Honeywell L7248A,C,L Thermostat User Manual

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L7224A,C; L7248A,C,L

Oil Electronic

Aquastat Controllers

INSTALLATION INSTRUCTIONS

APPLICATION

SPECIFICATIONS

The L7224A,C and L7248A,C,L 2012 Compliant Oil

Electronic Aquastat^®Controllers provide electronic

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.

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.

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.

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.

L7224/L7248 Aquastat Controllers are intended for use

in residential-type applications.

IMPORTANT

Use of Outdoor Temperature Reset on a tank-

less 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.

8-0281EFS-05

L7224A,C; L7248A,C,L OIL ELECTRONIC AQUASTAT^®CONTROLLERS

Accessories:

INSTALLATION

W8735Y1000 Wireless Outdoor Reset Kit

W873ER1000 Wireless Outdoor Reset Module

C7089R1013 Wireless Outdoor Temperature Sensor

When Installing this Product...

1. Read these instructions carefully. Failure to follow

them could damage the product or cause a

hazardous condition.

(

requires W8735ER1000)

W8735S1000 AquaReset™ Outdoor Reset Kit (includes

0022037-002 Outdoor Reset Module and

C7089U1006 Outdoor Temperature Sensor)

W8735S1008 AquaReset™ Domestic Hot Water Kit

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.

(

includes 50022037-005 Domestic Hot Water Module

and 32003971-003 Sensor)

W8735S3000 EnviraCOM™ Alarm Module

C7089U1006 Outdoor Temperature Sensor (used with the

0022037-002)

2003971-003 Temperature Sensor (used with

0022037-005)

Sensor (See Table 2).

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.

4,000,485-016 1/4 in. (6.35 mm) diameter, 1-1/4 in.

(31.75 mm) long glass cartridge Fuse, 1A, Slow-Blow.

20650 Heat Conductive Compound.

21371AA Sensor Well Clamp.

7. Record the High Limit setting at time of installation

in the text box provided on the cover insert label.

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

Part

Spud Size

in. (mm)

Insertion Insulation

in. (mm) in. (mm)

1-1/2 (38.1)

WARNING

Number

Electrical Shock Hazard.

Can cause severe injury, death or property

damage.

23869A 1/2 (12.7) NPT 3 (76.2)

23870A 3/4 (19.05) NPT 3 (76.2)

Disconnect power supply before beginning

installation to prevent electrical shock or

equipment damage.

Table 2. Sensors for L7224A,C and

L7248A,C,L Controllers.

Mounting

Length in.

(mm)

Part Number

Application

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.

0001464-001

0001464-003

0001464-004

0001464-005

12 (304.8) Well-mounted controls

24 (609.6) Flush-mounted controls

36 (914.4)

48 (1219.2)

75)

(

-1/8

181)

(

-1/2

166)

(

-11/16

145)

(

-1/32

77)

1-3/16

(30)

(

10)

-1/8 (29)

-1/16 (53)

-5/8 (67)

1/16 (2)

-1/4 (109)

3-13/32 (86)

x 1/4 (7) x 3/8 (9)

M22147B

Fig. 1. L7224A,C; L7248A,C,L mounting dimensions in inches (mm).

68-0281EFS—05

L7224A,C; L7248A,C,L OIL ELECTRONIC AQUASTAT^®CONTROLLERS

IMPORTANT

Immersion well must fit sensing element and

sensor must rest against bottom of well.

SENSOR WIRES

CONTROLLER CASE

BOILER

New Installation

IMMERSION

WELL

SENSOR

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.

HEAT-CONDUCTIVE COMPOUND

OPTIONAL)

(

Turn off all power and drain the boiler, if applicable.

If no tapping is provided, prepare properly sized and

threaded tapping near the top of the boiler.

IMMERSION

WELL CLAMP

M16120

Sparingly coat the well threads with pipe dope.

IMMERSION WELL

CLAMP SCREW

NOTE: Do not attempt to tighten by using the case

as a handle.

Fig. 2. Position of sensor in immersion well.

Install the well in the boiler tapping and tighten

securely.

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.

Refill boiler and check for water leakage.

Loosen but do not remove the well clamp screw.

Fit the case into the well so the clamp on the case

slides over the flange on the well.

Securely tighten the clamp screw.

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 bot-

tom of the well.)

0. Turn power ON.

1. Set High Limit, Low Limit and Low Limit Differential

to the settings recommended by the boiler OEM.

