2
A
B
C
D
E
F
H
I
G
Product program
This user manual covers following thermo-
stats with built-in GFCI
LXstat-420 Incl.
fl oor sensor 3m
LXstat-421
With built-in room
sensor
Introduction
The thermostat is an electronic on/off ther-
mostat for control of temperature by means
of an NTC sensor either placed externally
or internally in the thermostat. The thermo-
stat has integrated a Ground Fault Circuit
Interrupter (GFCI, Class A). The thermostat
and the GFCI is a dual model suitable for
120/240 V 50/60 Hz supply.
The thermostat type LXstat-420 has an
external temperature sensor that is normally
placed in the fl oor construction. In this con-
fi guration the thermostat
controls the temperature of the fl oor and
not the temperature within the room. The
thermostat type LXstat-421 has a built-in
temperature sensor. In this confi guration the
thermostat controls the temperature of the
room.
The thermostat has two adjustable set
points, one for the day operation and one
for the night setback temperature. Switching
between the two set points is easily done
with one push at the OK ( ) button.
The temperature can be displayed in eigher
°C or in °F. Switching can be done on the pin
button marked with ( )
The thermostat has a pin button marked R,
allowing you to reset the thermostat to fac-
tory settings. These are listed at the end of
this manual with space for you to record your
settings.
1. Getting started
Buttons
A: Reset of GFCI
B: Red light indicating ground fault
C: Test of GFCI
D: Pin button ºC / ºF
E: Display
F: Reset to factory setting
G: Adjustment down
H: OK - accept
I: Adjustment up
