Raypak AVIA 264A Installation And Operation Manual page 40

Orifice Removal
1. Locate and close the external manual shutoff valve.
2. Loosen the external gas union.
3. Locate and remove jacket top.
4. Locate and remove the four (4) bolts & nuts holding
the gas orifice in place. See Figure 65.
5. Carefully remove the gas orifice and do not misplace
the O-rings attached to the flanges.
6. Inspect and/or replace the orifice with the correct
size.
BRACKET
O-RING
Figure 65. Orifice Location
Gas and Orifice Selection
The gas orifice and the air orifice MUST match to attain
the correct air/fuel ratio. The orifices are matched when
the number of pockets on the side of the gas orifice is the
same as the number of notches on the edge of the air
orifice. The orifice selection is based on elevation, not on
the fuel used. See Table R.
The gas orifice is located on the gas train, between the gas
valve and the combustion blower. The air orifice is located
on the inlet side of the combustion blower.
NOTE: Gas orifices for propane gas have a black oxide
finish.
Figure 66. Gas Orifice
40
GAS ORIFICE
Pockets /
Model
Notches
1 264
2 404
1 264
2 404
Table R.
Igniter Removal
.
1. Remove top cover.
2. Disconnect spark cable from igniter.
3. Use M10 socket, remove the two nuts holding the
igniter.
4. Carefully remove igniter and gasket.
5. When replacing igniter, be sure to add a new gasket
when installing igniter.
.15 +/- .01
Figure 67.
Burner Removal
1. See "Combustion Blower Removal" steps below.
Must remove blower to reach the burner.
2. Once the blower is removed. Use an M10 socket to
remove (16) nuts holding down the burner.
3. Be sure to install a new gasket before installing the
burner.
Gas Type Finish
Natural None
Propane Black
Orifice Usage
Igniter