6-5.2 Air Flow Switch Calibration; Combination Fuel Selection; Shutting Down The Unit - Ace Heating Solutions Atlas A050 Operating And Maintenance Manual

IN SOME EXTREME CONDITIONS, SUCH AS HIGH ALTITUDES OR LOW HEATING VALUE GAS, IT MAY NOT BE
POSSIBLE TO FIRE AT THE RATED MAXIMUM WITH THE APPROPRIATE AMOUNT OF EXCESS AIR. IN THIS
CASE, REDUCE THE HIGH-FIRING RATE UNTIL THE DESIRED EXCESS AIR HAS BEEN OBTAINED AT THE
MAXIMUM FIRING RATE.

6-5.2 Air Flow Switch Calibration

The air flow switch is a safety device that insures that there is adequate air flow through the blower. The switch is preset
at the factory, in case air flow switch needs to be recalibrated:
1) Make sure the Atlas main switch is turned off.
2) Remove the Air flow switch cover.
3) Turn the flow switch adjustment screw counter clockwise until the switch is fully open.
4) Then make 4-1/2 full turns clockwise to set the switch to the appropriate setpoint.
5) Replace the air flow switch cover.

6-6 Combination Fuel Selection

On Combination Fuel Units, to switch between natural gas or propane:
1) Ensure the propane and natural gas inlet are properly and tightly connected, refer to Section 2-7, Figure 2.4.
2) If running, turn the unit off by switching the on/off switch on the control box.
3) Switch the fuel selection switch on the control box to the appropriate setting.
4) Open the manual shut off valve on the gas train for the fuel that is selected, and close the manual shut off
valve for the supply not being used.
5) Select the proper fuel for the pilot, refer to section 2-7, figure 2.5 :
a. If using a single pilot, make sure the manual valve for pilot gas is open on the natural gas supply line
regardless of main fuel selection.
b. If using a combination pilot,
i. Open the pilot manual gas valve for the appropriate fuel supply.
ii. Close the pilot manual gas valve for the fuel supply not being used.
6) Turn the unit on. Unit should turn on and resume normal operation.

6-7 Shutting Down The Unit

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