The L7224A,C and L7248A,C,L 2012 Compliant Oil
Electronic Aquastat
temperature sensing in a UL limit-rated control with a
single sensing probe. The L7224A,C and L7248A,C,L
control the circulator, oil burner and boiler temperature.
The L7224/L7248 is “Outdoor Temperature Reset” ready
which is enabled when connected to the W8735S1000
Outdoor Reset Kit. Outdoor Reset with the L7224/L7248
is intended for all applications except for tankless coil
systems for domestic hot water. Compliance to 2012
DOE regulation ensures efficiency is maximized without
interfering with domestic hot water demand.
The L7224A,C and L7248A,C,L replace the L8124A,
L8124C, L7124A,C, L7148A and L8148A Controllers.
The L7224A,C and L7248A,C,L series controls provide
status and diagnostic information through an LED display
combined with LED lights as well as EnviraCOM™
communications enabled thermostats and diagnostic
tools to enhance the diagnostic process.
L7224/L7248 Aquastat Controllers are intended for use
in residential-type applications.
IMPORTANT
Use of Outdoor Temperature Reset on a tankless coil application requiring a Low Limit setting
will result in reduced system effectiveness and
efficiency.
®
Controllers provide electronic
Controllers
INSTALLATION INSTRUCTIONS
SPECIFICATIONS
Electrical Ratings:
Voltage: 120 Vac, 60 Hz.
Power: 7 VA maximum at 120 Vac plus external loads.
Thermostat current: 100 mA nominal at 24 Vac.
Burner Relay:
7.4 A at 120 Vac Full Load Amperage (FLA);
44.4 A inrush Locked Rotor Amperage (LRA);
Less Ignition Load: 360 VA.
Circulator Relay:
7.4 A at 120 Vac FLA; 44.4 A inrush LRA.
Zone Controller (ZC): 7.4 A at 120 Vac FLA;
44.4 A inrush LRA.
NOTE: All loads combined cannot exceed 2000 VA.
Environmental Ratings:
Temperature: -30 °F to +150 °F (-34 °C to +66 °C).
Humidity: 0 to 95% relative humidity, noncondensing.
Approvals:
Underwriters Laboratories Inc. Component Recognized.
Canadian Underwriters Laboratories Inc. Component
Recognized.
2012 DOE Compliance and Operation
Operation of this control may delay the burner operation while the residual heat is
circulated out of the boiler.
NOTE: This operation may be different than earlier electronic Aquastat®
revisions which did not implement thermal purge.
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a
hazardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
your application.
3. The installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
5. Set High Limit, Low Limit and Low Limit Differential
to the settings recommended by the boiler OEM.
6. Record the maximum High Limit setting from the
replaced controller in the text box provided on the
cover insert label.
7. Record the High Limit setting at time of installation
in the text box provided on the cover insert label.
Electrical Shock Hazard.
Can cause severe injury, death or property
damage.
Disconnect power supply before beginning
installation to prevent electrical shock or
equipment damage.
Mounting
The L7224A,C and L7248A,C,L models are available in a
well-mount, horizontal position, vertical position, or flush
mounted remote from the well versions. Dimensions for
the variety of mounting options are shown in Fig. 1. Note
that each identity will have only a single mounting option.
Fig. 1. L7224A,C; L7248A,C,L mounting dimensions in inches (mm).
Immersion well must fit sensing element and
sensor must rest against bottom of well.
New Installation
Order well assemblies separately; see Table 1 and form
no. 68-0040, Immersion Wells and Compression Fittings
for Temperature Controllers. Boilers usually have tappings
that allow the well to be mounted horizontally so boiler
water of average temperature can circulate freely over the
well.
1. Turn off all power and drain the boiler, if applicable.
2. If no tapping is provided, prepare properly sized and
threaded tapping near the top of the boiler.
3. Sparingly coat the well threads with pipe dope.
NOTE: Do not attempt to tighten by using the case
as a handle.
4. Install the well in the boiler tapping and tighten
securely.
5. Refill boiler and check for water leakage.
6. Loosen but do not remove the well clamp screw.
7. Fit the case into the well so the clamp on the case
slides over the flange on the well.
8. Securely tighten the clamp screw.
9. Insert the sensor element into the well until it bot-
toms. See Replacement Sensor Installation section
for details. (If necessary, slightly bend the wire
inside the case to hold the sensor against the bottom of the well.)
