Loren Cook Vari-Flow User manual

VARI-FLOW PRESSURE CONTROLLER IO&M B51004-002
This installation manual provides information for installing
and conguring the Loren Cook Company constant pressure
control system. The system requires a Loren Cook Company
fan with an Electronically Commutated, EC, motor with exter-
nal speed control capability. The manual does not cover any
other installation details or applications.
Carefully read this publication and any sup-
plemental documents prior to any installation
or maintenance procedure.
For additional safety information, refer to AMCA publication
410-96, Safety Practices for Users and Installers of Industrial
and Commercial Fans. This document and all Cook publica-
tions may be obtained from Cook by phoning [phone],
extension 166; by FAX at [phone]; or by e-mail at
[email protected]. All Cook publications are available on
LorenCook.com .
For information and instructions on special equipment, con-
tact Cook at [phone].
Location and Maintenance
Consider the following points while choosing a location for the
Vari-Flow Pressure Controller.
• Install the controller indoors.
• Do not place the controller on the oor.
• Maintain a temperature between 0°C to 40°C (32°F to
104°F). A temperature beyond this range may cause con-
densation and sweating of metal parts.
• Maintain a low humidity, dry, and clean atmosphere. En-
sure that the controller is not in the path of blowing dust,
rain, or snow.
Follow these guidelines prior to installation.
• Clean the components to remove any deposit of dirt,
water, ice, or snow and wipe them dry.
• Dry components using a portable electric heater to
remove any buildup of moisture.
• Allow the cold metal parts to reach room temperature to
avoid sweating.
Installation Warning
Install the Pressure Controller indoors only to avoid additional risks.
Voltage Warning
Low-voltage control wires and line voltage power wires must not be
installed in same conduit. Failure to follow these instructions could
result in malfunction or damage.
Disconnect Warning
ALWAYS disconnect power prior to working on fan. Failure to
comply with these safety precautions could result in property
damage, serious injury, or death.
®
Vari-Flow Pressure Controller
Specication and Installation Instructions
Installation
The following steps and components are important to the
proper operation of the Pressure Controller.
Pressure Tap
Pressure taps are used to connect the controller to the
environment being measured. Use pressure taps by placing
them in the respective duct or room that needs control. Fol-
low these guidelines while mounting the pressure taps.
• Ensure that there are no kinks along the length of the
pressure tube.
• Do not pinch the pressure tube.
• Form a drip loop in the tubing as it enters the pressure
controller. This avoids condensation build up inside the
pressure tube and damages to the controller’s sensor.
• Drip loop should be at least 1” (25 mm) greater than high-
est measured pressure (as measured in inches, w.c.)
factoring in error conditions in the system. (Example: If
static pressure is being measured in 4” w.c., then the
bottom of drip loop should be 5” or more below the high
pressure port.)
Drip Loop
Duct
Low Pressure Port
High Pressure Port

VARI-FLOW PRESSURE CONTROLLER IO&M B51004-002
2
LOW pressure port
HIGH pressure port
Static Pressure Control
• Place the Pressure Controller box as close as possible
to the pressure tap and fan. The location should be easy
to access.
• Keep the length of the wiring between control box and
the fan to 100 feet (30 m) or less.
• Keep the length of the pressure tubing between control
box and pressure taps to 50 feet (15 m) or less.
One Duct Tap
The One Duct Tap maintains a constant pressure in the
duct. The constant pressure is relative to ambient pressure of
space where the Pressure Controller is mounted. To connect
the One Duct Tap:
• Use a 1/8” (3.175 mm) tubing to connect between the
pressure tap and HIGH pressure port on the Pressure
Controller.
• Leave the LOW pressure port open to the atmosphere.
Com
24V~
Prs+
Rev
Dir
Ext
Kcom
Knc
Kno
Open to Atmosphere
Low Pressure Port
High Pressure Port
To Pressure Tap
1/8" (3.175 mm) Tubing
One Room Tap
The One Room Tap maintains a constant pressure in a
room. The constant pressure depends on the value of the
space pressure where the Pressure Controller is mounted.
To connect the One Room Tap:
• Use a 1/8” (3.175 mm) tubing to connect between the
pressure tap and HIGH pressure port on the Pressure
Controller.
• Leave the LOW pressure port open to the atmosphere.
Com
24V~
Prs+
Rev
Dir
Ext
Kcom
Knc
Kno
Open to Atmosphere
Low Pressure Port
High Pressure Port
To Pressure Tap
1/8" (3.175mm) Tubing
Duct Pressure
Location and Positioning
Obtaining optimum results from positioning the duct
pressure tap is dependent on the planning and layout of
the system.
