York D2EB installation instructions Checking Supply Air CFM, DEB Coil Delta P vs Airflow

174065-YIM-A-0206

Checking Supply Air CFM

To check the supply air CFM after the initial balancing has been completed:

1.Remove the two ¼ inch dot plugs in the duct panel.

2.Insert at least 8 inches of ¼ inch tubing into each of these holes for sufficient penetration into the airflow on both sides of the indoor coil.

3.Using an inclined manometer, determine the pressure drop across the dry evaporator coil. Since the moisture on an evapo- rator coil may vary greatly, measuring the pressure drop across a wet coil under field conditions would be inaccurate. To ensure

a dry coil, the compressors should be deactivated 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 curve in Coil Delta P vs. Supply Air CFM figure.

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

After readings have been obtained, remove the tubes and rein- stall the two ¼ inch plugs removed in Step 1.

NOTE: De-energize the compressors before taking any test measurements to ensure a dry indoor coil.

DEB Coil Delta P vs Airflow

	0.4	DEB018		DEB024					DEB048
	0.35
	0.3
	0.25
P										DEB018
										DEB048
Delta	0.2
										DEB024
										DEB030, 36, & 42
Coil
	0.15									DEB060
ID
	0.1
	0.05									DEB060
										DEB030-42
	0
	400	600	800	1000	1200	1400	1600	1800	2000	2200
	-0.05

Airflow (CFM)

Unitary Products Group 7