Technical data

9
KK
Bimetal Room temperature controllers
General Technical Explanations
1. Mounting
These room temperature controllers,
which can be mounted independ-
ently, are for regulating normal
ambient temperature in dry and
enclosed rooms only.
The controllers have radio inter -
ference suppression in accordance
with VDE 0875 or EN 55014.
Admissible relative room humidity:
max. 95% (without condensation).
When the temperature setting
knob is turned, the switching point
is lower than when the tempera -
ture controller operates auto -
matically. The precise switching
point is only attained after approx.
1 to 2 hours.
2. Electrical connections
Always connect mains Neutral to
the appropriate terminal provided.
Otherwise, there will be drastic
temperature fluctuations and long
cycling times. The correct cycling
rate is 5 to 6 times per hour.
Make sure that the polarity of ter-
minals L and Load is correct. Mixing
up these two terminals will result in
constant thermal feed back as well
as a decreased switching point, i.e.
the controller will not provide
enough heat.
3. Break contact
The controller contact opens when
the temperature rises and closes
again when the temperature falls
(for “heating”).
4. Make contact
The controller contact closes when
the temperature rises and opens
when the temperature falls (for
„cooling“).
5. Change-over
This is a change-over switch with
make and break contacts. See
Sections 3 and 4 concerning its
operation.
6. RF (ACC) / Thermal feedback
It takes a certain amount of time
before heat from the energy source
is conducted via room air currents
to the temperature controller. Gen-
erally, by the time the bimetal strip
in the room temperature ontroller
heats up, more heat has been pro-
duced than the setting actually re-
quires. The superfluous rise in tem-
perature can only be prevented if
the room temperature contoller
shuts off before the surplus heat is
produced. This is taken care of by a
small heat resistor (thermal feed-
back resister) located right next to
the bimetal strip. As soon as the
room temperature controller re-
quires heat, voltage is applied to
the resistor, which then „deceives“
the bimetal strip by simulating a
room temperature that in actuality
has not yet been attained.
7. TA / Temperature set-back
As with thermal feedback, temper-
ature set-back is likewise brought
about by a resistor. The heat resis-
tor is activated by either a manual
switch or a timer.
This „deceives“ the bimetal strip by
simulating a temperature that is
approx. 5 K higher than what is ac-
tually present in the room. Thus,
the room temperature when the
button is set, for example 20°C,
may drop by 5 K to max. 15°C. If the
temperature drops any lower, the
heat is turned back on, shutting off
again when 15°C is exceeded.
The number of degrees the temper-
ature drops from day to night de-
pends on building insulation and
the set-back time period (overnight,
over the weekend or for several
days, e.g. holidays).