Honeywell NK298S Product specification sheet
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V
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Construction
The refilling combination consists of:
• Ball valve, up- and downstream
• Complete backflow preventer with discharge connection,
valve cartridge (incl. integrated non return valve and discharge valve, upstream), integrated strainer upstream (mesh size
approx. 0,5 mm), non return valve downstream and three ball
valves with closing cap
• Complete pressure reducing valve with valve insert (incl. diaphragm and valve seat), spring hood (incl. adjustment screw),
adjustment spring, filter bowl, fine filter (mesh size approx.
0,16 mm) and manometer
Materials
• Housing in red-bronze or dezincification-resistant brass
• Discharge connection, valve cartridge, valve insert, spring
hood and filter bowl in high-grade synthetic material
• Ball valves in dezincification-resistant brass
• Fibre-reinforced NBR diaphragm
• Seals in NBR and EPDM
• Spring steel adjustment spring
• Stainless steel fine filter mesh
EN0H-1229GE23 R0905 y Subject to change without notice
NK298S
Refilling combination
Product specification sheet
Application
The refilling combination serves automatic filling and refilling from
closed heating systems to DIN EN 12828:2003.
The refilling combination can be connected in accordance to DIN
EN 1717 constantly with the drinking water supply.
The refilling combination combines backflow preventer, pressure
reducing valve and ball valve in one appliance.
The refilling combination contains all devices for refilling a heating
installation, according to conforming standards.
Special Features
• All components DIN/DVGW approved
• Constant connection with the drinking water supply in accordance with DIN EN1717 by hose line or piping are possible
• Corrosion resistant by use of red-bronze, brass and stainless
steel
• Low flow resistance and high rate of flow
• Optimal protection of the drinking water supply
• Backflow preventer sound insulation, class 2
• Pressure reducing valve sound insulation, class 1
• Backflow preventer offers threefold security - two non return
valve and a discharge valve separate the backflow preventer
into three chambers
• Field-tested reliable pressure reducing valve
• Pressure reducing valve with inlet pressure balancing - inlet
pressure fluctuation does not influence the outlet pressure
• Outlet pressure adjustable and directly at the manometer
readable
• Reliable and proven
• Low maintenance effort - cartridge insert and valve insert are
completely replaceable
• Filter bowl at the pressure reducing valve in clear synthetic
• Complies with KTW requirements
Range of Application
Medium Water
Inlet pressure min. 1.5 bar
max. 10.0 bar
Outlet pressure 1.5-6 bar adjustable
Liquid category
Backflow Preventer
Technical Data
Installation position horizontal pipework with discharge
Operating temperature max. 65 °C
Minimum pressure drop 1 bar
Connection ball valve
Backflow preventer
Connection size
Discharge
Connection size
4 (toxic, highly toxic, tumourigenic,
radioactive materials)
connection directed downwards
1
G
/4"
HT 50
1
/2" AG
www.honeywell.com 1
NK298S Refilling combination
ø
50mm
l
2
L
Connection size R
Weight approx. kg 2.8
Dimensions mm
l
1
1
H222
h
1
h
2
138
L404
l
1
l
2
140
/2"
80
90
Method of Operation
The refilling combination combines backflow preventer, pressure
reducing valve and ball valve in one appliance.
The backflow preventer is a safety device in accordance with
DIN EN 1717 to protect systems against back pressure, back
flow and back syphonage of non-potable water into service pipe,
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1
plants and equipments.
The backflow preventer is separated in three chambers (inlet,
middle and outlet chamber).
If no water is drawn from the downstream system, the backflow
preventer is in normal position. The up- and downstream non re-
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2
turn valves and the discharge valve are closed.
If water is drawn from the downstream system, the backflow preventer is in flow position. The non return valves up- and downstream are opened and the discharge valve is closed.
The backflow preventer change to shut-off position (back pressure) if the differential pressure between middle- and inlet chamber falls under 0.14 bar. The upstream non return valve is closed
and the discharge valve is opened.
The pressure reducing valve reduces the pressure on the inlet
side (admission pressure) to the level of the desired pressure on
the outlet side (outlet pressure) in individual cases.
The pressure reducing valve functions on a force equalisation
principle. The force of a diaphragm operates against the spring
force of the regulating valve. If the outlet pressure and therefore
diaphragm force fall because water is drawn, then the greater
force of the spring causes the valve to open. The outlet pressure
then increases until the forces between the diaphragm and the
spring are equal again.
The inlet pressure (admission pressure) has no influence on the
regulating valve of the pressure reducing valve. Inlet pressure
fluctuation does not influence the outlet pressure, thus providing
inlet pressure balancing.
TK295
ZR06K
Bar
45
6
3
7
2
1
P
100
150
50
bar
0
200
TKA295
Options
NK298S-1/2A= Standard version with threaded connection
1
R
/2"
Accessories
TK295 Test kit
Electronic pressure measuring device with digital indi-
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9
10
cator, runs by a battery.
With case and accessories, ideal for inspection and
maintenance of backflow preventer type BA.
TKA295 Test kit
Analogue pressure measuring device with differential
pressure display.
With case and accessories, ideal for inspection and
maintenance of backflow preventer type BA.
ZR06K Double ring spanner
For removal of spring hood and filter bowl
EN0H-1229GE23 R0905 y Subject to change without notice
2 www.honeywell.com
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