Danfoss FJVA Data sheet
Data Sheet
Thermostatic operated water valve
Type FJVA
With built-in temperature sensor
Thermostatic operated water valves are used
for the innite, proportional regulation of ow
quantity, depending on the setting and the
sensor temperature.
The Danfoss range of thermostatic operated
water valves includes a series of industrial
products for both cooling and heating
regulation. The valves are self-acting, i.e. they
operate without the supply of auxiliary energy
such as electricity or compressed air.
Because the valves constantly match ow
quantity to demand they are especially suitable
for temperature regulation.
The required temperature is maintained
constant with no overconsumption of:
• Cooling water in cooling systems; hot water
or steam in heating systems
• Thus operating economy is always reasonable
Features:
• Self-acting thermostatic operated water
valve, which operates without auxiliary
energy
• Opens on rising temperature of cooling water
• Valve opening degree is not aected by
cooling water pressure dierential
• Hand regulation - unique option on the
market, which saves installation time
• Regulating range dened for the point at
which the valve begins to open
AI155286424361en-000401
Setting section with knob,
reference spring and setting scale.
Valve body with orice,
closing cone and sealing elements.
Sensor in hermetically
sealed thermostatic element.
Danfoss
3N1101
Danfoss
3N1447
Danfoss
3N1446
Danfoss
3N1447
Thermostatic operated water valve, Type FJVA
Functions
How it works?
When the three elements are built together and the valve is installed, the function sequence is as follows:
1.
A temperature-dependent pressure - charge vapour pressure - builds up in the sensor.
2.
This pressure is transferred to the valve via the bellows and acts as an opening or closing force.
3.
The knob on the setting section and the spring exert a force that acts counter to the bellows.
4.
When balance is created between the two opposing forces, the valve spindle remains in its position.
5.
If the sensor temperature - or the setting - is changed, the point of balance becomes displaced and the valve
spindle moves until balance is re-established, or the valve is fully open or closed.
6.
On sensor temperature change the ow quantity change is approximately proportional.
7.
The illustrations show an FJVA cooling water valve, but the function principle applies to all types of thermostatic
valves.
Table 1: FJVA valves consist of three main elements
Applications
FJVA valves are for applications where, because of installation problems, etc., it is desirable to avoid using a capillary
tube. This applies mainly where regulation accuracy requirements are more moderate and where an integral bypass
can be accepted.
In FJVA the whole bellows element is used as the sensor. The valve reacts to the cooling water temperature and
therefore it must always be installed in the return line. Thus, indirect regulation is involved.
To ensure the medium temperature to inuence the thermostatic element, when the valve is closed, a by-pass in the
valve (see Figure 1: Valve body with by-pass) provides a constant minimal ow through the valve.
Figure 1: Valve body with by-pass
Valves of this type operate with signicantly longer time constants than AVTA valves where the sensor is located at
the point at which the temperature is to be regulated. FJVA is mainly used in systems where large and sudden load
changes do not occur.
© Danfoss | Climate Solutions | 2021.03 AI155286424361en-000401 | 2
1
2
4
3
5
2
Danfoss
3N554
No.
Description
Material
1
Spindle
Brass2Diaphragms
Rubber - ethylene - propylene (EPDM)
3
Valve body and other metal parts
Forged brass
4
Valve cone
Nitrile rubber (NBR)
5
Valve seat
Stainless steel
Danfoss
3N554
Thermostatic operated water valve, Type FJVA
Product specication
Materials
Figure 2: Materials connected with FJVA
Table 2: Materials - parts in contact with the medium
Installation
Figure 3: FJVA installation
The valves can be installed in any position. An arrow on the valve body indicates the direction of ow. FJVA valves
are also marked so that the letters RA can be read straightforwardly. The installation of an FV lter ahead of the valve
is recommended.
If a mounting bracket is used - see Spare parts and accessories - it must always be between valve body and setting
section (see illustration).
© Danfoss | Climate Solutions | 2021.03 AI155286424361en-000401 | 3
Loading...