Slant/Fin CB-45 Installation And Operating Instructions Manual page 29

Air and Gas Orifice Plates with Convertible Gas Orifice
Figure 24. Convertible Gas Orifice Installation
Note: This revised design features a gas orifice plate which contains both the natural gas and the propane gas orifice
hole. Whether this design is implemented on any particular Concept boiler depends on when the boiler was
manufactured. Follow these instructions only if the boiler is equipped with the design features shown here.
BOILER
MODEL
PROPANE
ORIFICE
GAS ORIFICE PLATE ORIENTATION
1. The gas orifice plate contains both the natural gas
orifice hole and the propane gas orifice hole, to
provide for a fast and simple conversion to either
gas use.
2. Each gas orifice hole on the plate has an I.D. tab
located adjacent to it. The I.D. tab specifies the boiler
model and type of gas for each orifice. The larger
hole in the plate is always the natural gas orifice hole,
and is adjacent to the I.D. tab that is stamped "NAT".
The smaller hole in the plate is always the propane
gas orifice hold, and is adjacent to the I.D. tab that is
stamped "PROP".
3. When installed properly, the I.D. tab that is stamped
for the type of gas being utilized must face outward
over the straight flange in the gas manifold, so that it
is clearly in view.
GAS ORIFICE PLATE CONVERSION
1. Turn off power and gas supply to boiler.
2. Remove boiler jacket front cover by turning the four
slotted fasteners one quarter turn.
3. Remove boiler jacket right side cover by removing
the four sheet metal screws.
4. Remove the four nuts on the gas manifold angle
flange.
5. Pull out the four screws on the gas manifold straight
flange far enough to remove the gas orifice plate.
6. Place the gas orifice plate in the position specified in
the orientation instructions for the type of gas being
GAS TYPE
NATURAL GAS
I.D.
ORIFICE.
GAS TYPE
I.D.
BOILER
MODEL
GAS ORIFICE
I.D. TAB
SCREWS
STRAIGHT
GAS
FLANGE
VALVE
AIR ORIFICE
PLATE WITH
GASKETS
BURNER
ENCLOSURE
AIR ORIFICE
ADAPTER
O-RING
GAS
O-RING
ORIFICE
PLATE
utilized. To convert from one type of gas to the other
the plate should be rotated 180°. The I.D. tab for the
gas being utilized must face outward over the straight
flange in the gas manifold so that it is clearly in view.
7. Reposition the four screws through the flanges and
orifice plate and tighten the four nuts onto the
screws. Make sure the nuts are tightened evenly and
with sufficient force to prevent loosening or leakage.
8. Replace boiler jacket covers removed for this
procedure.
9. The appropriate self-adhesive gas conversion label
supplied with these instructions must be positioned
adjacent to the boiler rating plate, if the gas being
utilized differs from the gas specified on the rating
plate.
10. Power and gas supply can be turned back on to
operate boiler.
AIR ORIFICE PLATE
1. The air orifice plate for each boiler model is the same
for both natural and propane gas — no conversion is
necessary.
2. Each model's air orifice plate has an I.D. tab which
protrudes from the side of the boiler, behind the
boiler jacket right side cover. The I.D. tab is stamped
for the model of each boiler it is to be installed on.
IMPORTANT: Reorificing for altitude change is NOT
necessary on this Concept boiler.
AIR ORIFICE
I.D. TAB
(BOILER MODEL)
NUTS
STUDS
NUTS
ANGLE
FLANGE
2