aligning the holes in the ACC flange with the
holes in the heat exchanger. Install the 90
°
angle clip, bolts, washers and nuts and tighten.
c.
Seal openings at the outside bottom corners of
the ACC with silicone caulk for an air tight seal.
