Honeywell NK300 Installation Instructions Manual Download Page 6

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Honeywell GmbH

MU1H-1556GE23 R1114

1. Safety Guidelines

1. Follow the installation instructions.
2. Use the appliance

• according to its intended use
• in good condition
• with due regard to safety and risk of danger.

3. Note that the appliance is exclusively for use in the

applications detailed in these installation instructions. Any
other use will not be considered to comply with
requirements and would invalidate the warranty.

4. Please take note that any assembly, commissioning,

servicing and adjustment work may only be carried out by
authorized persons.

5. Immediately rectify any malfunctions which may influence

safety.

2. Description of function

The refilling combination combines backflow preventer,
pressure reducing valve and ball valves in one appliance.

Function backflow preventer

The backflow preventer is a safety device in accordance with
EN 1717 to protect the quality of potable water against back
pressure, back flow and back syphonage of non-potable
water from plants and connected equipment..
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 check valves and the discharge valve are
closed.
If water is drawn from the downstream system, the backflow
preventer is in flow position. The check valves up- and
downstream are opened and the discharge valve is closed.
The backflow preventer changes to shut-off position (back
pressure) if the differential pressure between middle- and
inlet chamber falls under 0.14 bar. The check valves are
closed and the discharge valve is opened.

Function pressure reducing valve

The pressure reducing valve reduces the inlet pressure to the
desired set-pressure on the outlet side.
The pressure reducing valve works according to the force
comparison 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 has no influence on the regulation of the
pressure reducing valve. Inlet pressure fluctuation does not
influence the outlet pressure, thus providing inlet pressure
balancing.
The refilling combination can be connected in accordance to
DIN EN 1717 constantly by hose line or piping. (KTW

approval for hose line neccessary).
In order to prevent an uncontrolled refill of the heating system,
the shut off valvemust be closed after the filling procedure..

3. Application

4. Technical data

5. Scope of delivery

The refilling combination consists of:
• Shut off valve, up- and downstream
• Complete backflow preventer with discharge connection,

valve cartridge (incl. integrated check valve and discharge
valve, upstream), integrated strainer upstream (mesh size
approx. 0.2 mm), check valve downstream and three test
points

• Complete pressure reducing valve with valve insert (incl.

diaphragm and valve seat), spring bonnet (incl. adjustment
screw), adjustment spring and pressure gauge

6. Options

7. Assembly

7.1. Installations Guidelines

It is necessary during installation to follow the installation
instructions, to comply with local requirements and to follow
the codes of good practice.
• Install in horizontal pipework with discharge connection

directed downwards

• 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 environment should be protected against

frost and ventilated well

• The installation location has to be easily accessible

- Simplified maintenance and cleaning
- Pressure gauge at the pressure reducing valve can be

read off easily

Medium

Water

Inlet pressure

min. 2.0 bar
max. 10.0 bar