Honeywell L7248A, L7224A User Manual

68-0281-16

L7224A,C; L7248A,C,L Oil and Electric Boiler

Electronic Aquastat

APPLICATION

The L7224A,C and L7248A,C,L 2012 Compliant 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 or electric burner or contactor, and boiler temperature. The L7224/L7248 is “Outdoor Temperature Reset” ready which is enabled when connected to the W8735Y1000 wireless or W8735S1000 wired 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.

Controllers provide electronic

IMPORTANT

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.

Controllers

INSTALLATION INSTRUCTIONS

Use of Outdoor Temperature Reset on a tankless coil application requiring a Low Limit setting will result in reduced system effectiveness and efficiency.

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.

L7224A,C; L7248A,C,L OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT® CONTROLLERS

WARNING

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)

Accessories:

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) W8735S3000 EnviraCOM™ Alarm Module C7089U1006 Outdoor Temperature Sensor (used with the

50022037-002) 32003971-003 Temperature Sensor (used with

50022037-005) Sensor (See Table 2). 120650 Heat Conductive Compound. 121371AA Sensor Well Clamp.

Table 1. Wells for L7224A,C; L7248A,C,L Controllers.

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 L7224A,C and

L7248A,C,L Controllers.

Part N umber

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)

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 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).

IMPORTANT

Immersion well must fit sensing element and sensor must rest against bottom of well.

68-0281—16 2

L7224A,C; L7248A,C,L OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT® CONTROLLERS

SENSOR WIRES

IMMERSION WELL CLAMP SCREW

IMMERSION WELL CLAMP

M16120

HEAT-CONDUCTIVE COMPOUND (OPTIONAL)

CONTROLLER CASE

BOILER

IMMERSION WELL

SENSOR

LINE

THERMOSTAT

TERMINALS

ENVIRACOM

TERMINALS

SENSOR HOLES

FUSE

M32186

SENSOR CONNECTOR

DISPLAY

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. Inser t 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

well holes for horizontal mount models.

3 68-0281—16

L7224A,C; L7248A,C,L OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT® CONTROLLERS

WARNING

SENSOR WIRES

M22026

HEAT-CONDUCTIVE COMPOUND (OPTIONAL)

BOILER

IMMERSION WELL

SENSOR

LINE

THERMOSTAT

TERMINALS

ENVIRACOM

TERMINALS

DISPLAY

SENSOR CONNECTOR

SENSOR HOLES

FUSE

RELAYS

M32187

LINE

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

WIRING

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 circuit board by pulling on leadwires.

3. Carefully align replacement sensor with hole in circuit 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 connector on sensor unit into mating connector on circuit board (See Fig. 5).

6. For remote sensors (flush-mounted Aquastat Controllers) 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.

Fig. 5. Circuit board, showing sensor connection and

well holes for vertical mount models.

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 Tab l e 1 0.

68-0281—16 4

Fig. 6. Wiring the Outdoor Reset Module and the

Domestic Hot Water Module.

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.

L7224A,C; L7248A,C,L OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT® CONTROLLERS

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 an 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.

Display Definition

HL_ High Limit.

Hdf High Limit Differential.

LL_ Low Limit. (L7224A, C)

Ldf Low Limit Differential (L7224A, C)

ELL External Low Limit (L7248L only)

duu ZR input configured as external Domestic Hot

Water (DHW) request (ON/OFF) (L7224A,C/ L7248L)

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)

tPL** Thermal Purging Limit Temperature (°F or °C),

“OFF” if disabled

tPt** Termal Purging Time Delay (minutes), shown

only if tPL is enabled

PC Pump Cycling (ON / OFF)

F-C Temperature units (°F or °C)

* Settings available for adjustment on the 3-digit display

only if a W8735Y1000 or W8735S1000 Outdoor Reset Kit is installed.

**Settings available for adjustment only when the

W8735Y1000 or W8735S1000 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.

5 68-0281—16

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