MAXIM

AXIAL FLOW GAS BURNER START-UP (continued)

PRESSURE PLATE

Set up and Tolerances

Figure 17-3

13.Connect a test meter to the control for reading the flame response signal.

NOTE: Some controls read the flame signal in micro amps and some in volts DC. The TFM or MC120 series control has two terminals marked for reading volts DC. The S89 control uses a micro amp signal for measuring flame strength. For this control, a meter must be hooked in series with the flame rod wire. Disconnect the leadwire at the S89 sensor terminal. Connect the positive lead of the meter to the quick-connect sensor terminal on the S89 and the negative lead to the free end of the sensor leadwire.

14.Be sure the tank is filled with water. Once the burner is reassembled, two devices to read pressure, preferably U-tube manometers, will be needed to read gas pressures. Connect one to read the inlet pressure of the burner. This is the pressure measured before all components in the gas train. The manometer must stay connected throughout the testing as the inlet pressure

must be monitored during the firing of the burner. Record static pressure; it must not exceed 14" W.C. Pressures above this could cause damage to the diaphragm in the gas valve or pressure regulator.

15.Burners with pilot; inputs over 400,000 Btu/h (See wiring diagram.)

16.Connect a manometer to the manifold test port at the shutoff valve closest to the burner. Turn off the main gas shutoff valve. Set the air shutter as shown on the tag attached to gas train. This may not be the exact setting you end up with, but it is a good starting point. Turn the unit on using the rocker switch on the side of the control enclosure assembly. If the operating control switches are closed, the burner blower should come on and pre-purge begin.

If nothing happens, check the control to be sure it is not in the tripped position and reset it by pushing the flame safeguard reset button. The burner should pre-purge for no longer than thirty seconds.

PV500-17 05-2000

8

Section 17