10. Turn power ON.
11. Set High Limit, Low Limit and Low Limit Differential
to the settings recommended by the boiler OEM.
(See OPERATION section.) (See INSTALLATION
steps 6 and 7.)
12. On L7248L models, adjust ELL option to match your
configuration (see OPERATION section, and Fig. 11
and 13).
IMPORTANT
Best thermal response is obtained with a well
that snugly fits the sensor. Insert the sensor until
it rests against the bottom of the well. Use a well
of correct length and bend the wiring, if necessary, to hold the bulb against the bottom of the
well.
If the well is not a snug fit on the sensor, use the
heat-conductive compound (furnished with
TRADELINE
plastic bag of compound lengthwise and twist it
gently. Then snip off end of bag and work the
open end of the bag all the way into the well.
Slowly pull out the bag while squeezing it firmly
to distribute compound evenly in the well. Bend
the wiring, if necessary, to hold the sensor
against the bottom of the well and to hold outer
end of the sensor in firm contact with the side of
the well. See Fig. 2. Wipe excess compound
from the outer end of the well.
®
models) as follows: Fold the
Fig. 2. Position of sensor in immersion well.
Flush-Mounted Aquastat
Replacement
Turn off all power and remove the old control. Refer to the
cover insert of the old control to identify and tag each
external lead as it is disconnected. If the old well is
unsuitable for the new installation, remove it and replace it
with a suitable new well. If the old well is suitable, use it.
Well-Mounted Aquastat
Replacement
Turn off all power and remove the old control. Refer to the
cover insert of the old control to identify and tag each
external lead as it is disconnected. If the old well is
unsuitable for the new installation, remove it and proceed
with instructions for new installation. If the old well is
suitable, use it.
1. Loosen, but do not remove, the well clamp screw on
the side of the control case.
2. Position immersion well clamp snugly over the
flange of the adapter and tighten the clamp screw.
3. Insert the sensor into the well as shown in Fig. 2 or
3. (See Replacement Sensor Installation section for
details.)
Fig. 3. Circuit board, showing sensor connection and
Electrical Shock Hazard.
Can cause serious injury or death.
Disconnect power supply before making wiring
connections to prevent electrical shock or
equipment damage.
All wiring must comply with local electrical codes and
ordinances. Do not exceed the specifications in the
Application section when wiring this control. Use wire
rated for 194 °F (90 °C) or higher.
Fig. 4. Replacement sensor installation.
Replacement Sensor Installation
Turn off all power and:
1. Carefully disconnect sensor from circuit board by
pulling gently on the connector.
2. Gently pull sensor from thermo well and through cir-
cuit board by pulling on leadwires.
3. Carefully align replacement sensor with hole in cir-
cuit board and guide through Aquastat case and
into well. (See Fig. 5).
4. Make sure sensor is fully seated to bottom of well
(See Fig. 4). Use a small pencil to measure depth of
sensor in well, if necessary.
5. Connect sensor to circuit board by pressing con-
nector on sensor unit into mating connector on circuit board (See Fig. 5).
6. For remote sensors (flush-mounted Aquastat Con-
trollers) be sure to use 121571AA Clamp (see
Accessories) to securely hold sensor in place.
IMPORTANT
The terminals on these Aquastat Controllers are
approved for use with copper wire only.
Follow the appropriate wiring diagrams shown on the
inside of the front cover of the L7224A,C; L7248A,C,L or
in Fig. 8–13.
Refer to Fig. 6 for Connections for the optional Outdoor
Reset Module and the Domestic Hot Water (DHW)
module. In subsequent wiring diagrams these modules
will be displayed with a dotted line signifying that they are
optional.
ZR
L1
L2
C2
B2
C1
B1
ZC
Fig. 6. Wiring the Outdoor Reset Module and the
50022037-002
OUTDOOR
RESET MODULE
T
3
T
2
1
LINE
1 2 3 OT OT
Domestic Hot Water Module.
C7089U1006
OUTDOOR
SENSOR
50022037-005
DOMESTIC HOT
WATER MODULE
1 2 3 TS TS
32003971-003
TEMPERATURE
SENSOR
M29651
Fig. 5. Circuit board, showing sensor connection and
Fuse
The 1 Amp fuse located near the transformer is intended
to protect the EnviraCOM circuit from incorrect wiring. The
Aquastat will continue to function should the fuse blow or
be removed though no EnviraCOM communication will be
possible on the bus and Err 6 will be displayed. See
Table 1 0 .
