York K4EU120A50A Typical Motor Mounting Assembly, Hole Locations Pressure Drop Readings

3.Using an inclined manometer, determine the pressure drop across a dry evaporator coil. Since the moisture on an evaporator coil may vary greatly, measuring the pressure drop across a wet coil under field conditions would be inac- curate. To assure a dry coil, the refrigerant system should be de-energized while the test is being run.

4.Knowing the pressure drop across a dry coil, the actual air- flow through the unit can be determined from the curve in Figure 7.

If the airflow is above or below the specified valve, the supply air motor pulley may have to be readjusted. After one hour of operation, check the belt and pulleys for tightness and align- ment.

WARNING: Failure to properly adjust the total system air quan- tity can result in extensive blower damage.

550.39-N4YI

After readings have been obtained, remove the tubes and seal up the drilled holes in the side panel with 516" (8mm) dia. dot plugs (P/N 029-13880) available through normal parts ordering procedure.

TABLE 3 - SUPPLY AIR BLOWER MOTOR PULLEY ADJUSTMENT

	BLOWER DRIVE RANGE (RPM)
TURNS OPEN*	KEU090	KEU120
	650 -850	700 - 910
5	650	700
4	690	740
3	730	780
2	770	830
1	810	870
0	850	910

* Pulleys can be adjusted in half-turn increments.

FIG 6 - TYPICAL MOTOR MOUNTING ASSEMBLY

FIG. 7 - PRESSURE DROP ACROSS A DRY EVAPORATOR COIL VS SUPPLY AIR CFM

DIMENSIONS (in./mm)

A	B	C	D
3 / 76	3 / 76	14 / 356	12 / 305

NOTE: DE-ENERGIZE THE REFRIGERANT SYSTEM BEF- ORE TAKING ANY TEST MEASUREMENTS TO AS- SURE A DRY EVAPORATOR COIL.

FIG. 8 - HOLE LOCATIONS (PRESSURE DROP READINGS)

Unitary Products Group 7