Price MFD Series User manual

MANUAL – INSTALLATION
Modular Floor Diffusers
MFD Series
v103 –Issue Date: 03/31/21
© 2021 Price Industries Limited. All rights reserved.

MODULAR FLOOR DIFFUSERS
TABLE OF CONTENTS
General Overview
Introduction................................................................... 1
General Safety Guidelines..............................................1
Safety Symbols ............................................................. 1
System Overview
Interior Zones ................................................................ 2
Product Overview
Modular Floor Diffusers..................................................3
Diffuser Face Options.................................................... 4
Mounting Ring Options.................................................. 4
Basket/Damper Options................................................ 5
Installation & Mounting Instructions
Installation Instructions .................................................. 6
Modular Floor Boot Installation .................................... 12
Cleaning Instructions................................................... 13

1
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
GENERAL OVERVIEW
Introduction
In this manual, you will find technical descriptions and diagrams of underfloor system components along with their installation
instructions. Practical guidelines and recommendations are also provided. If more information is required about this equipment,
please contact an Price sales representative.
General Safety Guidelines
This document is intended for use by owner-authorized operating/service personnel who are expected to possess the required
training to enable them to perform their tasks properly and safely. This individual must have read and understood this document
and any referenced materials prior to performing any task on this equipment. Also, it is essential that this individual be familiar with
and comply with all applicable governmental standards and regulations pertaining to the task in question. This individual must also
verify that installation and connections comply with local building codes. It is the obligation and responsibility of the operating/
service personnel to identify and recognize these inherent hazards, protect themselves, and proceed safely in completing their
tasks. Failure to comply with any of these requirements could result in severe personal injury or death to themselves and people at
the site, as well as serious damage to the equipment and the property in which it is situated.
The equipment discussed in this manual is relatively complicated apparatus and must be handled with the necessary precautions.
Individuals may be exposed to certain components or conditions such as refrigerants, oils, materials under pressure, rotating
components, and both high and low voltage during installation, operation, maintenance or service of this equipment. If misued or
mishandled, each item has the potential to cause bodily injury or death.
Safety Symbols
The following symbols are used in this document to alert the reader to areas of potential hazard:
NOTE: Used to highlight additional information helpful to the reader.
CAUTION
Failure to observe may result in equipment damage.
WARNING
Failure to observe may result in personal injury, death or
equipment damage.

2MODULAR FLOOR DIFFUSERS - Manual |priceindustries.com
MODULAR FLOOR DIFFUSERS
SYSTEM OVERVIEW
CONSTANT AIR VOLUME - COOLING ONLY
VARIABLE AIR VOLUME - COOLING ONLY
Interior Zones
CONSTANT AIR VOLUME - COOLING ONLY
Typically, interior zones have relatively stable loads hence
constant volume supply is often employed. A typical interior
zone consists of contant volume or constant pressure turbulent
floor twist outlets installed in a large, common plenum space.
In this method the entire plenum space is treated as one zone
and, under fluctuating loads, the amount of air delivered to
the space is regulated by the relative pressure in this plenum,
modulated by a single point of control. Manual face-adjustable
diffusers provide occupant control of airflow volume.
VARIABLE AIR VOLUME - COOLING ONLY
In the case an open plenum is desired to be divided into
several zones, variable air volume control is possible with the
use of devices installed under the diffuser or with the use of
a variable volume basket. The variable volume baskets are
controlled by the UMC3. The UMC3 would open and close
the diffusers releasing air from the pressurized plenum. The
variable volume (VAV) diffusers require a 24 VAC signal which is
provided by the UMC3 to modulate the actuators. Meanwhile,
the UMC3 accepts a 0 to 10 VDC cooling signal either from
a manual control signal or from a thermostat. The UMC3
modulates the airflow from 0% to 100%.