68-0281EFS—054
well holes for vertical mount models.
OPERATION
General
The L7224A,C and L7248A,C,L Oil Electronic Aquastat
Controllers are primary safety limit-rated devices
designed for use with oil fired boilers with line voltage
burners and circulators. Many boilers do not include
wiring or control compartments as part of the design, but
are provided with an integral, replaceable, immersion well
that is the mounting hardware for the Aquastat
Controllers. Wiring to the other controls is done through
flexible metal conduit.
For boilers that do include a remotely (flush) mounted
control, the wiring may be completed with conduit or
routed behind the boiler sheet metal.
A separate electromechanical high-limit is not required in
a system that uses this control to meet Underwriters
Laboratories Inc. requirements for oil-fired boiler
assemblies, UL 726.
On the L7224 models, the High Limit, Low Limit, Low Limit
Differential, and Anti Short-Cycle time can be adjusted to
the setting recommended by the boiler OEM. On the
L7248 models, the High Limit, and Anti Short-Cycle time
are also adjustable, see “Adjusting Settings”.
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.
Some models also have a Low Limit and Low Limit
Differential adjustment. 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 Zr setting can be set to DHW, Zoning, or for tankless
coil applications depending on the L7224/L7248.
If a W8735S1000 AquaReset™ Outdoor Reset Module is
installed, the reset curve can be set by entering the
minimum outdoor temperature, minimum (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
(-1.1 °C to 21.1 °C) and has a default setting of 40 °F. The
range of the minimum (water or boiler) temperature is
from 80 °F to 180 °F (26.7 °C to 82.2 °C) and has a
default setting of 130 °F. 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 L7224A,C and L7248A,C,L are designed for use with
24 Vac electronic and electromechanical thermostats or
EnviraCOM™ enabled thermostats, and have screw-type
terminals for easy field connection.
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. 5) simultaneously
for three seconds. Press the I button until the feature
requiring adjustment is displayed:
Table 3. Adjustable Features.
DisplayDefinition
HL_High Limit.
HdfHigh Limit Differential.
LL_Low Limit. (L7224A, C)
LdfLow Limit Differential (L7224A, C)
ELLExternal Low Limit (L7248L only)
duuZR input configured as external Domestic Hot
Water (DHW) request (ON/OFF) (L7224A,C/
L7248L)
ASCAnti 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)
tPL**Thermal Purging Limit Temperature (°F or °C),
“OFF” if disabled
tPt**Termal Purging Time Delay (minutes), shown
only if tPL is enabled
PCPump Cycling (ON / OFF)
F-CTemperature units (°F or °C)
* Settings available for adjustment on the 3-digit display
only if the W8735S1000 AquaReset Outdoor Reset
Module is installed.
**Settings available for adjustment only when the
W8735S1000 AquaReset Outdoor Reset Kit is NOT
installed.
Then press the UP and/or DOWN buttons to move the set
point to the desired value, to change between °F and °C,
or to enable (On) or disable (Off) the External Low Limit.
After 60 seconds without any button inputs, the control will
automatically return to the RUN mode.
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 High Limit
(HL) is displayed, followed by a three-digit number, i.e.,
220, followed by °F or °C. Pressing the I button again (on
L7224 models) will display the Low Limit (LL) followed by
a three-digit number and the corresponding degree
designator. See Display Readout, Table 4.
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 any key.
Display shows local setting; not the setting as modified by an
external enviracom control.
2
Settings are viewable only if the outdoor reset module and out-
door temperature sensor are installed and functioning properly.
3
Settings are viewable only if the domestic hot water module
and sensor are installed and functioning properly.
Operation
The L7224 and L7248 models can be in any of four
operational states: Normal, High Limit, Low Limit and
Error. The controller moves back and forth from
High Limit to Normal to Low Limit state as part of normal
operation. Only devices having High Limit settings are
restricted to the High Limit and Normal states. However,
the controller will enter the Error state when there is an
abnormal condition. The operating states are:
1. Normal: Boiler temperature went below the High
Limit setting (minus the Differential) and has not
exceeded the High Limit setting; or, the boiler
temperature went above the Low Limit setting and
68-0281EFS—056
2
3
2
2
2
2
(YES or NO)
2
2
2
has not gone below the Low Limit setting (minus the
Differential); or, ZR input is not powered with 120
Vac (only L7248L with ELL set On).
