Section V Unit START-UP, Setting Burner | Wing Enterprises IOMWDF-1

SECTION V - UNIT START-UP

Close or replace all doors and service panels.

Turn main disconnect switch off. Verify the incoming line voltage matches the unit nameplate rating. If the voltage is over ±10% of nameplate rating or phase voltage unbalance is over 2%, notify the contractor or power company.

Turn Heat OFF/ON switch to the OFF position. Turn main disconnect switch on. Turn Fan OFF/ON switch to the ON position. Damper opens. Blower fan turns on.

Turn Fan OFF/ON switch to OFF position and check sup- ply blower for proper rotation.

NOTE: To change rotation of the blower, simply interchange any two (2) of the line leads of the motor starter for three (3) phase motors. Refer to motor nameplate for reversing single (1) phase motors.

Turn Fan OFF/ON switch to the ON position. Check for proper blower rpm. Check that all motor amp draws do not exceed nameplate ratings, and the overload relay is set to the motor nameplate amperage.

Check dampers for proper operation. Be sure they operate freely, and the linkage does not bind.

Make sure all manual gas shut-off valves are in the closed position.

Turn Heat OFF/ON switch to the ON position. Blower fan will run.

Turn Fan and Heat OFF/ON switches to OFF position.

Setting Burner

NOTE: To adjust gas pressure on supply lines where a regulator has been installed (to reduce the inlet pressure to 1/2 PSIG or less), remove dust cap of main gas regulator and turn adjusting screw clockwise to increase pressure, or counter-clockwise to decrease pressure.

Set all thermostats to call for heat. Set inlet ductstat (if applicable) above outside air temperature.

Connect a DC microammeter between the SENSE terminal and the flame rod sensing wire.

Turn Fan and Heat OFF/ON switches to ON position.

Open inlet manual gas shut-off valve slowly. Reset high and (if applicable) low gas pressure switches. Check main gas line for leaks using soap solution.

Unit will run for 5 seconds before ignition trial.

NOTE: 3 OR 4 TRIALS MAY BE NEEDED TO PURGE AIR FROM GAS LINE.

UnitedTechnologies Electronic Controls Spark Ignitor

Watch microammeter carefully. The reading should be at least 5.0 microamps. If the reading is too low, slowly turn the low-fire adjustment on the modulating valve in or out until satisfactory readings are obtained. When adjusting low fire, there should be a continuous flame along the entire burner length without any blowout spots.

Refer to Maxitrol Valve Adjustment instructions in Section IX for setting high and low fire gas pressure settings.

When the flame is adjusted, shut the unit off by turning the Fan and Heat switches to OFF.

Setting Main Flame

Install manometer at test port on the last tee of the burner manifold or modulating valve.

Slowly open all manual gas shut-off valves.

Restart unit. After main gas valves open and burner lights check gas lines for leaks.

Adjust high gas pressure reading (from manometer) to match firing rate shown on unit nameplate.

Adjust the high and low fire setting according to the Maxitrol Valve Adjustment instructions in Section IX. The high fire setting must not exceed the pressure stated on the rating plate.

When adjusting low fire, there should be a continuous flame along the entire burner length without any blow out spots.

Main flame is now set. Recheck the microamp signal on the ignition control throughout the full burner input range. Re- check low fire setting. Cycle unit 2 or 3 times to insure good ignition.

Safety Controls Check

A.High Temperature Limit and Firestats – These limit controls are not adjustable and are checked by the factory. Reset the red button(s) to be sure they are ready for operation. Contact the factory if these switch- es fail to reset.

B.Ignition Control - Operate unit in Heat mode. After flame has been established, close last manual gas valve before main burner.The ignition control must trip out within 15 seconds. Reset the ignition control by turning the HEAT switch to the OFF position.