Vav Systems With Ddp Supply Fan; Exhaust Airflow Measurement (Optional With All Units) - Trane IntelliPak Installation, Operation And Maintenance Manual

Unit Start Up
amperage at the supply fan contactor 1K16 & 1K15
(additional contactor for 90 thru 75Ton units). If the
amperage exceeds the motor nameplate value, the
static pressure is less than design and the airflow is too
high. If the amperage is below the motor nameplate
value, static pressure may be too high and CFM may be
too low.To determine the actual CFM (± 5%);
a. Measure the actual fan RPM
b. Calculate theTheoretical BHP
Actual Motor Amps
X Motor HP
Motor Nameplate Amps
c. Plot this data onto the appropriate Fan Performance
Curve in Figure 60, p.
intersect, read straight down to the CFM line.
Use this data to assist in calculating a new fan drive if the
CFM is not at design specifications.
An alternate method with less accuracy is to measure the
static pressure drop across the evaporator coil.This can be
accomplished by;
i. drilling a small hole through the unit casing on
each side of the coil.
Note: Coil damage can occur if care is not taken when
drilling holes in this area.
ii. Measure the difference between the pressures at
both locations.
iii. Plot this value onto the appropriate pressure
drop curve in Figure
(Component Static Pressure Drops) to assist in
calculating a new fan drive if the CFM is not at
design specifications.
iv. Plug the holes after the proper CFM has been
established.
9. Press the STOP key at the Human Interface Module in
the unit control panel to stop the fan operation.

VAV Systems with DDP Supply Fan

Supply Airflow Measurement for DDP Fans
Piezometer rings are available on units with DDP fans to
measure supply airflow. Piezometer rings can interface
with customer-supplied airflow monitoring systems using
the K-factors and equation shown below. Connections are
located one the fan side of each assembly.
Table 46. Piezometer Ring K-Factors
Nominal Capacity K-factor
20, 25 Ton 2454
30 Ton 3010
40 Ton 3701
50, 55 Ton 4620
60 Ton 6020
70, 75 Ton 7402
104
106. Where the two points
79. Use the data in Table 47
Note: If assuming standard air density, obtain the airflow
using: CFM = K*SQRT(DP) where DP is the
differential pressure (Inches w.c.)
Exhaust Airflow Measurement (Optional
with all Units)
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.
1. Close the disconnect switch or circuit protector switch
that provides the supply power to the unit's terminal
block 1TB1 or the unit mounted disconnect switch
1S14.
HIGH VOLTAGE IS PRESENT AT TERMINAL BLOCK
1TB1 OR UNIT DISCONNECT SWITCH 1S14.
2. Turn the 115 volt control circuit switch 1S1 and the 24
volt control circuit switch 1S70 to the "On" position.
3. Open the Human Interface access door, located in the
unit control panel, and press the SERVICE MODE key to
display the first service screen. Refer to the latest
edition of the appropriate programming manual for CV
or VAV applications for the SERVICETEST screens and
programming instructions.
4. Use Table 42, p. 96 to program the following system
components for operation by scrolling through the
displays;
– Exhaust Fan
– Exhaust Dampers (100% Open, if applicable)
– Outside Air dampers (100% Open)
– Variable Frequency Drive (100%, if applicable)
– RTM Occ/Unocc Output (Default)
5. Once the configuration for the components is
complete, press the NEXT key until the LCD displays
the "Start test in __Sec. " screen. Press the + key to
designate the delay before the test is to start.This
service test will begin after theTEST START key is
pressed and the delay designated in this step has
elapsed. Press the ENTER key to confirm this choice.
6. Press theTEST START key to start the test. Remember
that the delay designated in step 5 must elapse before
the fans will begin to operate.
RT-SVX36K-EN