3
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
PRODUCT OVERVIEW
Modular Floor Diffusers
The Modular Floor Diffuser Twist
Pattern (MFD-TP) is designed with
a twist effect using radial slots in
combination with an inclined discharge.
This generates a vertical supply with
very high induction due to the turbulent
flow. This symmetrical discharge is ideal
for mixing within the occupied zone.
The Modular Floor Diffuser
Displacement Pattern (MFD-DP)
is used where low, floor level flow is
required. The diffuser slots discharge
the air horizontally across the floor
where it can absorb the heat load and
rise to the return grilles in the ceiling.
Polymer 8 in. diffusers are available in
black and dusty grey finishes.
Aluminum diffusers are available in 8
and 10 in.
MFD-TP
MFD-DP
Initials
Completion dateFactory order no OperatorSch datePart qty Comment/TagIssued date Blank qty
of
11
Solid Edge
Print Date: 10/28/2016 - Page 5 of 16 Replacement drawings.dftPrint Date: 10/28/2016 - Page 5 of 16 Replacement drawings.dft
Network File Location: T:\Underfloor\ROUNDFLOOR\ER160283 - ROUNDFLOOR PRODUCT LINE CHANGES\OPERATION AND MAINTENANCE MANUAL\MODELS TO RENDER\Update for Manual\Page 5 of 16 Replacement drawings.dft
ALUMINUM DESIGN POLYMER DESIGN
ALUMINUM DESIGN
POLYMER DESIGN
MOUNTING RING DIFFUSER
AIRFLOW POSITION
INDICATOR
ON FACE
AIRFLOW POSITION
INDICATOR
ON FACE
DIFFUSER
MOUNTING RING
Initials
Completion dateFactory order no OperatorSch datePart qty Comment/TagIssued date Blank qty
of
11
Solid Edge
Print Date: 10/28/2016 - Page 5 of 16 Replacement drawings.dftPrint Date: 10/28/2016 - Page 5 of 16 Replacement drawings.dft
Network File Location: T:\Underfloor\ROUNDFLOOR\ER160283 - ROUNDFLOOR PRODUCT LINE CHANGES\OPERATION AND MAINTENANCE MANUAL\MODELS TO RENDER\Update for Manual\Page 5 of 16 Replacement drawings.dft
ALUMINUM DESIGN POLYMER DESIGN
ALUMINUM DESIGN
POLYMER DESIGN
MOUNTING RING DIFFUSER
AIRFLOW POSITION
INDICATOR
ON FACE
AIRFLOW POSITION
INDICATOR
ON FACE
DIFFUSER
MOUNTING RING

4MODULAR FLOOR DIFFUSERS - Manual |priceindustries.com
MODULAR FLOOR DIFFUSERS
PRODUCT OVERVIEW
Diffuser Face Options
A. Plastic diffusers and can be
mounted in either RPF or ZC
configurations.
B. Aluminum diffusers and can be
mounted in either RPF or ZC
configurations. ZC available
with ZC adapter.
Mounting Ring Options
A. Ring Press Fit (RPF) mounting
ring uses a soft rubberized seal
to hold the mounting ring in the
bore. RPF comes standard with
all modular floor mounting rings.
NOTE: The maximum suggested
carpet thickness used for Ring
Press Fit is 5/16 in., carpets
beyond that thickness should
use Zip-Clip mounting.
B. Zip Clip (ZC) mounting ring uses
the RPF seal to center the ring in
the bore and three (3) clips which
ratchet in place to secure the
mounting ring to the floor. If the
floor tile has a contoured bottom,
care must be taken to ensure all
three zip clips can tighten against
the tile.
C. Stepped Bore does not
require a mounting ring; the
floor is cut to size to fit only the
diffuser face.
MODULAR FLOOR DIFFUSERS
DISPLACEMENT PATTERN
ALUMINUM
TWIST PATTERN
POLYMER
MOUNTING RING
ALUMINUM ADAPTERS
ZIP CLIP
STEPPED BORE

