162 167 heaters_gb

1. 162

2. 163
Heaters
Heaters
Heaters
Benefits, technical details 164
Continuous thermal output 10 – 300 W 166
Particularly with fluctuating ambient temperatures, such as those
that occur with outdoor enclosure siting or in unheated rooms,
enclosure heaters must be used to prevent condensation.
All Rittal enclosure heaters operate on the basis of state-of-the-art
PTC technology.
Practical example of heaters
Extreme temperature fluctuations provide
the ideal conditions for the formation of
condensation. Particularly when enclosures
are sited outdoors, it is essential for the
built-in electronics to function reliably.
In order to maintain operational reliability,
enclosure heaters are used.
Where there is a risk of frost, the heater
keeps the temperature level inside the
enclosure at the operating temperature of
the built-in electronic components. If there
is a risk of condensation, the enclosure
internal temperature is raised to above the
dew point – hot air is capable of absorbing
more humidity – thus helping to counteract
condensation on electronic components.
In particular, heaters with an integral or
additional fan offer even greater efficiency.
Enclosure heaters may be easily snap-
mounted onto the 35 mm DIN EN 50 022
support rail, for example, or screw-fas-
tened onto the mounting plate.
The heaters are easily controlled using a
thermostat and/or hygrostat.
1
2
Heater
Electronic
components
1
2

3. 164
Heaters
Benefits, technical details
Rittal system climate control
Especially with outdoor siting, but also indoors, condensation
poses a particular risk for control electronics. 7 different output
categories ensure that the correct thermal output is always
available. In this way, the total thermal output required can be
distributed precisely within an enclosure, thereby effectively
avoiding the overheating of individual components.
Output and application diversity
The output range of the three
different Rittal enclosure
heater systems, from 10 to
1,000 watts, ensures a high
level of heating effectiveness in
a confined space.
The designs without fan and
with fan (thermal output from
50 to 160 m3/h) provide a solu-
tion for every specific applica-
tion.
Particularly in outdoor use,
condensation poses a high
risk. This may be counteracted
by a regulated heater coordi-
nated to the enclosure size and
temperature difference.
Simple assembly and reliable control
Fast assembly
This is achieved with a screw
or snap fastening on the
mounting plate or 35 mm
DIN EN 50 022 support rails.
No condensation, and always
the right temperature
The heater is activated as
required via the hygrostat or
enclosure internal thermostat.

4. 165Rittal system climate control
Heaters
30°C
150°C
160°C
170°C
130°C
140°C
120°C
80°C
90°C
110°C
100°C
60°C
70°C
50°C
40°C
1
2
Benefits:
● Useful cooling output
from 10 to 1000 watts
● Self-regulating PTC tech-
nology
● Quick-assembly system
Important
● For the correct tempera-
ture and to avoid conden-
sation, use a thermostat
or hygrostat –
cf. page 175
● Heaters should always be
installed in an upright
position. Leave a dis-
tance of 50 mm at the top
and bottom to allow con-
vection
● The thermal output is
increased with fans
● Heat is distributed evenly
in large enclosures by
using several low-output
heaters
For general comments,
see page 186
Calculation formulae,
see page 187
or refer to the Internet at
www.rittal.de
The benefits of modern thermistor technology (PTC)
The prerequisite for optimum
conversion of electrical energy
into thermal energy is perfect
interaction between the thermal
output, surface temperature
and ambient temperature.
Conventional resistor heaters
The surface temperature is limi-
ted via an additional safety
thermostat. As a result, the
heater is forever cutting in and
out, which means that the con-
tinuous thermal output actually
produced is low.
Rittal heaters with
PTC technology
Unlike conventional resistance
heaters, in thermistors (PTCs),
power consumption automati-
cally decreases as the intrinsic
temperature rises. The advan-
tages of this dynamic output
behaviour are as follows:
● Surface temperature is limi-
ted without the need for
additional temperature pro-
tection devices
● Self-regulation achieves
direct adaptation to the
ambient temperature. In
other words, as the enclo-
sure internal temperature
falls, the thermal output
increases (cf. performance
diagrams).
● A constant thermal output
throughout a broad voltage
range (e.g. 110 to 240 V
AC/DC).
● Special voltages are pos-
sible in the low voltage range
(e.g. 12 V, 24 V)
● Long service life
● Compact, vibration-free
mechanical structure
● In the event of a malfunc-
tion, there is no risk of fire
from incandescent elements
Temperature variation through the
aluminium section (Tu = 20°C) using
the example of the heater SK 3102.000
= Temperature variation without fan
= Temperature variation with fan
1
2

