MU1R-9023 0208R12-NE
2
Table 1. L4188/L6188 and L4191/L6191 models
INSTALLATION
IMPORTANT
Take care that installer is a trained experienced
service man.
The L4188/L6188 and L4191/L6191 aquastats do
not require lubrication.
Mounting
Follow the mounting instructions supplied by the boiler or
burner manufacturer when available.
Where no special instruction is given, follow the procedure as
outlined below:
Drain the water from the heating system.
Screw the immersion well into a
1
/
4
” or
1
/
2
” pipe tapping
and tighten (use a good wrench, do not use the device
for this purpose).
Refill the heating system with water and test the
immersion well for water tightness.
Insert the temperature sensor(s) into the well untill it
bottoms and hold in position while securing with the
screw provided.
Wiring
CAUTION
Disconnect power supply to prevent electrical shock
and/or equipment damage.
Wiring must be in accordance with local regulations.
The appliance manufacturer’s instructions should
always be followed when provided.
Remove the front cover and conduit box(es) and insert
the cable through the conduit box(es).
Wire the thermostat into the circuit.
Mount the conduit box(es) and screw on the front
cover.
ADJUSTMENTS
WARNING
Adjustments must be made by qualified persons only.
If the appliance manufacturer supplies checkout and/
or service and maintenance instructions carefully
follow them. If these instructions are not provided
then use the procedure outlined below.
The L4188/L6188 and L4191/L6191 aquastats have
been factory calibrated, field calibration should not be
attempted.
Type
Temperature range (
°
C)
Switching differential (
°
C)
Switch type
Setting means
L4188A
25 ... 95
40 ... 110
4
SPST
Knob setting
L4188B
Internal setting
L6188A
25 ... 95
40 ... 110
70 ... 140
4 ... 10 (adjustable)
SPDT
Knob setting
L6188B
4
4 ... 10 (adjustable)
Internal setting
L6188C
25 ... 95
70 ... 140
Manual reset
SPDT
Internal setting
L4191A
Controller
Limiter
25 ... 95
4
SPST
Knob setting
Internal setting
L4191B
Controller
Limiter
25 ... 95
70 ... 140
4
SPST
Knob setting
Manual reset
SPDT
Internal setting
L6191A
Controller
Limiter
25 ... 95
50 ... 95
40 ... 110
4
4 ... 10 (adjustable)
SPDT
Knob setting
4
SPDT
Internal setting
L6191B
Controller
Limiter
25 ... 95
40 ... 110
70 ... 140
4
4 ... 10 (adjustable)
SPDT
Knob setting
50 ... 95
40 ... 110
70 ... 140
Manual reset
Internal setting
1
2
3
4
1
2
3
