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VARITHERM SMALL SQUARE VAV DIFFUSER
SYSTEM BALANCING (VKD-HC, VKD-C)
VAV systems are balanced for design air volume at maximum air flow and systems using Varitherm Small Square VAV VAV diffusers
are no exception. When all the Varitherm Small Square VAV diffusers are set for maximum air flow by fully opening them, the
system is really a constant air volume system and is balanced as a constant volume system. Balancing dampers are best located
at the takeoff before the runout to the Varitherm Small Square VAV diffuser.
1.
Prepare the system for balancing. (Make necessarychecks
for diversity, fan capacities, fan rotation,miminum outside
air requirements, duct leaks andstatic pressure controller
design settings. Set outsideair control damper for mini-
mum air and return aircontrol damper for maximum air.)
2.
Open Varitherm Small Square VAV diffusers.
a.
Open appearance panel.
To remove the appearance panel:
1.
Open appearance panel as described above.
b. Using a flat blade screwdriver or coin, turn thedamper
2. Rotate the appearance panel away from the latch clip
opening cam clockwise until the damperblades are
bracket to force the hinge hooks open on the panel.
fully open and the blade tips toucheach other.
3. Slightly lift the panel to remove from the hinges.
See Fig. 3.
To reattach the appearance panel:
To remove the appearance panel:
c.
Close appearance panel.
1.
Hang the appearance panel on the hinges.
1.
Open appearance panel as described above.
2. Press the hinge hooks against the panel to close
3.
Start fans, adjust system for 100% air flow and
2. Rotate the appearance panel away from the latch clip
around the hinge brackets.
bracket to force the hinge hooks open on the panel.
makesystem checks. (Measure static pressure across
3. Close panel as described above.
3. Slightly lift the panel to remove from the hinges.
filtersand coils and at sensor for static pressure controller.
SYSTEM BALANCING (TK-HC, TK-C)
To reattach the appearance panel:
Measure supply, return and branch duct air flow.)
VAV systems are balanced for design air volume at
1.
Hang the appearance panel on the hinges.
maximum air flow and systems using Therma-Fuser VAV
4.
Place a direct reading diffuser balancing hood over theface
2. Press the hinge hooks against the panel to close
diffusers are no exception. When all the Therma-Fuser
around the hinge brackets.
of each Varitherm Small Square VAV diffuser and adjust
diffusers are set for maximum air flow by fully opening
3. Close panel as described above.
them, the system is really a constant air volume system
damperat duct takeoff to obtain maximum design air
and is balanced as a constant volume system. Balancing
volume.If a velocity meter is used, measure discharge
dampers are best located at the takeoff before the
SYSTEM BALANCING (TK-HC, TK-C)
runout to the Therma-Fuser diffuser.
velocityat the housing (See Fig. 3). Multiply the velocity in
VAV systems are balanced for design air volume at
1.
Prepare the system for balancing. (Make necessary
fpmtimes A k of .12 ft
maximum air flow and systems using Therma-Fuser VAV
2
checks for diversity, fan capacities, fan rotation,
diffusers are no exception. When all the Therma-Fuser
miminum outside air requirements, duct leaks and
5.
Return Varitherm Small Square VAV diffusers to operating
diffusers are set for maximum air flow by fully opening
static pressure controller design settings. Set outside
them, the system is really a constant air volume system
condition.
air control damper for minimum air and return air
and is balanced as a constant volume system. Balancing
control damper for maximum air.)
dampers are best located at the takeoff before the
a.
Open appearance panel.
runout to the Therma-Fuser diffuser.
2. Open Therma-Fuser diffusers.
a.
Open appearance panel.
b. Turn damper opening cam to allow damper blades
1.
Prepare the system for balancing. (Make necessary
b.
Using a flat blade screwdriver or coin, turn the
checks for diversity, fan capacities, fan rotation,
to close.
damper opening cam clockwise until the damper
miminum outside air requirements, duct leaks and
blades are fully open and the blade tips touch
static pressure controller design settings. Set outside
c.
Close appearance panel.
each other. See
air control damper for minimum air and return air
control damper for maximum air.)
c.
Close appearance panel.
Balancing (VKD-D)
2. Open Therma-Fuser diffusers.
1.
The damper blade opening is factory set at 3/4inch/19mm
a.
Open appearance panel.
Fig 2. Turn damper opening cam to open for balancing
(See Fig. 4). Readjust where necessary byturning the
b.
Using a flat blade screwdriver or coin, turn the
Damper Opening Cam
damper opening cam clockwise until the damper
damper opening cam (See Fig. 2).
blades are fully open and the blade tips touch
each other. See
2.
Place a direct reading diffuser balancing hood over theface
c.
Close appearance panel.
of each VKD-D diffuser and adjust damper at ducttakeoff
to obtain design air volume. If a velocity meteris used,
Fig 2. Turn damper opening cam to open for balancing
measure discharge velocity at the housing (See Fig. 3).
Damper Opening Cam
Multiply the velocity in fpm times A k of .12 ft
in cfm.
3. Start fans, adjust system for 100% air flow and make
to get air flow in cfm.
Fig. 2.
