Product Overview

14
103859-12 - 8/19
MPO-IQ
Installation & Service Manual
Step 2. If necessary, place your right hand under
the burner air tube to lift upward. Lift the door up
unto the built-in cast ramp/door rest (protruding
from the bottom of the front section casting - see
Figure 4A).
Step 3. Use one hand to help hold door in position
by lifting up on rear burner housing or applying
pressure directly to the door while re-installing
the securing hardware with your opposite hand.
Always install right side latching hardware (3/8"-
16 x 1-3/4" lg. tap bolt and flat washer) first, then
install left side hinge hardware (3/8"-16 x 1-3/4"
lg. tap bolt and flat washer) second. Apply
additional pressure while hand tightening the
hardware as far as possible, then release the
pressure.
NOTICE When securing burner swing door make
sure door is drawn-in equally on both sides.
Step 4. Use a hand wrench to tighten door hardware
and always start with the right side cap screw
first. Use an alternating tightening method from
right side tap bolt to left side tap bolt to tighten
door equally until sealed without applying
excessive torque. Never tighten left side flange
bolt first or tighten either piece of hardware 100%
without using the alternating tightening method
described above.
Failure to follow the prescribed procedure could
cause thread damage to casting or a leak in the
door seal. If left side tap bolt is tightened before
right side tap bolt, right side of door can not be
drawn-in to provide an air tight seal, as shown in
Figure 4C. Applying excessive torque will only
cause thread damage.
E. INSPECT SWING DOOR INSULATION AND ROPE
GASKET.
1. Open burner swing door using procedure previously
outlined in Paragraph D of this section.
2. Inspect fiberglass rope located on the swing door.
The rope must be evenly distributed around the
perimeter of the door groove and cannot bunch or
overhang. There must not be a gap where the two
ends of the rope meet. Repair or replace if the rope
is damaged or if there is a gap between the ends.
3. Inspect burner swing door insulation for damage
and proper type, refer to Figure 4D.
a. By design, cast bars on front section between
the combustion chamber and between the left
and right side 2
nd
and 3
rd
pass flueway should
make an impression in door insulation to seal
the chambers.
b. By design, door insulation on model MPO-IQ231B
will have two (2) by-pass pockets cast into the
insulation centered on the bar between the
combustion chamber and 3
rd
pass flueways.
On models MPO-IQ84B thru MPO-IQ189B these
pockets should not be present. If insulation is
damaged or not of proper type regarding pockets,
it must be replaced.
4. Do not close and secure door at this time, proceed
to Field Assembly Details, Paragraph F.
F. FIELD ASSEMBLY OF BOILER
Open miscellaneous parts carton and remove contents.
Identify the components using the illustrations (Figures
5 thru 9) throughout the assembly sequence outlined
below as it applies to your installation.
1. Install return injector piping and relief valve, refer
to Figure 5.
Figure 4C: Top View - Burner Swing Door
Fully Closed but
Not Properly Secured or Sealed
2 Packaged Boiler Assembly - Trim & Controls (continued)