S9360A, S9361A, S9380A, S9381A INTEGRATED BOILER CONTROLLERS
66-1203—05
14
Mounting Sensor and Thermowell
The remote upper temperature sensor is installed in an
immersion well (Fig. 9) that extends into the supply water
side of the boiler.
Immersion Well Fitting
The immersion well must snugly fit the sensing bulb for
good thermal response. Install as follows:
1.
Use tapping provided by tank manufacturer, if possi-
ble, or select an area where typical water tempera-
ture is best measured.
2.
If tank is filled, drain to below point where bulb will
be installed.
3.
Screw well into tank.
4.
Insert bulb into well, pushing wires until bulb bot-
toms in well.
5.
Attach mounting clamp end of well spud.
6.
With mounting clamp attached to well spud (make
sure jaws of clamp hook over ridge at end of spud,
as shown at points A in Fig. 9), adjust sensing lead-
wire to fit through mounting clamp groove, as shown
at point B in Fig. 9.
7.
Tighten draw nut until mounting clamp is firmly
attached to well spud and wires are held securely in
place.
CAUTION
Do not secure draw nut so tightly that
mounting clamp collapses tubing.
Fig. 9. Immersion well fitting for sensor.
Wiring
Disconnect power supply before installation to prevent
electrical shock or equipment damage. All wiring must
comply with local codes and ordinances regarding wire
size, type of insulation, enclosure, etc.
OPERATION AND CHECKOUT
Operation
The S9360A, S9361A, S9380A and S9381A continuously
monitor the temperature of the boiler water and enable or
disable the burner based on this temperature data. In
general, when a “Call for Heat” occurs, the ignition portion
of the control module proceeds through the steps
necessary to start the burner and heats the water in the
boiler until the setpoint temperature is achieved. At this
point the burner is de-activated, the ignition module
completes the heating cycle, returns to idle and waits for
the temperature to drop again. The circulator is turned on
throughout the “Call for Heat.”
See Fig. 10 for a graphical representation of a simple
control cycle. Note that the setpoint differential may vary
based on OS number.
High Limit Controller
All models include a 3-wire temperature sensor interface,
“Sensor 1,” which is utilized for High Limit functionality in
addition to the thermostatic control of the water heater
burner. If the temperature sensor ever indicates a
temperature above the maximum limit then the control
enters over temperature mode. In over temperature mode
no heating will occur.
Fig. 10. Basic control algorithm example.
Thermal Purge Operation
The intent of thermal purge is to insure usable residual
heat in the boiler is circulated until it is sufficiently
depleted from the system before the burner is allowed to
fire. To that end, on a call for heat, the burner is held off
while the circulator runs until the boiler temperature drops
to the thermal purge temperature limit or a time delay is
exceeded. Both of these parameters are adjustable.
When the boiler temperature falls below the thermal purge
temperature limit or the time delay expires, the burner is
allowed to fire.
In addition to the thermal purge temperature and thermal
purge time delay parameters, two other conditions release
the integrated boiler controller from thermal purge and
allow the burner to run in order to maintain comfort in the
space:
• The boiler temperature has dropped 10 °F from the
boiler water temperature measured at the beginning of
the beginning of the call for heat.
• Boiler temperature is cooling at a rate greater than
5 °F/minute while the circulator is running.
SENSOR WIRES
M23086A
HEAT-CONDUCTIVE COMPOUND
(OPTIONAL)
BOILER
IMMERSION
WELL
SENSOR
M27000
SETPOINT
GAS VALVE OFF
GAS VALVE ON
70
°F (21°C)
200
°F (93.3°C)
15
°F (8°C)
DIFFERENTIAL