Energy Tech Laboratories LB360, LB480, LB300, LB600 Hole Location for Pressure Drop Reading

035-18496-000-C-1102

To check the supply air CFM after the initial balanc- ing has been completed:

1.Drill two (2) 5/16-inch holes in the side panel as shown in Figure 24.

2.Insert at least 8 inches of 1/4 inch tubing into each of these holes for sufficient penetration into the airflow on both sides of the evaporator coil.

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 pres- sure drop across the wet coil under field conditions would be inaccurate. To assure a dry coil, the refrigerant system should be de-activated while the test is being run.

4.Knowing the pressure drop across a dry coil, the actual CFM through the unit can be determined from the curves shown in Figures 25-28.

If the CFM is above or below the specified value, 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.

Failure to properly adjust the total system air quantity can result in extensive blower dam- age.

After readings have been obtained, remove the tubes and seal up the drilled holes in the side panel. 5/16 inch dot plugs (P/N 029-12880) are available through normal York parts ordering procedures.

25"

7"	5/16"
	HOLE

EVAPORATOR

COIL

22"

5/16"

HOLE

14"

FILTERS

COIL SECTION

FIGURE 25 - HOLE LOCATION FOR PRESSURE DROP READING

Unitary Products Group 25