Direct-Drive Supply Fan Speed Adjustment; System Airflow Measurements; Vav And Cv Systems With Ddp Supply; Fan And Motorized Impeller Relief Fan - Trane IntelliPak 3 with Symbio 800 Installation, Operation And Maintenance Manual

Startup the Unit
Direct-Drive Supply Fan Speed
Adjustment
Units equipped with a DDP Supply Fan do not use belt/
sheave arrangements to adjust fan speed.
This adjustment (if required) is made through the Fan VFD
by setting the supply fan Min/Max frequency at each supply
fan VFD using Table 26, p.
Table 26. RPM and Hz ranges for DDP supply fan
speed adjustments
Fan Speed (RPM)
Max Min
2400 888
2300 851
2200 814
2100 777
2000 740
1900 703
1800 666
1700 629
1600 592
1500 555
1400 518
1300 481
Table 27. Piezo airflow calculation
Fan dia,
Unit in F
20,25,30
16.5 1518.6
40,50,55
18.2 1821.9
20,25,30,40-
,50,55
20 2185.8
20,25,30,60-
,70,75
22.2 2713.9
40,50,55
24.5 3285
60,70,75
27 3397.6
Notes:
1. Measure pressure from inlet side of fan to piezo tap at
the cone throat.
2. Fan inlet will be the high pressure side.
3. dP can be up to 25 in h 0.
2
4. Coefficients are for one fan. For two fans double result
or F and C1 values.
5. For standard density of 0.075 lb/ft^3, Supply Fan CFM =
CFM = F * √ dP
6. For non-standard density, Supply Fan CFM = CFM = C1
* A * √ (dP / ρ), where dP is the piezo pressure
differential and rho is the actual air density.
For relief fans, check the nameplate model number on the
fan to determine the K-factor, see table below.
64
64.
VFD Frequency Range (Hz)
Max Min
83 31
79 29
76 28
72 27
69 26
66 24
62 23
59 22
83 31
79 29
74 27
68 25
C1 A
753.06 0.55
692.03 0.72
692.03 0.87
692.03 1.07
692.03 1.3
692.03 1.58
Table 26. RPM and Hz ranges for DDP supply fan
speed adjustments (continued)
Fan Speed (RPM)
Max Min
1200 444
1100 407
1000 370
Note: Maximum operating speed cannot exceed fan wheel
mechanical limit.

System Airflow Measurements

VAV and CV Systems with DDP Supply

Fan and Motorized Impeller Relief Fan

(optional)

Supply and Relief Airflow Measurement
Piezometer pressure taps are available to measure supply
and relief airflow. Piezometer pressure taps can interface
with customer-supplied airflow monitoring systems using
the F or K-factors and equation shown in the tables below.
Attach one end of the pressure differential gauge to a
connection in the fan cone throat, and the second to the fan
inlet plate to read pressure immediately upstream of the
fan.
VFD Frequency Range (Hz)
Max Min
63 23
58 21
53 20
RT-SVX080A-EN