• Install the pressure tap on a duct with a minimum of 1.5
duct diameters of straight duct. Place it away from any
damper, elbow, or other obstructions.
• Ensure that the pressure tap is placed toward the top of
a duct that runs horizontally. This minimizes condensa-
tion entering the tube.
• On a rectangular duct mount, place the pressure tap
away from the corners.
• On a stack system, place the pressure tap at a distance
of one-third from the bottom of the duct.
Installation
• Remove any exterior insulation. If required, insulation
could be replaced after the installation.
• Drill a 3/8” (9.525 mm) hole in the duct where the pres-
sure tap should be installed.
• Place the 6” (152 mm) tube into the hole and move the
mounting base up to the duct in any orientation.
• On a round duct, rotate the tap so that the mounting
holes are aligned with the duct.
• Attach the duct pressure tap to the duct using self-drill-
ing zip screws, tting in the gasket evenly.
• Attach the tubing from the barbed port to the pressure
controller.
Duct Velocity or Air Volume
Location and Positioning
Obtaining optimum results from positioning the pressure
taps is dependent on the planning and layout of the system.
• If you are using total and static probe to measure velocity
pressure, mount the pressure taps in close proximity to
each other but in such a way so as not to interfere with
each other. For this, select a spot in the duct that is at
least 5 duct diameters away from any obstructions such
as elbows, dampers, transitions, or di󰀨users.
Static
Pressure Tap
Low Pressure Port
High Pressure Port
Duct
Total
Pressure Tap
Air Flow
Room Pressure
• Identify the area(s) in which you intend to control the
static pressure.
• Mount the pressure tap near the center of the zone that
you intend to measure.
• Do not mount the pressure tap in an enclosed area such
as a closet and areas that are prone to drafts.

3
VARI-FLOW PRESSURE CONTROLLER IO&M B51004-002
Two Room Taps
The Two Room Taps maintain a constant di󰀨erential pres-
sure between two rooms. This constant di󰀨erential pressure
enables the controller to monitor and regulate the pressure
through the Pressure Controller when placed at a remote lo-
cation. To connect the Two Room Taps:
• Use a 1/8” (3.175 mm) tubing to connect between the
pressure tap in the high pressure room and the HIGH
pressure port on the Pressure Controller.
• Use a 1/8” (3.175 mm) tubing to connect between the
pressure tap in the low pressure room and the LOW
pressure port on the Pressure Controller.
Com
24V~
Prs +
Rev
Dir
Ext
Kcom
Knc
Kno
Static Pressure Tap
Low Pressure Port
High Pressure Port
Total Pressure Tap
1/8" (3.175mm) Tubing
Velocity Pressure Control
One Duct Static Tap and One Duct Total Tap
The One Duct Static Tap and One Duct Total Tap maintain
a constant velocity pressure in a duct. This constant velocity
pressure enables the controller to modulate the airow auto-
matically to compensate for lter or coil loading. To connect
the Duct Static and Total Tap:
• Use a 1/8” (3.175 mm) tubing to connect between the
total pressure tap and HIGH pressure port on the Pres-
sure Controller.
• Use a 1/8” (3.175 mm) tubing to connect between the
static pressure tap and LOW pressure port.
Static
Pressure Tap
Low Pressure Port
High Pressure Port
Duct
Total
Pressure Tap
Air Flow
In this conguration, the Pressure Controller maintains a
velocity pressure by measuring and maintaining the di󰀨er-
ence between total and static pressure read at the HIGH and
LOW pressure ports. To set up the controller, calculate the
required velocity pressure based on the intended CFM and
duct area using the following formula:
where A is the duct area in ft2
Set the desired pressure setpoint parameters from the Pro-
gramming menu (see Programming). To verify the airow
calculation, take external CFM measurements and calculate
the velocity pressure until the desired airow is achieved.
Step Display Description Values
1Pr:X.XXX
Sp:X.XX
Operation Mode & Setpoint Adjustment
When 24 Vac is supplied to the unit, the SPC displays the actual
pressure (Pr) and the setpoint of the static pressure (Sp). Use the arrow
keys to change the setpoint.
Increments of 0.01
Units - in w.c. (inches of water column)
Range - 0.00 to 1.99
2Deadband
(range: 0.000-0.243)
Deadband Adjustment
Not generally important for EC motor control
Default: 0.014 (SPC 1.0), 0.0014 (SPC 0.1)
Increment: 0.005 (SPC 1.0), 0.0005 (SPC 0.1)
3Response Speed:
(range: 1-25)
Response Speed Adjustment
Prevents unjustied changes due to a temporary surge of static
pressure, which could a󰀨ect the system. To increase system stability,
we recommended setting the Response Speed to lower end of range
(setting 1 or 2).