2. High Limit: Boiler temperature went above the High
Limit setting and has not dropped below the High
Limit setting (minus the Differential).
3. Low Limit: Boiler temperature went below the Low
Limit setting (minus the Low Limit Differential) and
has not gone above the Low Limit setting; or, ZR
input is powered with 120 Vac (only L7248L with
ELL set On).
4. Error: The controller has detected an error condition
(e.g., open sensor) and has shut down the burner
output. The ZC output is energized. The controller
continues to monitor the system and automatically
restarts if the error condition clears. Refer toTable 4.
The operating sequence for the L7224/L7248 is shown in
Table 6–9.
High Limit Controller
The High Limit opens and turns off the burner when the
water temperature reaches the setpoint. The High Limit
automatically resets after the water temperature drops
past the setpoint and through the Differential. The L7248
models have High Limit Differential presets of 15 °F
(8 °C). The L7224 models have High Limit Differential
presets of 10 °F (6 °C).
Low Limit and Circulator
Controller
On a temperature rise, with the adjustable Differential at
the default setting of 10 °F (6 °C), the burner circuit
breaks and the circulator circuit makes (assuming no call
for heat is present) at the Low Limit setpoint. On a
temperature drop of 10 °F (6 °C) below the Low Limit
setpoint, the burner circuit makes and the circulator circuit
breaks. See Fig. 7.
Fig. 7. Setpoints and differentials.
Anti Short-Cycle Feature
The Anti Short-Cycle feature allows for field selection of a
delay time between burner cycles. Should a call for heat
occur following the end of the previous heat cycle and
before the Anti Short-Cycle delay time is expired, the
circulator will be allowed to run, but the burner will be held
off until the time has elapsed. The range of the Anti ShortCycle time is from OFF to five minutes.
Water demand occurs. Domestic Hot Water
demands are serviced immediately, without
any delay.
NOTE: When the Aquastat is connected to the oil
primary and/or thermostat via the EnviraCOM
bus, the Anti Short-Cycle time does not apply
to recycle events such as loss of airflow or
flame. It applies only to loss of demand.
ZR-Domestic Hot Water (DHW)
Request
The ZR terminal can be selected to service an indirect
water heater heat request. This parameter is set via the 3
digit display (see Adjusting Settings section of this
document). A heat request via the ZR terminal will have
priority over all other features such as the Anti ShortCycle feature or those enabled by the Outdoor Reset
Module (See form #69-2335 for more information).
Frost Protection
The Frost Protection function protects the boiler and
potentially the boiler plumbing from possible damage
which may occur should the water in the system begin to
freeze. The Frost Protection feature is enabled only in the
L7248 (cold start models). The feature default setting is
enabled (ON), but can be disabled using the 3-digit
display. See “Adjusting Settings” on page 5.
When the Boiler temperature drops to the Frost Protection
Limit temperature (fixed 40 °F), the burner is forced on.
The Circulator and ZC outputs remain in the same state
as before the Frost Protection function was enabled.
They can be either ON or OFF during the Frost Protection
cycle.
Table 5. Thermal Purge Settings.
Parameter nameMinimum valueMaximum ValueDefault
Boiler temperature dropNot adjustableNot adjustable10 °F
Thermal purge temperature limit120 °F (or OFF)160 °F140 °F (L7248)
Thermal purge temperature rate of dropNot adjustableNot adjustable5 °F/minute
Thermal purge time delay1 minute10 minutes2 minutes
When the Boiler temperature reaches the Frost Protection
Limit temperature plus a fixed 10 °F differential, the burner
is turned off unless requested to stay on due to a different
demand.
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 or a time delay is
exceeded. Both of these parameters are adjustable.
When the boiler temperature reaches the thermal purge
temperature, the burner is allowed to fire. Thermal purge
is only applied to cold start Aquastat models (L7248) and
will not interfere with domestic hot water call for heat or
boilers equipped with Honeywell outdoor reset
accessories. For warm start models where a Low Limit
must be set, thermal purge is not applied.
In addition to the thermal purge temperature and thermal
purge time delay parameters, two other conditions release
the Aquastat from thermal purge in order to maintain
comfort in the space:
• The boiler temperature has dropped 10 °F from the
beginning of the thermal purge.
• Boiler temperature is cooling at a rate greater than
5 °F/minute while the circulator is running.
The thermal purge feature applies to single zone as well
as multi-zone applications.
