KMC CONTROLS TRF-5901C-AFMS TrueFit Airflow Measurement System User Guide

KMC CONTROLS TRF-5901C-AFMS TrueFit Airflow Measurement System

Specifications

• Model: TRF5901CAFMS, TRF9311CAFMS, TRF9311CE-AFMS
• Applications: RTU, AHU, unit ventilator
• Inputs: TRF5901CAFMS – 10 total (8 universal), TRF9311CAFMS/TRF9311CE-AFMS – 1 air pressure sensor and 8 standard
• Outputs: TRF5901CAFMS – 10 total (8 universal), TRF9311CAFMS/TRF9311CE-AFMS – 10 total
• Features: Customizable, Pressure Sensing, Real Time Clock (RTC), Network, Airflow Measurement Programming

Product Usage Instructions

Introduction

The TrueFit Airflow Measurement System (AFMS) provides accurate outside, return, and supply airflow data for monitoring and control without mechanical limitations or ongoing maintenance issues.

Selecting an AFMS Controller (with inclinometer)

Consider the non-standard features of the unit to select the appropriate controller model based on pressure changes and programming needs.

Selecting Flow Pickup Tubes

Install pickup tubes based on the need for pressure assist measurements. Arrange pickup points in a parallel array covering the area of the supply air duct or fan inlet.

Determining the Number of Pickup Points

Calculate the required number of pickup points based on the airflow measurement requirements.

FAQ

• Q: How far can the controller be mounted from the airflow pickup tubes?
  • A: If the controller will be mounted more than 20 feet away, select a TRF-5901C(E)-AFMS for proper installation.
• Q: Can the controller be programmed for functions other than airflow measurement?
  • A: Yes, select a TRF-5901C(E)-AFMS if customizable programming is needed for additional functions.
• Q: Where should additional flow pickup tubes be installed?
  • A: Additional flow pickup tubes must be installed on either side of the outside air damper for OAD pressure assist or return air damper for RAD pressure assist measurements.

For estimation, try the AFMS Selection Assistant interactive form, a companion to this selection guide

Introduction

The TrueFit Airflow Measurement System (AFMS) reliably provides accurate outside, return, and supply airflow data for monitoring and control. The system delivers accurate, repeatable results on any type of equipment, without the traditionally expected mechanical limitations, performance issues, or ongoing maintenance issues. The system consists of the following components, installed on an AHU, RTU, or unit ventilator:

• One controller with airflow measurement programming
• One inclinometer (included with the controller) mounted on a horizontal outside or return air damper blade
• If only vertical damper blades, one HLO-1050 Linkage Kit
• At least two airflow pickup tubes installed in a pitot array duct on the supply fan inlet, in the supply air duct
• If a TRF-5901C(E)-AFMS is used, one pressure transducer
• If pressure assist measurements are needed (see Considerations on page 4), one additional pressure transducer, is connected to two additional flow pickup tubes that are mounted on both sides of either the outside air damper or return air damper.
• Three temperature sensors for outside, mixed, and return air
• One proportional actuator mounted on the damper shaft

Example Diagrams

Standard Application

OAD (Outside Air Damper) PA (Pressure Assist) Application

RAD (Return Air Damper) PA (Pressure Assist) Application

Selecting an AFMS Controller (with inclinometer)

Considerations

Does the unit have any of these non-standard features?:

• A relief fan that is variable speed, or is operating independent of mixed air damper position
• A return fan that is not controlled by a supply fan/return fan offset
• A bypass damper is utilized to bypass a heat recovery system
• Return VAV boxes
• Supply to return bypass (typically found in zone damper applications, or where a bypass damper is used in place of a VFD)
• Outside and return air dampers that modulate independently
• More than one outside air damper

If yes, the pressure of the unit’s mixed and/or return air sections may change. In that case, select a TRF-5901C(E)-AFMS for (OAD or RAD) pressure assist measurements.

Is customizable programming needed?

If the capability to program the controller for other functions in addition to airflow measurement is needed, select a TRF-5901C(E)-AFMS. The inputs and outputs of a TRF- 9311C(E)-AFMS will be used by the components of the airflow measurement system. Therefore, it must be solely dedicated to airflow measurement.

