Danfoss STV, STVL, STVA, STVC Data sheet

Data sheet STV Series

Balancing Valves

Applications/
Features:

Ordering
Information:

STV / STVL

Danfoss STV series of balancing valves provide
testing and balancing of circuit flow for hydronic
heating or cooling systems.

STV valves provide a high level of balancing
accuracy using an easy to set multi-turn setting
wheel and memory lock.

Valve Size

1/2” 1.2 (0.5) 4.1 065F8965 065F896501

3/4” 1.3 (0.6) 5.9 065F8966 065F896601

STV /
STVL

1” 1.7 (0.8) 10.2 065F8967 065F896701

1-1/4” 2.7 (1.2) 15.2 065F8968 065F896801

1-1/2” 3.3 (1.5) 22.6 065F8969 065F896901

2” 5.1 (2.3) 36.5 065F8970 065F897001

Weight

lbs. (kg)

STVA / STVC

Features:

Positive shut-off•
Built-in memory stop•
Multi-turn 360 hand wheel with vernier scale •

and digit readout

Offset pressure/ temperature ports•
Presetting and locking with Allen key•

Cv*

NPT (STV) F. Solder (STVL)

Connection

Valve Size

2-1/2” 31 (14) 110

3” 45 (20) 128 065F8972

STVA

STVC

*Cv= Flow rate in GPM with a pressure drop of 1 psi.

4” 58 (26) 222 065F8973

5” 90 (41) 350 065F8974

6” 112 (51) 495 065F8975

8” 275 (125) 696 065F8993

10” 490 (222) 1405 065F8994

12” 573 (260) 1764 065F8995

VDDNB122 © Danfoss 05/08

Weight

lbs. (kg)

Cv* Connection Code No.

065F8971

ANSI

class 125

Flanged

1

Data sheet STV Series

Balancing Valves

Accessories:

Technical Specifications:

Part Description Code No.

Test Plug

Gauge Adapter Measuring
Needle

Replacement hand wheel

Max. static pressure:

Temperature range :

Connection:

Red Tag 065F8985

Blue Tag 065F8986

1/2” to 2” valves
(1/16” diameter, 1.75” length)

2-1/2” to 12” valves
(1/8” diameter, 1.75” length)

003Z40324

003Z0326

Hand wheel, 1/2” to 2” 900693

Hand wheel, 2-1/2” to 6” 900694

1/2” to 2” : 290 psi (20 bar)
2-1/2” to 12” : 232 psi (16 bar)

1/2” to 2”: -4° to 250°F (-20° to 120°C)
2-1/2” to 12”: 14° to 250°F (-10° to 120°C)

Female NPT and Female Solder (STV / STVL)
ANSI 125 Flanged (STVA / STVC)

Pressure tappings: P/T plugs

Allowable fluid Closed loop application, 100% water, max 50% glycol mixture

System Layout:

STVA / STVC

STV / STVL

STV / STVL

STV / STVL

STV / STVL

Copper Fin

Radiator

Fan Coil

Unit

STVA / STVC

Fan Coil

Unit

Fan Coil

Unit

STVA / STVC

M

M

M

M

M

STV / STVL

Chiller or

Boiler

VDDNB122 © Danfoss 05/08

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Data sheet STV Series

Balancing Valves

Installation:

Setting Flow Coefficient
values
(Cv value = gpm@1psi ∆P):

Install the balancing valve with the arrow on the
valve’s body pointing in the direction of the flow
in the system.

To ensure an accurate reading, a straight length
of 5 times the diameter of the pipe should be
piped prior to the valve and a straight length
of at least 2 times the pipe diameter should be
piped after the valve.

If a pump is installed near the valve, a straight
length of 10 times the diameter of the pipe
should be piped prior to the valve to reduce an
inaccurate measurement due to turbulence.