5
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
PRODUCT OVERVIEW
Basket/Damper Options
The seven standard 8 in. distributor baskets (B, BS, DBV, DB, DBS, DBA, DBAS) and four standard 10 in. distributor baskets (B,
DB, DBA, DBV) allow for even distribution of supply air through the round floor diffuser. The basket is also used to catch debris that
may fall through the diffuser face.
B – BASIC BASKET DB – BASKET WITH DAMPER
DBAS – SHORT 2 IN. BASKET WITH FACE
ADJUSTABLE DAMPER
RBC – BASKET WITH COLLAR FOR DUCT CONNECTION
DBV – ELECTRONICALLY CONTROLLED VAV BASKET
RPN – RELATIVE PRESSURE NODE (AVAILABLE WITH PCU)
BOP – BLANK OFF PLATE
BS – SHORT 2 IN. BASIC BASKET DBS – SHORT 2 IN. BASKET WITH DAMPER
DBA – BASKET WITH FACE ADJUSTABLE DAMPER

6MODULAR FLOOR DIFFUSERS - Manual |priceindustries.com
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
Installation Instructions
The components for the modular floor diffuser assembly
are shipped assembled. The following is a recommended
installation guide.
STEP 1: Cut the hole in the floor/tile according to the following
table:
Hole Sizes
MFD
Size Ring Press Fit / Zip Clip
8 in. Ø8.50
+.125
+0.00 (216 ± 3/-0)
10 in.* Ø10.50
+.125
+0.00 (267 ± 3/-0)
*10 in. available in aluminum only
STEP 2: Secure the mounting ring into the floor cutout:
A. RPF rings do not require additional hardware; the
rubberized seal prevents the unit from accidentally
being dislodged during normal foot traffic as shown in
Figure 1. Do not use glue!
B. Zip Clip mounting uses three (3) clips that lock the
ring in place. The clips can be inserted onto the legs
of the mounting ring from the roomside opening and
locked into place, as shown in Figure 2.
NOTE: For aluminum mounting rings the zip clip adapter must
first be snapped into place before placing the zip clips, as
shown in Figure 3.
BASKET
EF
Floor Tile
Zip
Clip
PHILLIPS HEAD
FIGURE 1: RPF RINGS
FIGURE 2: ZIP CLIP MOUNTING
FIGURE 3: ZIP CLIP ADAPTER FOR
ALUMINUM MOUNTING RINGS

7
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
FIGURE 4: BASKET TAB ALIGNMENT
FIGURE 5: DAMPER LEG ALIGNMENT
FIGURE 6: MINIMUM AIRFLOW KNOB
FIGURE 7: DBA BASKET
If using a DBV basket skip step 3 and go straight to step 4,
otherwise proceed to step 3 below.
STEP 3: The basket and damper assembly can now be placed
into the mounting ring:
A. The basket should be aligned such that the tabs
on the basket flange aligns with the notch in the
mounting ring. The tabs are 171° and should only be
installed in one orientation, refer to Figure 4.
B. The damper must be installed such that the thinner
web portion on the damper legs aligns with the raised
tab on the basket, refer to
Figure 5.
C. Using the minimum airflow knob, rotate until the
indicator points to the desired min airflow as shown
in Figure 6. Press down on the damper to ensure it
does not slip above the min airflow knobs.
D. For DBA installation, the damper can be placed into
basket and rotated until it drops into place, in the
correct orientation, refer to Figure 6 and Figure 7.
NOTE: The airflow arrow will point to the “open - closed” text or
the curved triangular air flow bar on the mounting rings.