1 to 25 (factory setting: #2)
1 lowest: (100 mV/sec, 100 seconds for a 0-10 Vdc output).
25 fastest: (1.78 V/sec, 5.6 seconds for 0-10 Vdc output).
4Cntl Out
Output Signal Adjustment
The conguration of the output signal applies to both direct acting and
reverse acting.
▲ or ▼ = 0-10 Vdc / 2-10 Vdc
5Direct Act: Direct acting output conguration ▲ or ▼ = Vdc or mA (Set to Vdc for EC motor control)
6Reverse Act: Reverse acting output conguration ▲ or ▼ = Vdc or mA (Set to Vdc for EC motor control)
7Contact: Relay conguration Direct or Reverse
8Contact On: Relay SETPOINT (Sp) to come ON Contact Direct: 0.31-2.00 ”wc Contact Reverse: 0.00-0.31 ”wc
9Contact O󰀨: Relay SETPOINT (Sp) to turn OFF Contact Direct: 0.00-0.31 ”wc Contact Reverse: 0.31-2.00 ”wc
Programming
Press the menu button to enter programming mode. Once in programming mode, the menu button always advances to
the next step. Use the arrow keys to change the value of the current menu item. Press and hold an arrow key to scroll rapidly
through the values. Changes are automatically saved. The Vari-Flow Pressure Controller automatically exits the menu after 20
seconds of inactivity.

VARI-FLOW PRESSURE CONTROLLER IO&M B51004-002
4
Corporate O󰀩ces 2015 E. Dale Street Springeld, MO 65803
Phone [phone] Fax [phone] LorenCook.com
Limited Warranty
Loren Cook Company warrants that your Loren Cook fan was manufactured free of defects in materials and workmanship, to the extent stated herein. For a period of one (1)
year after date of shipment, we will replace any parts found to be defective without charge, except for shipping costs which will be paid by you.
This warranty is granted only to the original purchaser placing the fan in service.
This warranty is void if the fan or any part thereof has been altered or modied from its original design or has been abused, misused, damaged or is in worn condition or if the fan
has been used other than for the uses described in the company manual. This warranty does not cover defects resulting from normal wear and tear.
To make a warranty claim, notify Loren Cook Company, General O󰀩ces, 2015 East Dale Street, Springeld, Missouri 65803-4637, explaining in writing, in detail, your complaint
and referring to the specic model and serial numbers of your fan. Upon receipt by Loren Cook Company of your written complaint, you will be notied, within thirty (30) days of our
receipt of your complaint, in writing, as to the manner in which your claim will be handled. If you are entitled to warranty relief, a warranty adjustment will be completed within sixty
(60) business days of the receipt of your written complaint by Loren Cook Company.
This warranty gives only the original purchaser placing the fan in service specically the right. You may have other legal rights which vary from state to state.
For fans provided with motors, the motor manufacturer warrants motors for a designated period stated in the manufacturer’s warranty. Warranty periods vary from manufacturer
to manufacturer. Should motors furnished by Loren Cook Company prove defective during the designated period, they should be returned to the nearest authorized motor service
station. Loren Cook Company will not be responsible for any removal or installation costs.
DECEMBER 2018
Controller does not hold setpoint pressure
Cause:
∙Incorrect minimum distance
∙Kinks or punctures in the tubing.
Corrective Action:
∙Ensure that the pressure taps are located at a minimum distance
of 1.5 duct diameters upstream or downstream from any dimensional
change, elbow, damper, or other obstruction.
∙ Verify and ensure that there are no kinks or punctures in the tubing
between the Pressure Controller and the pressure taps.
Unstable Fan Speed
Cause:
∙ Kinks or punctures in the tubing.
∙ Response Speed set too high.
Corrective Action:
∙ Verify and ensure that there are no kinks or punctures in the tubing
between the Pressure Controller and the pressure taps.
∙ Adjust the response speed from the Programming Menu (see Step
3 - Programming).
PROBLEM AND POTENTIAL CAUSE
TroubleshootingContact Modes/Actions
Wiring
We strongly recommend that each product be wired to a separate grounded transformer and that the transformer shall service
only these products. This precaution will prevent interference with and/or possible damage to incompatible equipment.
OFF ON
- +
OFF
Legend
Dashed = Open
Solid = Closed
ON
- +
Knc = Closed
Kno = Open
Knc = Open
Kno = Closed
Knc = Open
Kno = Closed
Knc = Closed
Kno = Open
Pressure
Differential
Pressure
Differential
Direct Acting
Reverse Acting