STV /
STVL

Size 1 2 3 4 5 6 7 8 9 10

1/2” 0.21 0.37 0.52 0.72 1.00 1.36 1.88 2.96 3.65 4.12

3/4” 0.39 0.70 0.96 1.31 1.80 2.44 3.36 4.47 5.22 5.92

1” 0.56 0.89 1.19 1.74 2.67 4.18 5.80 7.54 9.16 10.20

1-1/4” 0.92 1.53 2.09 3.13 4.76 6.84 9.05 11.30 13.30 15.20

1-1/2” 1.39 2.38 3.25 4.76 7.19 10.3 13.90 17.10 19.80 22.60

2” 2.32 4.18 6.03 8.82 13.80 19.4 24.60 29.00 33.20 36.50

Number of Turns

Cv Values

STVA Number of Turns

Size 1 2 3 4 5 6 7 8 9 10

2-1/2” 3.2 5.9 11.1 23.2 41.2 59.2 76.6 91.1 101.0 108.0

3” 6.4 11.0 15.7 21.5 34.2 56.8 79.5 98.6 114.0 128.0

4” 9.3 15.7 22.0 38.3 77.7 115.0 145.0 174.0 197.0 220.0

5” 11.6 25.5 38.3 73.1 123.0 174.0 225.0 274.0 317.0 349.0

6” 20.9 38.3 78.9 151.0 216.0 285.0 341.0 394.0 447.0 493.0

STVC Number of Turns

Size 2 3 4 5 6 7 8 9 10 11 12 14 16 18

8”

10”

12”

Based upon the flow or differential pressures
required within the system, the flow can be
determined by using the equation:

Q = flow



Cv= flow coefficient

∆p

= differential pressure

46 66

116 160

116 180

Q = C

v

84 139 215 290 365 452 545 638 696 - - -

204 349 494 689 884 1031 1177 1291 1405 - - -

244 396 546 708 869 1012 1153 1290 1427 1588 1668 1764

For correction of fluids other than water,
the following equation applies provided
the viscosity of the fluid is the same for

_____

.

∆p

√

water, which is the case for most glycol and
brine solutions:

Q

M

___

=

Q

R



√

Q

= real flow

R

Q

= measured flow

M

 = specific density of fluid

Cv Values

Cv Values

VDDNB122 © Danfoss 05/08

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Data sheet STV Series

Balancing Valves

Flow Rate Graphs:

1 foot of head (FOH) = 0.434 psi

1. Plot the required flow rate
and pressure drop within the
columns and then draw a
line between these plotted
points.

2. Draw an additional
horizontal line from the
intersection of the Cv
column across the valve
sizes.

3. Based upon the intersection
of the horizontal line with
the valves sizes, select the
appropriate sized valve.

In selecting the valve, a margin
of allowance for adjustment
should be considered if during
commissioning the pressure
drop is lower than designed.
This reduced pressure drop may
result in an undersized valve.

STV/STVL Balancing Valves 1/2” - 2”

Flow Rate Cv / K

v

Number of Turns

Opened

Pressure Drop

The selection of a valve that has
a pre-set value above 3 turns
offers better accuracy when
setting.

Valve Size

Selection example:

Required- 8.73 GPM (0.55 l/s) at a pressure drop of 3.35 FOH (10kPa)

Potential sizes, 1”, 1-1/4” or 1-1/2”.

VDDNB122 © Danfoss 05/08

4

Data sheet STV Series

Balancing Valves

Flow Rate Graphs:

1 foot of head (FOH) = 0.434 psi

1. Plot the required flow rate
and pressure drop within the
columns and then draw a
line between these plotted
points.

2. Draw an additional
horizontal line from the
intersection of the Cv
column across the valve
sizes.

3. Based upon the intersection
of the horizontal line with
the valves sizes, select the
appropriate sized valve.

In selecting the valve, a margin
of allowance for adjustment
should be considered if during
commissioning the pressure
drop is lower than designed.
This reduced pressure drop may
result in an undersized valve.

STVA Balancing Valves 2-1/2” - 6”

Flow Rate Cv / K

v

Number of Turns

Opened

Pressure Drop

The selection of a valve that has
a pre-set value above 3 turns
offers better accuracy when
setting.

Valve Size

Selection example:

Required- A flow rate of 222 GPM (14 l/s) and a pressure drop of 1.67 FOH (5 kPa)

The required balancing valve for this application is a 5” with a setting of 7.8 turns or a 6” with a
setting of 5.8 resulting in a Cv of 263 (Kv=225).