5. 166 Rittal system climate control
75
4535
80
125
4535
130
80
118
140
25
5.2
8.25
162
100
110
45 64
185
6445
168
□
120
Technical specifications:
● Limitation of surface temperature via a
PTC thermal element.
● If an axial fan (SK 3108.000) is attached
to the heater SK 3107.000, its effective-
ness may be enhanced.
● All heaters are quickly and easily
mounted using the supplied screw and
snap fastenings.
● Snap fastening for 35 mm support rail
DIN EN 50 022.
● Maximum effectiveness is achieved by
installing the enclosure heaters vertically,
with the cable routing pointing down-
wards.
● In order to create the necessary convec-
tion, 50 mm spacing from the top and
bottom is required. The distance from
neighbouring components must be at
least 50 mm.
● The unit housings are made from robust,
black anodised aluminium.
Supply includes:
Unit ready to install with permanently
attached connection cable (0.3 m).
SK 3102.000 with fitted fan including
terminal strip.
Note:
● Thermostat SK 3110.000 (see accesso-
ries) is recommended for precise tem-
perature control in the enclosure.
● In order to prevent condensation on
assemblies, hygrostat SK 3118.000
(see accessories) is recommended to
regulate heating.
● In larger enclosures, even heat distribu-
tion is best achieved by installing sev-
eral low-output heaters.
● Internal installation is generally advis-
able, even when using heat exchangers
and cooling units, in order to prevent
condensation.
Model No. SK 3105.000 3106.000 3115.000 3116.000 3107.000
3107.000 +
3108.000
3102.000
(incl. fan)
Rated operating voltage V, Hz 110 – 240 V AC/DC
110 – 240 V
AC/DC
230 V, 50/60
Continuous thermal output at Tu = 20°C 10 W 20 W 30 W 50 W 130 W 200 W1) 300 W1)
Pre-fuse T 2 A 4 A
Special voltages available on request. We reserve the right to make technical modifications. 1) Output with fan.
Accessories Packs of Page
Thermostat 1 3110.000 175
Hygrostat 1 3118.000 175
Temperature indicator 1 3114.100 174
SK 3105.000 SK 3106.000 SK 3107.000
SK 3115.000 SK 3116.000 SK 3102.000
including fan
Axial fan
for heater SK 3107.000
Ball bearing
Temperature range: –40°C/+85°C
Rated operating voltage: 230 V, 50/60 Hz
Power consumption: 18 W
Noise level: 33 dB (A)
Speed: 2800/3300 rpm
Air throughput: 50 m3/h
38
3 3
79.5
79.5
6
71.5
71.5
4.3
310
Model No. SK 3108.000
Earthing lug
for M4 or
8 – 32 UNC

6. Enclosure heaters
Continuous thermal output 10 – 300 W
167Rittal system climate control
Enclosureheaters
With this heater, an axial fan
supports heat distribution
inside the enclosure.
Approvals,
see page 23.
Performance diagrams
Model No. SK
3102.000 / 3107.000
= SK 3102.000 (with fan SK 3108.000)
= SK 3107.000 (with fan)
= SK 3102.000 (without fan)
= SK 3107.000 (without fan)
°C
W
200
– 20– 30 – 10 0
150
100
250
300
350
+ 30+ 10 + 20
1
2
3
4
1
2
3
4
3105.000 / 3106.000 /
3115.000 / 3116.000
°C
W
45
30
35
40
50
55
60
65
– 10– 20
5
10
15
20
0 + 10 + 20 + 30
25
SK 3115.000
SK 3116.000
SK 3106.000
SK 3105.000
Functional diagram