Functional Description - Honeywell NK295C Mode D'emploi

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 instruc-
tions. Any other use will not be considered to comply
with requirements and would invalidate the
warranty.
4. Please take note that any assembly, commis-
sioning, servicing and adjustment work may only be
carried out by authorized persons.
5. Immediately rectify any malfunctions which may
influence safety.

2. Functional description

The refilling combination combines backflow
preventer, pressure reducing valve and ball valves in
one appliance.
The backflow preventer is a safety device in accor-
dance with EN 1717 to protect systems against back
pressure, back flow and back syphonage of non-
potable water into service pipe, plants and equip-
ments.
The backflow preventer is separated in three cham-
bers (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.
If the differential pressure between middle and inlet
chambers is less than 10 % of the inlet pressure, the
system disconnector moves into disconnect position
(back suction). The inlet side backflow preventer
closes and the discharge valve opens.
There is no possibility to control the safety function by
measuring.
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.
Spring-loaded pressure reducing valves work accor-
Honeywell GmbH
GB
ding to a system of force balance. The piston force
works against the spring force of the control valve. If
the outlet pressure (back pressure) drops as a conse-
quence of drawing water, leading to the piston force
dropping as well, the now greater spring force will open
the valve. The outlet pressure is higher again until the
balance between piston and spring force is once again
achieved.
The inlet pressure has no influence in either opening or
closing of the valve. Because of this, inlet pressure
fluctuation does not influence the outlet pressure, thus
providing inlet pressure balancing.
3. Application
Medium
Inlet pressure
Outlet pressure
Liquid category
Backflow Preventer
4. Technical data
Installation position
Operating temperature max. 65°C
Connection size
Discharge
Connection size
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. 0,5 mm) and
check valve downstream
• Complete pressure reducing valve with valve insert,
spring hood (including adjuster knob), setpoint
spring and pressure gauge
6. Assembly
6.1 Installations Guidelines
• Install in horizontal pipework with discharge connec-
tion 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 location must be ventilated well
• The installation location should be protected against
frost and be easily accessible
5
Water without inhibitors
min. 1.5 bar max. 10.0 bar
1.5-6 bar
3 (slightly toxic materials)
horizontal pipework with
discharge connection directed
downwards
HT 40
1/2" AG
MU1H-1548GE23 R0609