Honeywell NK298S Product specification sheet

D

V

G

N

T

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,

h

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-

h

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-

8

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

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2 www.honeywell.com

Installation Example

NK298S Refilling combination

2

1

3

bar

0

4

Installation Guidelines

• Install in horizontal pipework with discharge connection di­rected downwards

• The installation is independent of the highest possible water
level

• The installation may not take place in areas or ducts where
poisonous gases or vapours may be present or where floo­ding can occur

• The installation location must be ventilated well

• The installation location should be protected against frost
and be easily accessible

o Simplified maintenance and cleaning.
o Manometer at the pressure reducing valve can be read off

easily

o Degree of contaminationin the filter bowl can be well obser-

ved

• Provide a straight section of pipework of at least five times the
nominal valve size after the pressure reducing valve (in accor­dance with DIN 1988, Part 5)

• The refilling combination has an integrated strainer - no sepa­rate strainer necessary

o Refilling combination is protected against malfunction and

corrosion damage resulting from ingress of foreign bodies,
e.g. welding beads, sealing materials, metal cuttings and
rust

Typical Applications

The refilling combination is priority suitable for domestic drinking
water supply.

The refilling combination can be used for commercial and indu­strial applications in consideration of its specifications.

Below two typical applications:

• Automatic refilling of the heating system

• Automatic refilling of systems up to liquid category 4 in accor­dance with DIN EN 1717.

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NK298S Refilling combination

1

9

4

Spare Parts

Refilling combination NK298S, from 2005 onwards

No. Description Dimension Part No.

Cartride insert

c

3

/4" 0903733

complete

Non return valve

d

3

/4" 0903735

complete

2

Replacement valve 1/2" + 3/4"D06FA-1/2

e

set (not incl. filter)

Sealing set

f

1

/2" 0901443

(10 pieces)

Blanking plug all S06K-1/4

g

1

with O-ring R

4

(5 pcs.)

Replacement filter in-

h

/4"

1

/2" + 3/4"ES06F-1/2A

sert

O-ring set

i

Filter bowl

j

Ball valve

k

Manometer 0 - 4 bar M07M-A4

l

1

/2" + 3/4" 0901246

1

/2" + 3/4"SK06T-1/2

1

/2" 2192900

9

3

5

4

3

10

6

7

8

Automation and Control Solutions

Honeywell GmbH
Hardhofweg
D-74821 Mosbach
Phone: [phone]
Fax: [phone]
http://europe.hbc.honeywell.com
www.honeywell.com

Manufactured for and on behalf of the
Environment and Combustion Controls Division of
Honeywell Technologies Sàrl, Ecublens, Route du
Bois 37, Switzerland by its Authorised
Representative Honeywell GmbH

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Subject to change
© 2005 Honeywell GmbH