Data sheet
Pressure operated water valve
Type WVO
Pressure operated water valve type WVO is used
for regulating the flow of water in refrigeration
plant with water-cooled condensers.
The pressure operated water valve gives
modulating regulation of the condensing
pressure and so keeps it constant during
operation. When the refrigeration plant is
stopped, the cooling water flow is shut off
automatically.
Pressure operated water valve can be used with
flammable refrigerants. Double sealing between
the refrigerant and the water line ensures that
in case the bellows damage and the refrigerant
leak, it cannot enter into the water. This severely
limits the safety implications.
It means that the valve can be used together with
a double walled heat exchanger and water circuit
in such a system does not need to be considered
as a part of the installation for flammable
refrigerants (EN378-1:2008, clause 4.4.2.2).
Features
y Compact valve
y Setting pressure done by factory (optional)
y HCFC, HFC and HC
y NPT threads on request
y Capillary tube available as option
y Stainless steel version available for request
y Suitable for flammable refrigerants
y May be used in the following EX range:
Category 3 (Zone 2)
© Danfoss | DCS (az) | 2018.03
DKRCC.PD.DA0.B8.02 | 1
Data sheet | Pressure operated water valve, type WVO
Technical data
Water side Refrigerant side
Max. working pressure PS / MWP 16 bar / 232 psig 26.4 bar / 383 psig
Max. test pressure PT 24 bar / 350 psig 38 bar / 551 psig
R22, R1270, R134a, R290, R404A,
Media Fresh water and neutral brine
R407A, R407C, R407F, R448A, R449A,
R450A, R452A, R507A, R513A, R600,
R600a
Max. differential pressure 10 bar / 145 psi –
Temperature range -25 – 130 °C / -13 – 266 °F -25 – 130 °C / -13 – 266 °F
1
Typ e
[mm] [in] [m³ / h] [gal / min]
WVO 10 LF 10
WVO 10 10
WVO 15 15
WVO 20 20
Orifice size kv value
2
5
/
2
5
/
3
5
/
4
5
/
)
Cv value
0.63 0.7
1.4 1.6
1.9 2.2
3.4 3.9
WVO 25 25 1 5.5 6.4
1
The kv value is the flow of water in [m3 / h] at a pressure drop across valve of 1 bar, ρ = 1000 kg / m
2
The Cv value is the flow of water in [gal / min] at a pressure drop across valve of 1 psi, ρ = 10 lbs / gal
3
2
)
Capacity The capacity curves show the capacities of
the individual valves (water quantity in [m3 / h])
depending on the water pressure drop across the
valve.
SI unit US unit
[bar]
The capacity given apply at 85% valve opening
and are obtained with the offset shown on
page 4.
[bar]
© Danfoss | DCS (az) | 2018.03
[m3 / h]
[gal / min]
DKRCC.PD.DA0.B8.02 | 2
Data sheet | Pressure operated water valve, type WVO
Ordering
Typ e
Connection
type
WVO 10 LF G 3/
WVO 10 LF G 3/
WVO 10 G 3/
WVO 10 G 3/
WVO 10 G 3/
WVO 10 G 3/
WVO 15 G 1/
WVO 20 G 3/
Connection
standard
8
8
8
8
8
8
2
4
ISO 228–1 8 – 12 115 – 175 003N8053
ISO 228–1 14 – 18 200 – 260 003N8054
ISO 228–1 8 – 12 115 – 175 003N5203
ISO 228–1 14 – 18 200 – 260 003N5206
ISO 228–1 16 – 20 232 – 290 003N5207
ISO 228–1 16 – 22 232 – 320 003N6220
ISO 228–1 Available on request
ISO 228–1 Available on request
Pressure range
[bar] [psig]
Code no.