8MODULAR FLOOR DIFFUSERS - Manual |priceindustries.com
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
STEP 3 CONTINUED:
E. RPN and RBC are installed into the mounting ring,
following the same procedure as other baskets. Two
protrusions prevent the diffuser from rotating. Figure
8shows the RBC.
F. 1/4 in. pressure hose is connected to the top or
bottom fitting on RPN to measure the pressurized
underfloor plenum or occupied zone, respectively.
Figure 9 shows the the Blank Off Plate and Figure 10
shows the installed RPN.
FIGURE 8: RBC
FIGURE 9: BLANK OFF PLATE
FIGURE 10: RPN

9
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
STEP 4: Variable Volume Diffuser Basket (DBV) Installation
The Variable Volume Diffuser Basket (DBV) is designed to allow
even distribution of supply air through the modular floor diffuser
core while integrating into a VAV cooling system. It utilizes
a 24 VAC floating point actuator to modulate a gasketed
control damper based on a signal from the building control
system or from the Price PCM - Power and Control Module.
The actuator modulates the damper to throttle the supply air
from the pressurized underfloor plenum to the occupied zone.
The motorized damper provides control of cooling flows from
maximum to near shut-off. The DBVs can be daisy chained
from one unit to another using the provided plenum rated
cable with plug-in modular connectors.
INSTALLATION INSTRUCTIONS
1. Locate the mounting ring in the hole in the floor tile.
2. Connect the control wire to the DBV through the floor,
Figure 11.
3. Insert the DBV, ensuring that the tabs on the DBV align
with the holes in the mounting ring, Figure 12.
BASKET SIZE OPTIONS:
Diffuser Basket Diameter “A”
8” 7.400” (188)
10” 9.400” (239)
DBV
FIGURE 11: CONNECT CONTROL WIRE TO DBV
FIGURE 12: INSERT DBV
Underfloor Products
SERVICE & INSTALLATION MANUAL
www.price-hvac.com 27
Variable Volume Diffuser Basket (DBV) – Product Overview
Variable Volume Diffuser Basket (DBV) - Installation Instructions
1. Locate the mounting ring in the hole in the floor tile.
2. Connect the control wire to the DBV through the floor.
3. Insert the DBV, ensuring that the tabs on the DBV align
with the holes in the mounting ring.
4. Place diffuser face on mounting ring.
The Variable Volume Diffuser Basket (DBV) is designed to allow
even distribution of supply air through the round floor diffuser
core while integrating into a VAV cooling system. It utilizes a
24 VAC floating point actuator to modulate a gasketed control
damper based on a signal from the building control system
or from the Price UMC – Underfloor Modulating Controller.
The actuator modulates the damper to throttle the supply air
from the pressurized underfloor plenum to the occupied zone.
The motorized damper provides control of cooling flows from
maximum to near shut-off. The DBVs can be daisy chained
from one unit to another using the provided plenum rated cable
with plug-in modular connectors.
Supply and install Price DBV, black Distributor Basket with
integral VAV Damper. The DBV shall be supplied with a floating
point actuator furnished with two modular jacks (RJ12) for
system connections and one 25 foot plenum rated modular
plug-in control cable. The electric actuator shall be 24 VAC bi-
directional, directly coupled to the damper screw. The damper
shall move from a full open position to a fully closed position
in 90 seconds. The actuator must be capable of operating in
the stalled position without overheating or mechanical damage.
Peripheral gasket shall be provided on the control damper and
shall allow zero leakage at 0.05 “wc when fully closed.
DBV
Steps 1 and 2
Steps 1 and 2
Underfloor Products
SERVICE & INSTALLATION MANUAL
www.price-hvac.com 27
Variable Volume Diffuser Basket (DBV) – Product Overview
Variable Volume Diffuser Basket (DBV) - Installation Instructions
1. Locate the mounting ring in the hole in the floor tile.
2. Connect the control wire to the DBV through the floor.
3. Insert the DBV, ensuring that the tabs on the DBV align
with the holes in the mounting ring.
4. Place diffuser face on mounting ring.
The Variable Volume Diffuser Basket (DBV) is designed to allow
even distribution of supply air through the round floor diffuser
core while integrating into a VAV cooling system. It utilizes a
24 VAC floating point actuator to modulate a gasketed control
damper based on a signal from the building control system
or from the Price UMC – Underfloor Modulating Controller.
The actuator modulates the damper to throttle the supply air
from the pressurized underfloor plenum to the occupied zone.
The motorized damper provides control of cooling flows from
maximum to near shut-off. The DBVs can be daisy chained
from one unit to another using the provided plenum rated cable
with plug-in modular connectors.
Supply and install Price DBV, black Distributor Basket with
integral VAV Damper. The DBV shall be supplied with a floating
point actuator furnished with two modular jacks (RJ12) for
system connections and one 25 foot plenum rated modular
plug-in control cable. The electric actuator shall be 24 VAC bi-
directional, directly coupled to the damper screw. The damper
shall move from a full open position to a fully closed position
in 90 seconds. The actuator must be capable of operating in
the stalled position without overheating or mechanical damage.
Peripheral gasket shall be provided on the control damper and
shall allow zero leakage at 0.05 “wc when fully closed.
DBV
Steps 1 and 2
Steps 1 and 2
7.313 [186]
6.563 [167]
TYP MOUNTING FLANGE
FOR ROUND FLOOR
DIFFUSERS
BI-DIRECTIONAL
ACTUATOR
RJ12 INTERFACE FOR
CONNECTION TO
PRICE UNDERFLOOR
SYSTEMS
BASKET VANES
VAV DAMPER
A
AIR SEAL GASKET
PRESS FIT GASKET
DIFFUSER SIZE BASKET DIAMETER "A"
8" 7.400" (188)
10" 9.400" (239)
BASKET SIZE OPTIONS:

