Danfoss NRVA Installation guide

Installation Guide

Check valves
NRVA

027R9531

027R9531

1

2

Type Bolt Nm LB-Feet

NRVA 15-20

NRVA 25-32

NRVA 40-50

NRVA 65

2 × M12

4 × M12

4 × M12

8 × M16

50 37

70 52

70 52

100 74

3

© Danfoss A/S (AC-MCI/MWA), 2013-10 DKRCI.PI.FK0.A2.02 / 520H4513 1

Installation

ENGLISH

Assembly

Remove welding debris and any dirt from
pipes and valve body before assembly.

Refrigerants

Applicable to HCFC, HFC and R717
(Ammonia).
Flammable hydrocarbons are not
recommended. The valve is only
recommended for use in closed circuits. For
further information please contact Danfoss.

Temperature range

NRVA: –50/+140°C (–58/+285°F)

Pressure range

NRVA: The valves are designed for a max.
working pressure of 40 bar g (580 psi g).

Installation

The valve must be installed in the flow
direction as indicated by the arrow on the
valve housing (fig. 1).
The valve is designed to withstand a high
internal pressure. However, the piping
system should be designed to avoid liquid
traps and reduce the risk of hydraulic
pressure caused by thermal expansion. It
must be ensured that the valve is protected
from pressure transients like “liquid
hammer” in the system.

Welding

The internal parts should be removed
before welding (fig. 2) to prevent damage
to the gaskets, as well as the teflon gasket
in the valve seat.
Only materials and welding methods,
compatible with the flange material, must
be welded to the flanges. The flanges
should be cleaned internally to remove
welding debris on completion of welding
and before the valve is reassembled.

Tightening

Thighten the staybolts and nut with a
torque wrench, to the values indicated in
the table (fig. 3).

Surface protection

The external surface of the flanges must be
prevented against corrosion with a suitable
protective coating after installation and
assembly.

Maintenance

Dismantling the valve

Do not remove the valve housing while the
valve is still under pressure.

- Check that the gasket has not been
damaged.

- Check that the cone is free of scratches
and impact marks.

- If the teflon cone ring has been
damaged, the whole cone assembly
must be replaced.

Assembly

Remove any dirt from the body before the
valve is assembled.

Tightening

Tighten the staybolts and nut with a torque
wrench, to the values indicated in the table
(fig. 3).

Use only original Danfoss parts, including
gaskets for replacement. Materials of
new parts are certified for the relevant
refrigerant.

Be careful not to damage the teflon on the
cone.

The valve inclusive flanges must be
free from stresses (external loads) after
installation.

The valves must not be mounted in
systems where the outlet side of the valve
is open to atmosphere. Both the inlet
and outlet side of the valve must always
be connected to the system or properly
capped off, for example with a welded-on
end plate.

2 DKRCI.PI.FK0.A2.02 / 520H4513 © Danfoss A/S (AC-MCI/MWA), 2013-10

In cases of doubt, please contact Danfoss.
Danfoss accepts no responsibility for
errors and omissions. Danfoss Industrial
Refrigeration reserves the right to make
changes to products and specifications
without prior notice.