WVO 25 G 1 ISO 228–1 Available on request
WVO 10 NPT 3/
WVO 10 NPT 3/
WVO 15 NPT 1/
WVO 15 NPT 1/
WVO 20 NPT 3/
8
ANSI/ASME B1.20.1 6 – 10 85 – 145 003N8052
8
ANSI/ASME B1.20.1 14 – 18 200 – 260 003N8056
2
ANSI/ASME B1.20.1 6 – 10 85 – 145 003N8062
2
ANSI/ASME B1.20.1 14 – 18 200 – 260 003N8066
4
ANSI/ASME B1.20.1 14 – 18 200 – 260 003N8076
WVO 25 NPT 1 ANSI/ASME B1.20.1 Available on request
) with 0.8 m capillary tube and valve opener
) WVO 10 low flow version with kv value: 0,63 m³⁄h
Codes for valve with prefabricated factory setting, other sizes and pressure ranges are available on
request.
2
)
2
)
1
)
Accessories
Description Code no.
1 m (39 in) capillary tube ¼ in. (6 mm) flare coupling nuts at each end 060- 007166
Bracket 003N0388
© Danfoss | DCS (az) | 2018.03
DKRCC.PD.DA0.B8.02 | 3
Data sheet | Pressure operated water valve, type WVO
Sizing When sizing and selecting water regulating
valves it is most important to ensure that the
valve at any time is able to give the necessary
quantity of cooling water.
To select a suitable size of valve it is necessary
to know the precise amount of cooling required.
On the other hand, to avoid the risk of unstable
regulation (hunting) the valve should not
be oversized. In general, the aim should be
to select the smallest valve capable of giving
the required flow .
To obtain a precise control it can be
recommended to only use 85% of the capacity.
Offset
Water Capacity
Below 85% the ratio between flow and
condensing difference pressure is linear. Above
85% the ratio is no longer linear. To reach a 100%
capacity the WVO needs significant increase of
condensing pressure. See table at the bottom of
the page.
Valve size
offset
∆p
Typ e
WVO 10 LF 1.6 23
WVO 10 2.0 30
WVO 15 2.5 35
WVO 20 3.0 43
WVO 25 3.5 50
[bar] [psi]
∆p offset
The following data is used when selecting
the size of WVO:
y Cooling capacity of condenser,
y Temperature rise in cooling media,
y Differential pressure across valve,
y Condensing temperature,
y Specific heat capacity of cooling media,
y Refrigerant.
Condensing
pressure
© Danfoss | DCS (az) | 2018.03
DKRCC.PD.DA0.B8.02 | 4
Data sheet | Pressure operated water valve, type WVO
Calculating size in SI Unit Example 1:
y Condenser capacity Q0: 30 kW
y Condensing temperature t0: 35 °C
y Refrigerant: R404A
y Cooling media: water
Necessary mass flow
Volume flow
Selecting size
∆p [bar]
y Specific heat capacity of water
Cp: 4.19 kj / (kg*K)
y Water inlet temperature t1: 15 °C
y Water outlet temperature t2: 25 °C
y Pressure drop across valve p: max. 1.0 bar
Q
·
m =
c
· 3600 =
30
Cp · (t2 t1) 4.19 · (25 - 15)
·
·
m = 2577
V =
≈ 2.6 m3 / h
ρ 1000
· 3600 = 2577 kg / h
© Danfoss | DCS (az) | 2018.03
[m3 / h]
Selecting WVO 20 code number
The saturated pressure for R404A
Tc = 35 °C Pc = 7.9 barg
Choose a WVO 20 with 6 – 10 barg range
DKRCC.PD.DA0.B8.02 | 5
Data sheet | Pressure operated water valve, type WVO
Calculating size in SI Unit
(continue)
Example 2:
y Condenser capacity Qc: 20 kW
y Condensing temperature tc : 35 °C
y Refrigerant: R134a
y Cooling media: Brine
y Density of brine ρ: 1015 kg / m
Necessary mass flow
Volume flow
kv value
Selecting size of WVO 20
y Specific heat capacity of brine
Cp : 4.35 kj (kg*K)
y Brine inlet temperature t1: 20 °C
y Brine outlet temperature t2: 25 °C
y Pressure drop across valve p: max. 2.0 bar
3
Q
·
m =
c
· 3600 =
Cp · (t2 t1) 4.35 · (25 - 20)
·
·
m = 3310
V =
≈ 3.26 m3 / h
ρ 1015
·
kv ≥
V
3.26
=
1000 · p 1000 · 2.0
ρ 1015
Code number
20
· 3600 = 3310 kg / h
= 2,32 m3 / h
kv ≥ 2.32 m3 / h WVO 20
WVO 20 has kv = 3.4 m3 / h and the necessary
capacity is below 85% of full capacity.
