Lennox HARMONY II, Руководство по установке, Страница: 10 / 30

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505023M 04/06
3. Determine heating PIAB and total heating air CFM
delivered during a heating call
Calculate these to-
tals using the formulas and example in Table 7. The ex-
ample uses the following assumptions:
D
Zone 1 Jumper 30%
D
Zone 2 Jumper 50%
D
Zone 3 Jumper 40%
D
Zone 4 Jumper OFF
D
Zones calling for heat 1 & 3
D
Heat reduction jumper 20
D Maximum CFM 2220
D
Minimum CFM 720
Table 7
Determine Total Heating CFM Delivered
Formulas:
Total PIAB =
(Sum of Calling Zones
Jumper Positions)
+
(# of Zones Calling − 1)
3
Heating PIAB =
Total PIAB x (1 − Heating air reduction setting)
Total Heating CFM =
Heating PIAB x (CFM Max − Min) + (Min CFM)
1st− Find Total PIAB:
[Jumpers 30% +0% +40% +0%] .30 +.00 +.40 +.00 . . . . . .
+ [2 zones −1]/3 +. 33 . . . . . . . . . . . . . . . . . . . .
TOTAL 1.03 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower cannot support 103%; uses 100%
= 1 . . .
2nd− Find Heating PIAB:
b
[Total PIAB] 1 . . . . . . . . . . . . . . . . . . . . . . .
x [1−Heating air reduction setting] x 1−.2 . . . . .
TOTAL = .8 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3rd− Find Heating Total CFM:
b
[Heating PIAB] .8 . . . . . . . . . . . . . . . . . . . . .
x [CFM (Max) 2220 − (Min) 720] x 1500 . . . . . . .
+ [Min CFM] + 720 . . . . . . . . . . . . . . . . . . . . . . .
TOTAL = 1920 CFM . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Determine total air delivered during a continuous
blower call
Calculate these totals using the formu-
las and example (Table 8) which uses the same as-
sumptions as table 7, except with zones 1, 2 and 3 call-
ing for cooling, and with 25% air reduction:
Table 8
Determine Total Continuous CFM Delivered
Formulas:
Total PIAB =
(Sum of Calling Zones
Jumper Positions)
+
(# of Zones Calling − 1)
3
Continuous Air PIAB =
Total PIAB x (1 − Cont. air reduction setting)
Total Continuous CFM =
Cont. Air PIAB x (CFM Max −
Min)
+ (Min CFM)
1st− Find Total PIAB:
[Jumpers 30% +50% +40% +0%] .30 +.50 +.40 +.00 . . . . .
+ [3 zones −1]/3 +. 66 . . . . . . . . . . . . . . . . . . . .
TOTAL 1.86 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower cannot support 186%; uses 100%
= 1 . . .
2nd− Find Continuous Air PIAB:
b
[Total PIAB] 1 . . . . . . . . . . . . . . . . . . . . . . .
x [1−Continuous air reduction setting] 1−.25 . .
TOTAL = .75 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3nd− Find Total Continuous CFM:
b
[Continuous Air PIAB] .75 . . . . . . . . . . . . . .
x [CFM (Max) 2220 − (Min) 720] x 1500 . . . . . . .
+ [Min CFM] + 720 . . . . . . . . . . . . . . . . . . . . . . .
TOTAL = 1845 CFM . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IMPORTANT
If any changes are made to the blower speed selec-
tions on the SureLight
®
or BDC3 boards, the zone
control PIAB calculations must be performed again
to ensure proper airflow.