Thermal Purge Settings
Some thermal purge parameters are configurable using
the 3 digit display. See “Adjusting Settings” on page 5.
Thermal purge may be disabled by setting the thermal
purge temperature limit to "OFF".
Thermal Purge and Domestic Hot
Water
The thermal purge feature is automatically disabled
whenever there is a call for domestic hot water from the Zr
terminal to ensure hot water is available in a timely
manner. See “ZR-Domestic Hot Water (DHW) Request”
on page 7.
Pump Cycling
The Pump Cycling feature exercises the system pump for
15 seconds after a non-adjustable five day period of no
boiler activity. The Pump Cycling feature default setting is
enabled (ON) but can be disabled (OFF) using the 3-digit
display. See “Adjusting Settings” on page 5.
CHECKOUT
Put the system into operation and observe at least one
complete cycle to make sure that the controller operates
properly. See TROUBLESHOOTING section to use LED
to assist in determining system operation.
TROUBLESHOOTING
When attempting to diagnose system performance,
reference to the LED display can help to identify specific
areas not working properly. The LED display will scroll
Err, followed by a digit (1-8). Refer to Table 10 and 11 for
a description of each error and suggested actions.
Thermostat calls for heat.Circulator starts when water temperature is above Low Limit setting (if
Boiler temperature exceeds the High Limit.Burner is turned off. Burner restarts when the water temperature
applicable) or above the Thermal Purge Temperature Limit (tPL) if
Thermal Purge is enabled. Boiler temperature is checked. Burner
starts when water temperature is below High Limit setting minus the
differential or at or below the Thermal Purge Temperature Limit (tPL)
for cold start boilers if the Thermal Purge Temperature Limit is
enabled. If tPL is enabled, the burner may also start if the boiler
temperature is cooling at 10 ºF or greater per minute or the Thermal
Purge Time Delay (tPt) has expired.
If Anti Short-Cycle Time is enabled, the burner does not start until the
set Anti Short-Cycle Time between cycles expires after the previous
call for heat was satisfied.
drops below the High Limit setting minus the Differential. If Thermal
Purge is enabled, the burner is turned on when either the Thermal
Purge Temperature Limit is reached, the Thermal Purge Time Delay
has expired or the boiler temperature cooling rate exceeds 10 ºF/
minute.
Thermostat is satisfied.Circulator and burner turn off.
Boiler temperature drops below the Low Limit
setting minus the differential (if applicable).
Error condition
1-5.
Burner is turned on, Circulator is turned off. Burner stops when the
water temperature exceeds the Low Limit setting. Power to Zc is
removed.
If an error condition is detected, all outputs except ZC are shut down.
Burner is off. Control continues to function and restarts when error is
corrected.
During the error check sequence, the system checks for drift in the
sensor and corrosion in the connections.
Error condition 6.EnviraCOM communication is not available.
Error condition 7.The control has reset the High Limit, Low Limit and Differential setting to
Error condition 8.If the error condition is detected, all outputs except ZC are shut down.
a default setting and will continue to run at those settings.
Performance of the system will be degraded.
Burner is off. Control continues to function and restarts when all three
user keys have been pressed longer than 60 seconds.
Error condition 9*.System continues to run with no outdoor reset functionality
Error condition 10*.System continues to run with outdoor reset parameters enabled as
programmed. Error cleared automatically.
Error condition 11*.System continues to run with boiler temp set to High Limit.
* Error condition only available when the Outdoor Reset Module is installed.
Table 7. L7224/L7248 Controller Operating Sequence with multiple zones connected through the ZR terminal.
ActionSystem Response
Zone Request (ZR) terminal is connected to
L1 (Zone calls for heat).
Boiler temperature exceeds the High Limit.Burner is turned off. Burner restarts when the water temperature
Zone Request input is de-energized (Zones
are satisfied).
Boiler temperature drops below the Low Limit
setting minus the differential (if applicable).
Boiler temperature is checked. Burner starts when water temperature
is below High Limit setting or at or below the Thermal Purge
Temperature Limit (tPL) for cold start boilers if the Thermal Purge
Temperature Limit is enabled. If tPL is enabled, the burner may also
start if the boiler temperature is cooling at 10 ºF or greater per minute
or the Thermal Purge Time Delay (tPt) has expired. Anti Short-Cycle
Time is applied, see Table 6.
drops below the High Limit setting minus the Differential. If Thermal
Purge is enabled, the burner is turned on when either the Thermal
Purge Temperature Limit is reached, the Thermal Purge Time Delay
has expired or the boiler temperature cooling rate exceeds 10 ºF/
minute.