Fig. 2.
toget air flow
2
priceindustries.com/vavdiffusers | VARITHERM SMALL SQUARE VAV DIFFUSER - Manual
maximum air flow and systems using Therma-Fuser VAV
diffusers are no exception. When all the Therma-Fuser
diffusers are set for maximum air flow by fully opening
them, the system is really a constant air volume system
and is balanced as a constant volume system. Balancing
dampers are best located at the takeoff before the
runout to the Therma-Fuser diffuser.
1.
Prepare the system for balancing. (Make necessary
checks for diversity, fan capacities, fan rotation,
miminum outside air requirements, duct leaks and
static pressure controller design settings. Set outside
air control damper for minimum air and return air
control damper for maximum air.)
2. Open Therma-Fuser diffusers.
a.
Open appearance panel.
b.
Using a flat blade screwdriver or coin, turn the
damper opening cam clockwise until the damper
blades are fully open and the blade tips touch
each other. See
Fig. 2.
c.
Close appearance panel.
FIG. 2 TURN DAMPER OPENING CAM TO OPEN FOR BALANCING
Fig 2. Turn damper opening cam to open for balancing
Damper Opening Cam
5. Return Therma-Fuser diffusers to operating condition.
a.
Open appearance panel.
b.
Turn damper opening cam to allow damper blades to close.
c.
Close appearance panel.
Fig 3. Measuring Discharge Velocity
Figure 3 @200%
5. Return Therma-Fuser diffusers to operating condition.
a.
Open appearance panel.
b.
3. Start fans, adjust system for 100% air flow and make
Turn damper opening cam to allow damper blades to close.
system checks. (Measure static pressure across filters
c.
Close appearance panel.
and coils and at sensor for static pressure controller.
FIG. 3 MEASURING DISCHARGE VELOCITY
Measure supply, return and branch duct air flow.)
Fig 3. Measuring Discharge Velocity
Figure 3 @200%
4. Place a direct reading diffuser balancing hood over the
face of each Therma-Fuser diffuser and adjust damper
at duct takeoff to obtain maximum design air volume.
Appearance
If a velocity meter is used, measure discharge velocity
Panel
at the housing (See
Fig.
times A
of .12 f
to get air flow in cfm.
t
2
k
Page 2 of 6
BALANCING (TK-D)
Appearance
Panel
1.
The damper blade opening is factory set at 3/4
inch/19mm (See
turning the damper opening cam (See
2. Place a direct reading diffuser balancing hood over the
face of each TK-D diffuser and adjust damper at duct
takeoff to obtain design air volume. If a velocity meter
BALANCING (TK-D)
is used, measure discharge velocity at the housing (See
3). Multiply the velocity in fpm times A
Fig.
1.
The damper blade opening is factory set at 3/4
get air flow in cfm.
inch/19mm (See
Fig.
4). Readjust where necessary by
FIG. 4 MEASURING DAMPER BLADE OPENING
turning the damper opening cam (See
Fig 4. Measuring damper blade opening
2. Place a direct reading diffuser balancing hood over the
Foam
face of each TK-D diffuser and adjust damper at duct
takeoff to obtain design air volume. If a velocity meter
is used, measure discharge velocity at the housing (See
Blade
3). Multiply the velocity in fpm times A
Fig.
get air flow in cfm.
Fig 4. Measuring damper blade opening
ADJUSTING MINIMUM FLOW (TK-HC, TK-C)
Foam
Minimum flow is adjusted by turning the damper opening
cam until the damper blades are open the correct amount.
Determine the correct blade opening for the required percent
Blade
minimum flow from the graph in
opening as shown in
ADJUSTING MINIMUM FLOW (TK-HC, TK-C)
Fig 5. Percent Minimum Flow vs. Blade Opening
Minimum flow is adjusted by turning the damper opening
PERCENT of AIR FLOW CAPACITY vs. BLADE OPENING
cam until the damper blades are open the correct amount.
Determine the correct blade opening for the required percent
100
minimum flow from the graph in
opening as shown in
and adjust the damper opening cam.
Fig. 3
80
Fig 5. Percent Minimum Flow vs. Blade Opening
60
Diffusion
Damper
Housing
Diffusion
Probe
Damper
Housing
3). Multiply the velocity in fpm
Gauge
1250 to
2300 fpm
Probe
4). Readjust where necessary by
Fig.
Fig.
2).
Gauge
1250 to
2300 fpm
of .12 f
k
Fig.
2).
Housing
of .12 f
k
Small Steel Rule
Housing
5. Measure the blade
Fig.
and adjust the damper opening cam.
Fig. 3
Small Steel Rule
5. Measure the blade
Fig.
Panel
BALANCING (TK-D)
1.
The damper blade ope
inch/19mm (See
Fig. 4
turning the damper op
2. Place a direct reading
face of each TK-D diffu
takeoff to obtain desig
is used, measure disch
3). Multiply the vel
Fig.
get air flow in cfm.
Fig 4. Measuring damper bl
Foam
Blade
ADJUSTING MINIM
Minimum flow is adjusted b
cam until the damper blad
Determine the correct blad
minimum flow from the gra
opening as shown in
Fig. 3
Fig 5. Percent Minimum Flo
PERCENT of AIR FLOW CA
100
80
60
40
20
0
0
.10
.20
.30
(0)
(2.5)
(5.1)
(7.6)
Figure 7 @ 200%
BLADE OPE
Figure 7 @ 200%
to
t
2
to
t
2
3
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