10 MODULAR FLOOR DIFFUSERS - Manual |priceindustries.com
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
FIGURE 13A: ALUMINUM DIFFUSER FACE
INSTALLATION TOP VIEW
FIGURE 14A: ALUMINUM DIFFUSER FACE
INSTALLATION BOTTOM VIEW
FIGURE 14B: POLYMER DIFFUSER FACE
INSTALLATION BOTTOM VIEW
STEP 5: The diffuser face can now be installed into the
mounting ring:
A. If the assembly is not face adjustable (DB, DBS,
MDB), then the face can be dropped in place and the
unit is complete, refer to Figures 13A and 13B.
B. If the assembly is face adjustable, the tabs on the
damper must align and lock into the bottom of the
diffuser face, Figure 14A and Figure 14B. The arrow
on the diffuser face should also point in-between the
open and close labels on the mounting ring as shown
in Figures 13A and 13B.
FIGURE 13B: POLYMER DIFFUSER FACE
INSTALLATION TOP VIEW

11
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
STEP 6: Final Inspection:
The diffuser should sit flush in the mounting ring and if face
adjustable, should allow rotation of the damper quite easily
between open and close positions. When a downward force is
applied to the face, the diffuser locks in place. This is to reduce
the chance of inadvertent rotation when walking across the
diffuser. Therefore, excessive downward force on the face will
prevent rotation of the diffuser.
DIFFUSER FLUSH WITH MOUNTING RING

