Honeywell Aquastat L7224U User manual

INSTALLATION INSTRUCTIONS
69-1720EFS-07
L7224U Oil and Electric Boiler
Electronic Aquastat®Controller
APPLICATION
The EnviraCOM™ enabled L7224U Electronic Aquastat®
Controller provides electronic temperature sensing in a
UL limit-rated controller with a single sensing probe. The
L7224U controls the circulator, oil or electric burner or
contactor, and boiler temperature.
The L7224U is “Outdoor Temperature Reset” ready,
which is enabled when connected to the W8735Y1000
wireless or W8735S1000 wired Outdoor Reset Kits. This
option is intended for all applications except for tankless
coil systems for domestic hot water.
The L7224U replaces the L8124A, L8124C, L7124U,
L7148A, L7248A,C, L7224A,C, and L8148A controllers
and is intended for residential applications.
The L7224U also complies with 2012 DOE regulations to
ensure efficiency is maximized without interfering with
domestic hot water demands.
IMPORTANT:
Use of Outdoor Temperature Reset on a tank-
less coil application requiring a Low Limit setting
may result in limited system effectiveness and
reduced efficiency.
The L7224U provides status and diagnostic
information through an LED display combined
with LED lights as well as EnviraCOM communi-
cations enabled thermostats and diagnostic
tools to enhance the diagnostic process.
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.

L7224U OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT®CONTROLLER
69-1720EFS—07 2
Accessories (Ordered Separately):
W8735Y1000 Wireless Outdoor Reset Kit
W8735ER1000 Wireless Outdoor Reset Module
C7089R1013 Wireless Outdoor Temperature Sensor
(requires W8735ER1000)
W8735S1000 AquaReset™ Outdoor Reset Kit (includes
50022037-002 Outdoor Reset Module and
C7089U1006 Outdoor Temperature Sensor)
W8735S1008 AquaReset™ Domestic Hot Water Kit
(includes 50022037-005 Domestic Hot Water Module
and 32003971-003 Sensor)
C7089U1006 Outdoor Temperature Sensor (used with the
50022037-002)
32003971-003 Temperature Sensor (used with
50022037-005)
Sensor (See Table 2).
Sensor Well Clamp 121371AA.
120650 Heat Conductive Compound.
Fig. 1. L7224U mounting dimensions in inches (mm).
INSTALLATION
When Installing this Product...
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 Differential to the set-
tings 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 the time of installa-
tion in the text box provided on the cover insert
label.
WARNING
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 L7224U can be mounted in a well mount, horizontal
or vertical position, or flush mounted remote from the well.
IMPORTANT
Immersion well must fit sensing element and
sensor must rest against bottom of well.
Table 1. Wells for L7224U Controller.
Part
Number Spud Size in. (mm) Insertion in. (mm) Insulation in. (mm)
123869A 1/2 (12.7) NPT 3 (76.2) 1-1/2 (38.1)
123870A 3/4 (19.05) NPT 3 (76.2) 1-1/2 (38.1)
Table 2. Sensors for L7224U Controller.
Part Number Length in. (mm) Application
50001464-001 12 (304.8) Well-mounted controls
50001464-003 24 (609.6) Flush-mounted controls
50001464-004 36 (914.4)
50001464-005 48 (1219.2)
M22147B
3/4
(75)
5-11/16
(145)
3/8
(10)
2-5/8 (67)
7-1/8
(181)
6-1/2
(166)
3-13/32 (86)
2x 1/4 (7) x 3/8 (9)
1/16 (2)
1-3/16
(30)
3-1/32
(77)
2-1/16 (53)
1-1/8 (29)
4-1/4 (109)