The saturated pressure for 134a
T
= 35 °C Pc = 7.9 barg
c
Choose a WVO 20 with 6 – 10 barg range
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Data sheet | Pressure operated water valve, type WVO
Calculating size in US Unit
Example 1:
y Condenser capacity Qc: 5 TR
y Condensing temperature tc: 95 °F
y Refrigerant: R404A
y Cooling media: water
Necessary water flow
Selecting size
V =
500 (t2 - t1) 500 · (75 - 60)
∆p [psi]
y Water inlet temperature t1: 60 °F
y Water outlet temperature t2: 75 °F
y Pressure drop across valve p: max. 15 psi
Qc 15000 = 5 15000
= 10 GPM
© Danfoss | DCS (az) | 2018.03
[gal / min]
Selecting WVO 20 code number
The saturated pressure for R404A
Tc = 95 °F PC = 115 psig
Choose a WVO 20 with 85 – 145 psig range
DKRCC.PD.DA0.B8.02 | 7
Data sheet | Pressure operated water valve, type WVO
Design / Function
1. Screw for setting pressure
2. Spring housing
3. Spindle retainer
4. Spring retainer
5. O-ring
6. Guide bush
7. Diaphragm
8. Valve plate
9. Thrust pad
10. Bellows element
Installation
Condensing pressure impulses are transmitted
via the bellows element to the valve cone so that
the valve - even at very small pressure variations is able to adapt the quantity of water required by
the condenser.
If fluorinated refrigerants are to be used
a capillary tube connection is required, 1 m
capillary tube with ¼ in. / 6 mm flared union nuts
at either end can be supplied.
The valves are pressure-relieved in such a way
that a variation in the water pressure will not
affect their setting.
To protect the refrigeration plant against high
head pressures - in the event that the water
supply to the condenser should fail - a safety
switch type KP or RT should be fitted on the high
pressure side.
Between the flare connection of the pressure
operated water valve and the pipe
line / compressor Danfoss recommends to use
capillary tube to avoid fatigue error due to the
vibration from the compressor.
The valve plate (8) is a brass plate with
a vulcanized layer of special rubber to form
an elastic seal against the valve seat. The valve
is externally sealed by the diaphragms (7).
The top and bottom of the valve plate holder
is extended by a guide that is fitted with
O-rings (5) to ensure the internal operating
parts move correctly. These O-rings, fitted in
conjunction with the diaphragms, also provide
extra protection against external leakage.
The valve seat is made of stainless steel and
is swaged to the valve body.
The installation of an MESH 40 filter ahead of the
valve is recommended.
If a mounting bracket is used it must always be
between valve body and setting section.
© Danfoss | DCS (az) | 2018.03
DKRCC.PD.DA0.B8.02 | 8
Dimensions and weights
Bracket
15
22
9
56
50
40
Ø4
Ø7.15
25
62
Danfoss
3N200.11
Typ e
H
1
[mm] [in] [mm] [in] [mm] [in] [mm] [in] [kg] [lbs]
H
2
L L
1
Net weight
WVO 10 91 3.58 89 3.50 72 2.83 11 0.43 1. 0 2.20
WVO 15 91 3.58 89 3.50 72 2.83 14 0.55 1.0 2.20
WVO 20 91 3.58 89 3.50 90 3.54 16 0.63 2.0 4.40
WVO 25 96 3.78 94 3.70 96 3.74 19 0.75 2.0 4.40
© Danfoss | DCS (az) | 2018.03
DKRCC.PD.DA0.B8.02 | 9
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