Where will the controller be mounted?

If the controller will be mounted more than 20 feet from the location of the airflow pickup tubes (see Selecting Flow Pickup Tubes on page 5), select a TRF-5901C(E)-AFMS. A pressure transducer can be mounted closer to the pickup tubes, then wired over a greater distance to the controller.

Selecting Flow Pickup Tubes

Options for Installation Location

The array of supply airflow pickup tubes can be installed in one of two places:

• At the supply air fan inlet
• At least six straight duct widths down the supply air duct

If pressure assist measurements are needed two additional flow pickup tubes must be installed, one on either side of the outside air damper (for OAD pressure assist) or return air damper (for RAD pressure assist).

Arrangement in Parallel Array

The pickup points must be arranged in a parallel array that evenly covers the area of the supply air duct or fan inlet, similar to what is shown below:

Determining the Number of Pickup Points

1. Measure the duct or fan inlet:
   • For a rectangular or square duct, measure the length of the longest side.
   • For a circular duct or the supply fan inlet, measure the diameter.
2. Consult one of the tables below to determine the total minimum number of pickup points needed

FOR A RECTANGULAR OR SQUARE DUCT

If the longest side is less than or equal to:| Total minimum number of pickup points needed is:
4 inches| 2
15 inches| 3
24 inches| 4
35 inches| 5
48 inches| 6
63 inches| 7
80 inches| 8
99 inches| 9
100 inches or greater| 10

FOR A CIRCULAR DUCT OR THE FAN INLET

Duct diameter| Total minimum number of pickup points needed:
<10 inches| 6
≥10 inches| 10

Selecting the Tubes

Select multiple airflow pickup tubes (at least two) from below that are the maximum length that will fit in the space and total to at least the minimum number of pickup points needed:

• SSS-101x models have 3/16” connections for 1/4” OD polyethylene tubing and flat mounting flanges for installation in ducts (or on fan inlets that have struts):
• SSS-1012 One pickup point, 80 mm (about 3”) length tubes
• SSS-1013 Two pickup points, 137 mm (about 5.5”) length tubes
• SSS-1014 Three pickup points, 195 mm (about 8”) length tubes
• SSS-1015 Four pickup points, 252 mm (about 10”)  length tubes

SSS-111x models have 3/16” connections for 1/4” OD polyethylene tubing and right-angled mounting feet for installation on the supply air fan bell.

Single mounting foot:

• SSS-1112 One pickup point, 80 mm (about 3”) length tubes
• SSS-1113 Two pickup points, 137 mm (about 5.5”) length tubes
• SSS-1114 Three pickup points, 195 mm (about 8”) length tubes

Dual mounting feet:

• SSS-1115 Four pickup points, five sections*, 315 mm (about 13”) length tubes
• SSS-1116 Five pickup points, six sections*, 395 mm (about 15.5”) length tubes
• SSS-1117 Six pickup points, seven sections*, 457 mm (about 18”) length tubes

NOTE: The extra section connects the tubes to the second mounting foot, which mounts to the other end of the fan bell (or a midway strut).

Selecting Pressure Transducers

NOTE: Select pressure transducers for a TRF-5901C(E)-AFMS only. TRF- 9311C(E)-AFMS have differential air pressure ports, so a pressure transducer is not necessary to connect the flow pickup tubes.

• For the standard airflow measurement application, select one pressure transducer.
• For airflow measurement applications with pressure assist, select two pressure transducers

TPE-1475-21| –2 to +2” or 0 to 2” wc (–0.5 to +0.5 kPa or 0 to 0.5 kPa)
TPE-1475-22| –10 to +10″ or 0 to 10″ wc (–2.5 to +2.5 kPa or 0 to 2.5 kPa)

Selecting the Mixed Air Temperature Sensor

Averaging sensors are necessary to minimize errors due to stratification or poor airflow mixing in the mixed air chamber. It is recommended to install the largest averaging sensor that the equipment will accommodate. Copper sensors are recommended when the mixed air section is easily accessible. If not easily accessible, a cable sensor can be used