L7224U OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT®CONTROLLER
3 69-1720EFS—07
New Installation
Order well assemblies separately; refer to 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. See Fig. 1 for mounting dimensions.
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. Identify if installation requires vertical or horizontal
mounting.
7. Remove the well knockout, for either vertical or
horizontal mounting, by carefully prying the
knockout from the back of the case, using a
flat-bladed screw driver. Refer to Fig. 2.
8. Loosen but do not remove the well clamp screw.
9. Fit the case into the well so the clamp on the case
slides over the flange on the well.
10. Securely tighten the clamp screw.
11. Insert the sensor element into the well until it
bottoms. (If necessary, slightly bend the wire inside
the case to hold the sensor against the bottom of
the well.)
12. Turn power ON.
13. Set High Limit, Low Limit and Differentials to the
settings recommended by the boiler OEM. (See
OPERATION section, also refer to INSTALLATION
steps 6 and 7.)
Fig. 2.
Removing horizontal or vertical mounting
knockout.
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 neces-
sary, 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®models) as follows: Fold the
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. 3. Wipe excess compound
from the outer end of the well.
Fig. 3. Position of sensor in immersion well.
Flush-Mounted Aquastat
Replacement
Turn off all power and remove the old controller. Refer to
the cover insert of the old controller 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.
See Fig. 1 and 4 for mounting tab location.
SCREWDRIVER
M22118
KNOCKOUT FOR
HORIZONTAL
MOUNT
KNOCKOUT FOR
VERTICAL MOUNT
SENSOR WIRES
IMMERSION WELL
CLAMP SCREW
IMMERSION
WELL CLAMP
M16120
HEAT-CONDUCTIVE COMPOUND
(OPTIONAL)
CONTROLLER CASE
BOILER
IMMERSION
WELL
SENSOR

L7224U OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT®CONTROLLER
69-1720EFS—07 4
Fig. 4. Location of L7224U flush-mounting tabs and
LEDs.
Well-Mounted Aquastat
Replacement
Turn off all power and remove the old controller. Refer to
the cover insert of the old controller 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 controller 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. 5.
(If desired, distribute the heat-conductive com-
pound in the tube prior to sensor insertion, as
described in New Installation.)
4. Make sure sensor is fully seated to bottom of well
(Fig. 5). Use a small pencil to measure depth of
sensor in well, if necessary.
Fig. 5. Replacement sensor installation.
Replacement Sensor Installation
Turn off all power and carefully disconnect sensor from
circuit board by pulling gently on the connector.
1. Gently pull sensor from thermo well and through cir-
cuit board by pulling on leadwires.
2. Carefully align replacement sensor with hole in
circuit board and guide through Aquastat case and
into well. Refer to Fig. 5.
3. Make sure sensor is fully seated to bottom of well
(see Fig. 5). Use a small pencil to measure depth of
sensor in well, if necessary.
4. Connect sensor to circuit board by pressing
connector on sensor unit into mating connector on
circuit board (refer to Fig. 6).
5. For remote sensors (flush mounted Aquastat) be
sure to use the 121371AA clamp to securely hold
sensor in place. See Accessories.
Fig. 6. Wiring the Outdoor Reset Module and the
Domestic Hot Water Module.
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 9.
WIRING
WARNING
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 controller.
IMPORTANT
The terminals on these Aquastat Controllers are
approved for use with copper wire only.
C1
B1
ZC
L2
LINE
C2
ZR
TX
L1
B2
T
T3
2
1
THERMOSTAT
TERMINALS
ENVIRACOM
TM
TERMINALS
DISPLAY
SENSOR
CONNECTOR
SENSOR HOLES
FUSE
FLUSH MOUNTING TAB (2)
M32197
LED's
TT
B1 ZC C1
SENSOR WIRES
M22026
HEAT-CONDUCTIVE COMPOUND
(OPTIONAL)
BOILER
IMMERSION
WELL
SENSOR
C1
B1
ZC
L2
LINE
C2
ZR
L1
B2
T
T3
2
1
1 2 3 OT OT
C7089U1006
OUTDOOR
SENSOR
W8735Y1000 OR W8735S1000
OUTDOOR RESET MODULE
(W8735S1000 SHOWN)
1 2 3 TS TS
W8735S1008
DOMESTIC HOT
WATER MODULE
32003971-003
TEMPERATURE
SENSOR
M34961