28 PNEG-308 Purafire
9. Start-Up
Figure 9A
7. Disconnect the manometer and replace the 1/8" plug.
8. Open the door to the burner side of the heater. Remove the 1/8" plug from the manifold side of the
valve. Connect manometer as in step 2, then repeat step 3 and 4 when the solenoid engages to
ignite the gas valve the reading on the gauge should read a maximum of 11" W.C. for LPG, and
3.5" W.C. for NG. This reading is the manifold pressure for the unit and is the most important
reading for actual heater output. To adjust manifold pressure, remove the gas valve cover and
slotted brass screw that covers the regulator. (See Figure 9A.) Turn the nylon regulator screw
clockwise to increase pressure and counterclockwise to decrease pressure. When pressure is set,
replace all covers and repeat steps 6 and 7.
9. Turn the supply gas ON.
NOTE: Each gas valve is set at the factory for NG or LPG use. To convert a unit already in field service
to a different gas, the proper conversion kit must be purchased. The manifold pressure is set
at the factory on an individual heater basis. This setting must be checked after
field installation.