3
SETTING THE CONTROL
WIRING
CONTROLS WITH ADJUSTABLE DIFFERENTIAL
The left-hand indicator points to the temperature at which the
contacts open on high limit and low limit applications. On
circulator applications, the left-hand indicator points to the
temperature at which the circulator will start.
On combination low limit and circulator applications, the
left-hand indicator points to the temperature at which the low
limit stops the burner and permits the circulator to run.
1. Insert screwdriver in the centre slot and turn the dial until the
right hand indicator (B) points to the lowest temperature of
the cycle.
2. Turn the differential adjusting screw (C) until the left hand
indicator (D) points to the highest temperature of the cycle.
CONTROLS WITH FIXED DIFFERENTIAL
The fixed indicator points to the temperature at which the contacts
open on high limit and low limit applications. On circulator
applications, the fixed indicator points to the temperature at
which the circulator will start.
On combination low limit and circulator applications, the
fixed indicator points to the temperature at which the low limit
stops the burner and permits the circulator to run.
Insert screwdriver in center slot and turn the dial until the fixed
indicator (B) points to the highest desired temperature of the cycle.
The R-B contacts of the low-limit circulator control maintain
domestic hot water at the desired temperature year-round.
When the thermostat calls for heat, the burner starts. The cir-
culator also starts if the R-W contacts of the low-limit circulator
control are closed.
If excessive boiler temperature causes the high limit to open,
the circulator continues to run but the burner shuts down until
the high limit recloses.
If low boiler temperature causes the R-W contacts of the low-limit
circulator control to open, the burner stays on but the circulator
stops until the R-W contacts reclose.
When the thermostat is satisfied, the circulator stops. The burner
also shuts down if the R-B contacts of the low-limit circulator
control are open.
“B” FIXED INDICATOR
(CUT-IN POINT)
“C” DIFFERENTIAL
ADJUSTING SCREW
“D” MOVABLE INDICATOR
(CUT-OUT POINT)
“A” ADJUSTING
SLOT
“B” FIXED
INDICATOR
“A” ADJUSTING
SLOT
To Next Page