Danfoss RT 280A Instructions página 2

Fig. 1
ENGLISH
Safety cut-out
Liquid level control
Technical data
1. General
Function ranges for RT 280A:
R 12 –50°C to +10°C
R 22, R 717 –50°C to 0°C
R 502 –65°C to –5°C
Function range for RT 281 A:
R 22 R 502, R 717 –30°C to +20°C
Liquid level differential: max. ±20 mm at max. func-
tion temp. and level change rate less then approx.
40 mm/minute.
Ambient temperature: –50°C to +70°C (–50T70).
Enclosure: IP 66 to IEC 529.
Contact load: See switch cover or fig. 5.
The marking, e.g. 10(4) A, 400 V ~ means that max.
connection current is 10 A ohmic or 4 A inductive at
400 V ~.
The max. starting current on motor cutin (L.R.) may
be up to seven times the inductive load – but max.
28A.
RTcomplies with conditions specified in VDE* 0660.
VDE* = Verband Deutscher Elektrotechniker
2. Power element
Adsorption charge
3 m capillary tube
Max. permissible bulb temperature: + 100°C
3. Heat-sensing element
Electric heater 10 W for 24 V d. c. and a.c.
1.5 m cable.
4. Pressure element
BSP with Æ6.5/Æ10 mm
3
Pressure connection: /
8
weld nipple.
Max. working pressure, PB/MWP: 22 bar/315 psig
Max. test pressure, p': 25 bar/355 psig.
Fig. 2
Fig. 3
Fitting. See figs. 2, 3, and 4.
Use the mounting holes 25.
The weld bushing should be mounted vertically so
that the lower edge of the bulb is at the same heights
as the max. permissible liquid level (fig. 2) or, when
used as a liquid level control, at the same height as
the liquid level required (fig. 3).
The electric bulb heater should be connected to 24
V d.c. or a.c. When 24 V d.c. or a.c. is not available
it will, therefore, be necessary to use a transformer.
Important: The electric bulb heater must be
constantly cut in when the current supply to the
system is on.
To start up the system after standstill, it is
recommended that the electric heater should be cut
in for a few minutes before starting the refrigeration
compressor.
If the evaporating temperature – and with it the
reference pressure – is greater than the max. range
temperature, RT units wilI register this as if the Iiquid
level were too high.
The pressure element should be connected in such
a way that the element pressure (reference pressure)
corresponds to the pressure in the vessel in which
the heat-sensing element is located.
To take into account pulsations originating from the
liquid injection, the pressure connection should be
located as far away from the liquid supply pipe as
possible.
It is recommended that the connection should be di-
rect on the top of the vessel or the upper side of the
suction line immediately after the vessel.
Under conditions where strong pulsations may occur,
it is recommended that a damping orifice should be
inserted in the delivery line to the element.
Accessories. See figs. 6 and 7.
Mains connection
a. Safety cut-out (fig. 2):
Phase
433
Fig. 4
Fig. 5
Fig. 6
Fig. 7
b. Liquid level control (fig. 3):
Phase
Cable diameter: 6 to 14 mm. The eart terminal 38
should be connected to earth.
Adjustment
Adjustment to the refrigerant required is effected by
setting the internal setting disc 5 at the mark indicating
the refrigerant in question on the scale 9.
Sicherheitsschalter
Niveauregler
Technische Daten
1. Allgemeines
Funktionsbereiche für RT 280A:
R 12
R 22, R 717
R 502
Funktionsbereich fur RT 281A:
R 22, R 502, R 717 –30°C bis +20°C
Niveaudifferenz: max. +20 mm bei max. Funktions-
temperatur und einer Niveauänderungsgeschwin-
digkeit von weniger als ca. 40 mm/min.
Umgebungstemperatur: –50°C bis 70°C (–50T70).
Schutzart: IP 66 nach IEC 529.
Schaltleistung: Siehe Kontaktdeckel oder Fig.5.
Die Kennzeichnung, z.B. 10(4) A, 400 V ~, gibt an
daß bei 400 V ~ maximal eine Belastung von 10 A
Compressor
ohmsch oder 4 A induktiv angeschlossen werden
darf. Der maximale Einschaltstrom beim Einschalten
Alarm
eines Motors (L.R.) darf bis zum siebenfachen der
induktiven Belastung betragen – jedoch max. 28 A.
RT genügt den Bedingungen nach VDE 0660.
614X3009
in ´
3 1
/ / in flare:
8 4
017-4205
Solenoid valve
open
Solenoid valve
closed
DEUTSCH
–50°C bis +10°C
–50°C bis 0°C
–65°C bis –5°C