107272-UIM-B-1105

APPLYING FILTER PRESSURE DROP TO

 

Multiply percentage by airflow difference to obtain airflow reduction.

DETERMINE SYSTEM AIRFLOW

 

 

(0.5) X (-65) = -32.5

 

 

 

 

 

 

Example: For a 84,000 BTUH (38.06 kW) furnace with 1 return open-

Subtract airflow reduction value to airflow @ 0.10 w.c. (125 Pa) to

ings and operating on high-speed blower, it is found that total system

obtain actual airflow @ 0.30 wc (144 Pa) ESP.

 

 

 

static is 0.30” w.c. (0.075 kPa). To determine the system airflow, com-

1050 - 32.5 = 1017.5

 

 

 

 

 

 

plete the following steps:

 

 

 

 

 

 

 

 

 

 

 

 

FINAL PROCEDURE

 

 

 

 

 

Obtain the airflow values at 0.10 w.c. (125 Pa) & 0.20 w.c. (150 Pa)

 

 

 

 

 

ESP.

 

 

 

Install Furnace Doors

 

 

 

 

 

Airflow @ 0.10”: 1175 CFM (60.17 m3/min)

 

 

Install the lower door first by sliding the bottom of the door down until

Airflow @ 0.20”: 1110 CFM (57.62 m3/min)

 

 

the tabs on the casing base engage the slots in the bottom door end

Subtract the airflow @ 0.10 w.c. (125 Pa) from the airflow @ 0.20 w.c.

cap. Then push the top of the lower door in until the door clips snap into

place. Install the upper door in a similar manner, first engaging the slots

(150 Pa) to obtain airflow difference.

 

 

1175 - 1110 = -65 CFM (2.55 m3/min)

 

 

in the top of the upper door on the tabs on the casing top. Then snap

 

 

the bottom of the upper door into place against the casing.

 

Subtract the total system static from 0.10 w.c. (125 Pa) and divide this

 

Finish and Trim

 

 

 

 

 

 

difference by the difference in ESP values in the table, 0.20

w.c.

 

 

 

 

 

 

(150 Pa) - 0.10 w.c. (125 Pa), to obtain a percentage.

 

 

Alcove and Closet Installations may now be finished and trimmed as

(0.30 - 0.10) / (0.20 - 0.10) = 0.5

 

 

necessary.

 

 

 

 

 

 

 

TABLE 14: Blower Performance CFM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BLOWER PERFORMANCE CFM - DFAA066

 

 

 

 

 

 

 

FACTORY EQUIPPED WITH STANDARD BLOWERS AND FILTERS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXTERNAL STATIC PRESSURE, INCHES WC (kPa)

 

 

 

 

 

 

 

 

 

 

 

 

 

Blower Speed

BTU/H (kW)

CFM

0.1 (0.025)

0.2 (0.050)

0.3 (0.075)

0.4 (0.099)

0.5 (0.124)

Input / Output

(m3 / min)

 

 

 

 

 

 

 

 

 

 

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

 

Single Speed - No Coil

66(19.34) / 53(15.55)

1050(29.73)

1175

33.3

1110

31.4

1050

29.7

1000

28.3

950

26.9

Single Speed - With Dry Coil

66(19.34) / 53(15.55)

1050(29.73)

1125

31.9

1070

30.3

1020

28.9

960

27.2

910

25.8

 

 

BLOWER PERFORMANCE CFM - DFAA084

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXTERNAL STATIC PRESSURE, INCHES WC (kPa)

 

 

 

 

 

 

 

 

 

 

 

 

 

Blower Speed

BTU/H (kW)

CFM

0.1 (0.025)

0.2 (0.050)

0.3 (0.075)

0.4 (0.099)

0.5 (0.124)

Input / Output

(m3 / min)

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

 

Single Speed - No Coil

84(24.62) / 67(19.63)

1250(35.39)

1370

38.8

1305

37.0

1245

35.3

1175

33.3

1100

31.1

Single Speed - With Dry Coil

84(24.62) / 67(19.63)

1250(35.39)

1265

35.8

1195

33.8

1120

31.7

1045

29.6

1015

28.7

 

 

BLOWER PERFORMANCE CFM - DFAH066

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXTERNAL STATIC PRESSURE, INCHES WC (kPa)

 

 

 

 

 

 

 

 

 

 

 

 

 

Blower Speed

BTU/H (kW)

CFM

0.1 (0.025)

0.2 (0.050)

0.3 (0.075)

0.4 (0.099)

0.5 (0.124)

Input / Output

(m3 / min)

 

 

 

 

 

 

 

 

 

 

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

 

Single Speed - No Coil

66(19.34) / 53(15.55

1050(29.73)

1155

32.7

1111

31.5

1055

29.9

995

28.2

920

26.1

 

 

BLOWER PERFORMANCE CFM - DFAH084

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXTERNAL STATIC PRESSURE, INCHES WC (kPa)

 

 

 

 

 

 

 

 

 

Blower Speed

BTU/H (kW)

CFM

0.1 (0.025)

0.2 (0.050)

0.3 (0.075)

0.4 (0.099)

0.5 (0.124)

Input / Output

(m3 / min)

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

cfm

cm/m

 

Single Speed - No Coil

84(24.62) / 67(19.63)

1250(35.39)

1127

31.9

1062

30.1

1005

28.5

952

27.0

887

25.1

NOTES:

 

 

 

 

 

 

 

 

 

 

 

 

1.Airflow expressed in standard cubic feet per minute (cfm) and in cubic meters per minute (cm/m)

2.Return air is through louvered filter door only.

3.Motor voltage at 115V

Unitary Products Group

25

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York DFAA, DFAH Applying Filter Pressure Drop to, Determine System Airflow, Final Procedure, Install Furnace Doors