MODEL

| SENSOR TYPE| PROBE TYPE|

PROBE LENGTH

|

ENCLOSURE

|

**CONNECTIONS***

---|---|---|---|---|---
STE-1411|

Duct, Averaging

|

Copper, bend- able

| 6 feet (1.8 m)|

Plastic, UL94-V0, IP65 (NEMA 4X) ABS

|

FT-6 plenum-rated, 22 AWG wire leads

STE-1412| 12 feet (3.6 m)
STE-1414| 20 feet (6.1 m)
STE-1413| 24 feet (7.3 m)
STE-1415|

Flexible, FT-6 plenum-rated cable

| 6 feet (1.8 m)
STE-1416| 12 feet (3.6 m)
STE-1417| 24 feet (7.3 m)

Selecting the Outside Air Temperature Sensor

For units with accessible outside air hoods, select an STE-1412 12-foot bendable copper averaging sensor. For units with inaccessible outside air hoods, or for outside air ducts, select an STE-1404 duct-mounted 12-inch probe with  enclosure. (For sheltered tight fits, an STE-1405 duct-mounted 4-inch probe without enclosure can be used.

MODEL

| SENSOR TYPE| PROBE TYPE|

PROBE LENGTH

|

ENCLOSURE

|

CONNECTIONS

---|---|---|---|---|---
STE-1405|

Duct, Rigid probe

|

1/4-inch OD stainless-steel

| 4 inches (100 mm)| None (mounting bracket only)| 10-ft. FT-6 plenum-rated, 22 AWG cable
STE-1404| 12 inches (300 mm)|

Plastic, UL94-V0, IP65 (NEMA 4X) ABS

| PVC insulated, 22 AWG, wire leads

STE-1412

| OA Hoods, Averaging| Copper, bend- able|

12 feet (3.6 m)

| FT-6 plenum-rated, 22 AWG, wire leads

Selecting the Return Air Temperature Sensor

When possible, select an STE-1404 duct-mounted 12-inch probe with enclosure. For sheltered tight fits, an STE-1405 ductmounted 4-inch probe without enclosure can be used.

MODEL

| SENSOR TYPE| PROBE TYPE|

PROBE LENGTH

|

ENCLOSURE

|

CONNECTIONS

---|---|---|---|---|---
STE-1405|

Duct, Rigid probe

|

1/4-inch OD stainless-steel

| 4 inches (100 mm)| None (mounting bracket only)| 10-ft. FT-6 plenum-rated, 22 AWG cable
STE-1404| 12 inches (300 mm)| Plastic, UL94-V0, IP65 (NEMA 4X) ABS| PVC insulated, 22 AWG, wire leads

Selecting a Proportional Actuator

The unit must have a proportional damper actuator for the AFMS to modulate the damper as needed. If the unit does not have a proportional damper actuator already, select one

Selecting an HLO-1050 Linkage Kit

The AFMS controller’s inclinometer must be mounted on a horizontal-axis damper blade. For units with vertical-axis damper blades, select an HLO-1050 Linkage Kit. The linkages transfer the damper motion to a surface with a horizontal axis (the kit’s inclinometer crankarm), on which the inclinometer can then be mounted. The kit’s damper blade crankarm can be mounted to a damper blade or on a jackshaft using its included jackshaft coupler and V-bolt.If the kit’s axle mount shaft cannot be mounted on a unit’s damper frame (such as when mounting in a duct), select a VTD-0903 right-angle bracket in addition to the kit.

Selecting Tools for Configuration and Operation

The rows in the table below list the processes to set up and operate an AFMS. The columns present the KMC Controls tools that can be used to complete the processes. Consult the table to determine which tools can complete each process and for which AFMS applications. The user interface and setup requirements of each tool varies. For more information, see each tool’s product pages and documents.

Support

Additional resources for product specifications, installation, configuration, application, operation, programming, upgrading and much more are available on the KMC Controls website (www.kmccontrols.com). Log in to see all available files.

References

• KMC Controls | Building Automation and Control Solutions

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