Operation; Adjustments - Honeywell AQUASTAT L6188A-C User Manual

PROTECTORELAY
CONTROL
HIGH LIMIT
2
BLACK
BURNER MOTOR
ORANGE
IGNITION
WHITE
T
T
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
1
PROTECTION AS REQUIRED.
L4188 OR L4189 USED AS HIGH LIMIT.
2
L6188 OR L6189 USED AS LOW LIMIT/CIRCULATOR CONTROLLER.
3
Fig. 9. High Limit and Low Limit/Circulator Application in
an Oil-Fired Hydronic System with domestic hot water.
24V
THERMOSTAT
SWITCHING RELAY
RA832A
T T 2
1
X X 4
L4188.9
CIRCULATOR
L4188.9
LOW LIMIT
LINE VOLTAGE
LOW VOLTAGE
PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS
1
REQUIRED.
Fig. 10. High Limit and Separate Low Limit and Circulator
Application in an Oil-Fired Hydronic System with
Domestic Hot Water.
L4188A,B; L4189A,B; L6188A-C; L6189A-C AQUASTAT® CONTROLLERS
24V THERMOSTAT
RELAY CENTER
R G L1
(HOT)
L2
3
LOW LIMIT
C 1
CIRCULATOR
MOTOR
CIRCULATOR
2
M25422
1
L1 L2
(HOT)
L4188.9
HIGH LIMIT
BLACK
WHITE
IGNITION
ORANGE
T
CIRCULATOR BURNER
T
PROTECTORELAY
CONTROL
M25423

OPERATION

As the liquid filing the sensing bulb and capillary expands and
contracts, it moves a diaphragm. Movement of the diaphragm
is transferred by a lever to the snap-acting switch in the
controller.
High or Low Limit Action (L4188, L4189)
The normally closed C-1 contacts open on temperature rise to
the set point, shutting off power to the controlled circuit. On
auto recycle models, the switch closes C-1 after the
temperature falls past the set point and through the differential
(See Fig. 11).
Low Limit/Circulator Action (L6188, L6189)
The low limit is connected to the normally closed C-1 contacts,
and the circulator to the normally open C-2 contacts. As long
as the temperature at the sensing bulb is above set point, the
circulator runs. If sensing bulb temperature falls past the set
point and through the differential, the switch breaks C-2 to turn
off the circulator, and makes C-1 to turn on the burner. When
the temperature rises to the set point, C-2 makes to turn on the
circulator, and C-1 breaks to turn off the burner.
On manual reset models, the reset button must be pushed
before contacts C-1 will close (See Fig. 11).
TEMPERATURE
SETTING
SCALE
220 F
SET POINT
DIFFERENTIAL
100 F
Fig. 11. Aquastat Controller Switch Action on Temperature

ADJUSTMENTS

To Set Temperature
KNOB MODELS
Line up the desired temperature setting with the temperature
setting indicator behind the knob.
SCREWDRIVER SLOT MODELS
Line up the pointer on the shaft with the desired temperature
setting printed on the case.
7
L4188.9 L6188.9
HIGH OR LOW LOW LIMIT/
LIMIT CIRCULATOR
2
SET POINT
MANUAL
C 1
C 1
RESET
BREAKS
MAKES C-1
C-1 BREAKS
C-2 MAKES
2
AUTO
RECYCLE
2
SET POINT
C 1
LESS
C 1
DIFFER-
MAKES
C-1 MAKES
ENTIAL
C-2 BREAKS
Change.
1
C
M25424
68-0061—1