VDDNB122 © Danfoss 05/08

5

Data sheet STV Series

Balancing Valves

Flow Rate Graphs:

1 foot of head (FOH) = 0.434 psi

1. Plot the required flow rate
and pressure drop within the
columns and then draw a
line between these plotted
points.

2. Draw an additional
horizontal line from the
intersection of the Cv
column across the valve
sizes.

3. Based upon the intersection
of the horizontal line with
the valves sizes, select the
appropriate sized valve.

In selecting the valve, a margin
of allowance for adjustment
should be considered if during
commissioning the pressure
drop is lower than designed.
This reduced pressure drop may
result in an undersized valve.

The selection of a valve that has
a pre-set value above 3 turns
offers better accuracy when
setting.

STVA Balancing Valves 8” - 12”

Flow Rate Cv / K

v

Number of Turns

Opened

Pressure Drop

Valve Size

Selection example:

Required- A flow rate of 1,316 GPM (83 l/s) and a pressure drop of 16.73 FOH (50 kPa)

The balancing valve for this application could be an 8” valve set for 9.5 turns, a 10” valve set for 6
turns or a 12” valve set for 5.8 turns resulting in a Cv of 502 (Kv=430).

VDDNB122 © Danfoss 05/08

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Data sheet STV Series

Balancing Valves

Dimensions and
Construction:

C

B

A

STV Valve STVL Valve

STV / STVL

Size

A

in (mm)

B

in (mm)

in (mm)

1/2” 3.4 (86.4) 3.7 (93.9) 1.6 (40.6)

3/4” 3.5 (88.9) 3.7 (93.9) 1.7 (43.2)

1” 4.0 (104.1) 3.8 (96.5) 1.7 (43.2)

1-1/4” 4.7 (119.4) 3.8 (96.5) 1.9 (45.7)

1-1/2” 5.2 (132.1) 4.3 (109.2) 1.9 (45.7)

2”

(1)

STVL F.Solder version,

(153.9/164.1)

6.1/6.5

(2)

P/T Tap offset

4.4 (111.7) 2.1 (53.1)

(1)

C

B

A

Body and parts

(2)

C

in contact

with liquid

Dezincification
resistant brass

Gaskets: EPDM

Seat Seal: EPDM

Handwheel:

Polyamide
Plastic

STVA / STVC

Size L1

in (mm)

STVA

2-1/2” 11.4 (290.1) 8.9 (227.1)

H1

in (mm)

3” 12.2 (309.9) 9.5 (241.3)

4” 13.8 (350.0) 10.2 (259.1)

5” 15.8 (400.1) 11.7 (297.9)

6” 18.9 (480.1) 12.1 (306.1)

STVC

8” 23.6 (599.4) 20.1 (510.5)

10” 28.7 (729.9) 20.9 (530.9)

12” 33.5 (850.9) 24.0 (609.6)

STVA / STVC

Body and bonnet: Cast iron

Seat seal: PTFE

Gaskets: EPDM

Other metal parts: Brass

Hand wheel,
STV / STVL / STVA

Ploymide
Plastic

VDDNB122 © Danfoss 05/08

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Data sheet STV Series

Balancing Valves

Typical specification:

The balancing valve shall be of a brass
construction and have female national pipe
thread (NPT) or female solder connections. The
valve shall be suitable for heating or cooling
closed loop circuits. The balancing valve shall be
capable of positive shut off and have P/T plug
connections for testing. The valve adjustment
shall be done via hand wheel hand wheel with

digit readout within the handle of the valve. The
balancing valve shall a hidden memory feature
stop to prevent unauthorized adjustment and
to ensure a return to the preset position. The
memory stop within the valve shall be set via
inner stem of the valve to prevent tampering.
The valve shall be an STV series balancing valve.

Danfoss can accept no responsibility for possible errors in printed materials and reserves the right to alter its products without notice.
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Danfoss Inc.

6711 Mississauga Road, Suite 410
Mississauga, ON, L5N 2W3
Tel.: [phone], Fax: [phone]
www.na.heating.danfoss.com

VDDNB122 © Danfoss 05/08

Danfoss Inc.

7941 Corporate Drive
Baltimore, MD 21236 USA
Tel.: [phone], Fax: [phone]
www.na.heating.danfoss.com