12 MODULAR FLOOR DIFFUSERS - Manual |priceindustries.com
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
Modular Floor Boot Installation
The Price modular floor boots are specially designed for
mounting on the bottom of a floor tile under a modular floor
diffuser. A top plate with a discharge hole outlet ensures proper
sealing to the diffuser even when structural depressions exist
on the bottom surface of the floor tiles.
The MFB-F enables a ducted connection to a fan powered
terminal unit. It is designed to control the supply of conditioned
air to a space which has a variable occupancy schedule.
The MFB-HC is used in conjunction with heat/cool
applications. The MFB-HC comes with two (2) inlets, one (1)
for connecting to a fan powered terminal unit and the second
to admit supply air from the pressurized plenum. The MFB-HC
comes complete with a 24 VAC floating point actuator on the
inlet open to the plenum to cycle a gasketed control damper
through a 90° range of movement. The controller modulates
based on a call for cooling either directly from the building
control system, from the Price PCM (UMC3 or UMCB). A 25
foot plenum rated control cable is provided with each unit for
connecting to a controller or daisy chaining to multiple boots.
Supply air is either provided through an open connection to the
pressurized plenum or via a ducted fan powered terminal unit.
PLENUM BOOT SIZE
BOOT
SIZE
SIDE
LENGTH (A)
TILE
CENTER (D)
SIDE
LENGTH (E)
SIDE
LENGTH (F)
8B 10.000 (254) 6.750 (171) 8.960 (228) 8.960 (228)
10B 12.000 (305) 8.000 (203) 4.710 (120) 4.710 (120)
PLENUM INLET (VC, HC) & FAN INLET (F, FC)
NOM. DUCT SIZE FAN INLET (B) PLENUM INLET ('C)
6 (152) 5.88 (149)
8 (203) 7.88 (200)
2
2
4
D
D
Floor Panel
Gasket
Strip
Mounting
Flange
MFB
Type
4
4
F
E
MFB INSTALLATION
MFB-F
MFB-HC
INSTALLATION INSTRUCTIONS
1. Cut hole in tile (hole must be located as marked on submittal
and installation page).
2. Fasten the flange on the floor tile by screwing through the
outer hole labeled 2. The gasket will cover the holes. Ensure
that self-drilling screws are used.
3. Place MFB over flange in with small holes aligned, the large
holes provide clearance for the fastener used in Step 2.
4. Fasten MFB to mounting flange and floor tile by screwing
through holes labeled 4.
NOTE: Adjust set screw and damper to minimum airflow for balancing.
9.50 (241)
A A A
B
9.50 (241)
1.00 (25)
1.00 (25)
FAN AIRFLOW
A
A
A
9.50 (241)
9.50 (241) B
7.00 (178)
1.00 (25)
C
PLENUM AIRFLOW
FAN AIRFLOW
HEAT COOL
FOR MFB-F:
FOR MFB-HC:
9.50 (241)
A A A
B
9.50 (241)
1.00 (25)
1.00 (25)
FAN AIRFLOW
A
A
A
9.50 (241)
9.50 (241) B
7.00 (178)
1.00 (25)
C
PLENUM AIRFLOW
FAN AIRFLOW
HEAT COOL
FOR MFB-F:
FOR MFB-HC:

13
priceindustries.com |MODULAR FLOOR DIFFUSERS - Manual
MODULAR FLOOR DIFFUSERS
INSTALLATION & MOUNTING INSTRUCTIONS
DIFFUSER FACE CLEANING
Cleaning Instructions
The face can be cleaned from liquids or
food by wiping the face with a moist rag.
For more stubborn stains use
disinfectant wipes.
The diffuser basket should be
periodically cleaned by removing
the diffuser face from the ring and
vacuuming any particles that have
accumulated in the catch basket.
The diffuser face can be removed by
inserting the diffuser face removal tool,
into the notches carved out along the
diffuser face. Once the tool is inserted
simply bend back the clip holding the
diffuser face in place and pull out the
diffuser.
DIFFUSER FACE REMOVER TOOL
INSERT DIFFUSER
FACE REMOVER TOOL
Name Description Mounting Options Basket Options Standard Finish
MFD-TP - Polymer Twist diffuser
High induction mixing
Polymer construction
8 in. only
Standard with Ring
Press Fit (RPF)
Zip-Clip
No Fastening
8 in. or 10 in.: B,
DB, DBA, DBV,
8 in. only: BS,
DBS, DBAS,
MB, MDB,
MDBA
Black
Dusty Grey (DG)
MFD-DP - Polymer Displacment diffuser
Non-mixing low throw
Polymer construction
8 in. only
Black
Dusty Grey (DG)
MFD-TP - Aluminum Twist diffuser
High induction mixing
Aluminum construction
8 in. or 10 in.
Fine Aluminum Finish
MFD-DP - Aluminum Displacement diffuser
Non-mixing low throw
Aluminum construction
8 in. or 10 in.
Fine Aluminum Finish

This document contains the most current product information as of this printing.
For the most up-to-date product information, please go to priceindustries.com
© 2021 Price Industries Limited. All rights reserved.