L7224U OIL ELECTRONIC AQUASTAT
®
CONTROLLER
5
69-1720—03
The overall range of the High Limit is from 130° F to
240° F (54° C to 116° C). Select devices may have
different ranges. Some models have limited ranges on the
High Limit setpoint; this limited range is listed on the
device label.
The range of the Low Limit is from 110° F to 220° F
(43° C to 104° C). Select devices may have different
ranges. The range of the Anti-Short Cycle time is from 10
seconds to five minutes.
If a 50022037-002 “Outdoor Reset Module” is installed,
the reset curve can be set by entering the minimum
outdoor temperature, minimum (water or boiler)
temperature, and maximum outdoor temperature on the
3-digit display. The range of the minimum outdoor
temperature is from -40°F to 40°F (-40°C to 4.4°C) and
has a default setting of 0°F (-18°C). The range of the
maximum outdoor temperature is from 30°F to 70°F (-1°C
to 21°C) and has a default setting of 40°F (4.4°C). The
range of the minimum (water or boiler) temperature is
from 80°F to 180°F (27°C to 82°C) and has a default
setting of 130°F (54°C). See the “Outdoor Reset Module”
Installation Instructions (form number 69-2335) for more
information on setting the boiler reset curve and all related
parameters.
The L7224U is designed for use with 24 Vac electronic
and electromechanical thermostats and EnviraCOM™
enabled thermostats, and have screw-type terminals for
easy field connection.
To replace a L8148A,C L7148A or L7248A,C controller,
the Low Limit function must be disabled; see Adjusting
Settings for directions.
Adjusting Settings
To discourage unauthorized changing of Aquastat
settings, a procedure to enter the
ADJUSTMENT
mode is
required. To enter the
ADJUSTMENT
mode, press the
UP
,
DOWN
, and
I
buttons (refer to Fig. 9) simultaneously
for three seconds. Press the
I
button until the feature
requiring adjustment is displayed:
• HL_ — High Limit.
• Hdf — High Limit Differential.
• LL_ — Low Limit.
• Ldf — Low Limit Differential.
• duu — ZR input configured as external Domestic Hot
Water (DHW) request (ON/OFF)
• ASC — Anti Short-Cycle Timeout (seconds); “OFF” is
disabled.
• otL — Outdoor Temperature Low (minimum)
parameter for the outdoor reset curve (F or C)*
• otH — Outdoor Temperature High (maximum)
parameter for outdoor reset curve (F or C)*
• btL — Boiler Temperature Low (minimum) parameter
for outdoor reset curve*
• bP — Boost Period (minutes). “OFF” is displayed if
Boost is inactive*
• bS — Boost step (F or C) shown only if Boost is active
(bP=ON)*
• UUS — Warm Weather Shutdown Temperature (F or
C)*
• F-C — Temperature units (F or C)
* Settings available for adjustment on the 3-digit display
only if the AquaReset Outdoor Reset Module is installed.
Then press the
UP
and/or
DOWN
buttons to move the set
point to the desired value. After 60 seconds without any
button inputs, the controller will automatically return to the
RUN
mode.
To use the L7224U in a cold start boiler application,
disable the Low Limit function by pressing the
UP
arrow
button,
DOWN
arrow button and
I
button simultaneously
for three seconds. Then push the
I
button until
LL_
is
displayed. Then press the down arrow button until
OFF
is
displayed.
Display
In the RUN mode, the Aquastat will flash “bt” (boiler temp)
followed by the temperature (i.e., 220), followed by °F or
°C.
To read boiler settings, press the
I
key to read the
parameter of interest. For example, press
I
and
HL
(High
Limit) is displayed, followed by a three-digit number, i.e.,
220, followed by °F or °C. Pressing the
I
button again will
display the
LL
(Low Limit) followed by a three-digit
number and the corresponding degree designator. See
Fig. 7 for explanation of display readout.
After approximately 60 seconds without any key presses,
the display will enter a dim display mode. To return to the
bright display mode, simply press and release any key.