Burner turns off.
Burner turns on and Zone Control is de-energized. Burner turns off
and Zone Control is re-energized when the water temperature
Table 8. Controller Operating Sequence with External Low Limit device connected trough the ZR terminal.
ActionSystem Response
Zone Request (ZR) terminal is connected to
L1 (External Low Limit call for heat).
Boiler temperature exceeds the High Limit.Burner is turned off. Burner restarts when the water temperature
Zone Request input is de-energized (External
Low Limit is satisfied).
Boiler temperature is checked. Burner starts when water temperature
is below High Limit setting. Circulator turns off.
drops below the High Limit setting minus the Differential.
Burner is turned off.
Table 9. L7224 Controller Operating Sequence with Domestic Hot Water connected trough the ZR terminal.
ActionSystem Response
Zone Request (ZR) terminal is connected to
L1 (Domestic Hot Water calls for heat).
Boiler temperature exceeds the High Limit.Burner is turned off. Burner restarts when the water temperature
Zone Request input is de-energized
(Domestic Hot Water is satisfied).
Boiler temperature is checked. Burner starts when water temperature
is below High Limit setting.
drops below the High Limit setting minus the Differential.
Burner is turned off.
Table 10. LED Error Codes.
Aquastat
Error CodeCause/Action
EnviraCOM
Alarm
Err1Aquastat sensor fault; check water sensor.18
Err2ECOM fault; check EnviraCOM™ wiring.18
Err3Excessive electrical noise or frequency out of range. Hardware fault; replace controller.18, 58
Err4B1 fault; check B1 wiring/voltage.64
Err5Low Line; check L1-L2, 110 Vac.59
a
Err6
Warning: Fuse; check ECOM wires, replace fuse.92
Err7Warning: EEPROM, HL, LL, Hdf, Ldf; reset to default values.N/A
b
Err 8
Err9
Err 10
Err 11
a
Warnings are generated to enunciate the system is not operating optimally, but the Aquastat is still operating and
maintaining boiler temperature. In the instance where an Outdoor Reset Module is used, the warnings may indicate a
reset curve setting error one or more features is not running optimally, and the Aquastat is reverting to default settings
or has stopped running the Outdoor Reset algorithms. The warnings are cleared when the issue(s) is resolved.
b
To clear Err 8 condition, depress and hold all three user keys simultaneously for 60 seconds. Err 8 condition clears
and display returns to normal. Err 8 condition is designed to catch welded relays on the Aquastat and will normally
only occur near end of life for the control. If Err 8 condition has occurred early in the controls life, be sure to check for
voltage feedback to B1 when B1 should be off and check current draw on b terminal to be sure oil burner is not drawing excessive current. Err 8 condition will keep repeating if B1 fault is not cleared.
Repeated B1 fault (voltage present at B1 when output is turned off); check B1 wiring/voltage. 25
a
Warning: Outdoor Reset System failure; communication to Outdoor Reset Module lost,
Outdoor Reset Module failure, multiple outdoor temperature sensors detected on the bus, or
outdoor temperature sensor failure. Check EnviraCOM wiring (1, 2, 3), check sensor wiring.
a
Warning: Boost Failure; Boost Mode active at least once per cycle for the last 60 consecutive
cycles. Check Outdoor Reset curve settings.
a
DHW Module/Sensor failure; communication to DHW Module lost, DHW Module failure, or
temperature sensor failure. Check EnviraCOM wiring (1, 2, 3), check sensor wiring.
50, 53, 149
150
146, 147,
148
Table 11. Troubleshooting Guide
System
Condition
Boiler is cold,
house is cold.
Diagnostic
ConditionCheckAction
Display is OFF. 120 Vac System power.Turn system power on.
Display is ON.24 Vac T-TNo 24 V; replace control.
24 V present; disconnect
thermostat, short T-T.
120 Vac at B1-B2• If no, replace control.
Refer to Err on display.—
68-0281EFS—0510
Boiler starts, check wiring and thermostat.
• If yes, check burner and wiring.
System
M27115
POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
CONTROL CASE MUST BE CONNECTED
TO EARTH GROUND. USE GROUNDING
SCREW PROVIDED.