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.

(

See OPERATION section.) (See INSTALLATION

steps 6 and 7.)

2. 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

Loosen, but do not remove, the well clamp screw on

the side of the control case.

Position immersion well clamp snugly over the

flange of the adapter and tighten the clamp screw.

Insert the sensor into the well as shown in Fig. 2 or

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.

. (See Replacement Sensor Installation section for

details.)

If the well is not a snug fit on the sensor, use the

heat-conductive compound (furnished with

_T_R_A_D_E_L_I_N_E® models) as follows: Fold the

THERMOSTAT

TERMINALS

DISPLAY

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.

FUSE

L I N E

SENSOR

ENVIRACOM

SENSOR HOLES

TERMINALS

CONNECTOR

M32186

Fig. 3. Circuit board, showing sensor connection and

well holes for horizontal mount models.

68-0281EFS—05

L7224A,C; L7248A,C,L OIL ELECTRONIC AQUASTAT^®CONTROLLERS

WIRING

SENSOR WIRES

BOILER

WARNING

Electrical Shock Hazard.

IMMERSION

WELL

SENSOR

Can cause serious injury or death.

Disconnect power supply before making wiring

connections to prevent electrical shock or

equipment damage.

HEAT-CONDUCTIVE COMPOUND

OPTIONAL)

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.

(

M22026

Fig. 4. Replacement sensor installation.

IMPORTANT

The terminals on these Aquastat Controllers are

approved for use with copper wire only.

Replacement Sensor Installation

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.

Turn off all power and:

Carefully disconnect sensor from circuit board by

pulling gently on the connector.

Gently pull sensor from thermo well and through cir- Refer to Fig. 6 for Connections for the optional Outdoor

cuit board by pulling on leadwires.

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.

Carefully align replacement sensor with hole in cir-

cuit board and guide through Aquastat case and

into well. (See Fig. 5).

Make sure sensor is fully seated to bottom of well

(

See Fig. 4). Use a small pencil to measure depth of

0022037-002

sensor in well, if necessary.

OUTDOOR

RESET MODULE

Connect sensor to circuit board by pressing con-

nector on sensor unit into mating connector on cir-

cuit board (See Fig. 5).

For remote sensors (flush-mounted Aquastat Con-

trollers) be sure to use 121571AA Clamp (see

Accessories) to securely hold sensor in place.

1 2 3 OT OT

C7089U1006

OUTDOOR

SENSOR

THERMOSTAT

TERMINALS

ENVIRACOM

TERMINALS

0022037-005

DOMESTIC HOT

WATER MODULE

2 3 TS TS

DISPLAY

2003971-003

TEMPERATURE

SENSOR

M29651

SENSOR

CONNECTOR

Fig. 6. Wiring the Outdoor Reset Module and the

Domestic Hot Water Module.

RELAYS

SENSOR HOLES

FUSE

OPERATION

General

M32187

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.

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

Table 10.

For boilers that do include a remotely (flush) mounted

control, the wiring may be completed with conduit or

routed behind the boiler sheet metal.

68-0281EFS—05

L7224A,C; L7248A,C,L OIL 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.

Table 3. Adjustable Features.

Display

HL_

Hdf

Definition

High Limit.

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”.

High Limit Differential.

LL_

Low Limit. (L7224A, C)

Ldf

Low Limit Differential (L7224A, C)

External Low Limit (L7248L only)

ELL

duu

The overall range of the High Limit is from 130 °F to

40 °F (54 °C to 116 °C). Select devices may have

ZR input configured as external Domestic Hot

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

L7248L)

different ranges. Some models have limited ranges on the

High Limit setpoint; this limited range is listed on the

device label.

ASC

otL*

otH*

btL*

bP*

Anti Short-Cycle Timeout (seconds); “OFF” is

disabled.

Some models also have a Low Limit and Low Limit

Differential adjustment. The range of the Low Limit is from

Outdoor Temperature Low (minimum)

parameter for the outdoor reset curve (°F or °C)

110 °F to 220 °F (43 °C to 104 °C). Select devices may

have different ranges.

Outdoor Temperature High (maximum)

parameter for outdoor reset curve (°F or °C)

The Zr setting can be set to DHW, Zoning, or for tankless

coil applications depending on the L7224/L7248.

Boiler Temperature Low (minimum) parameter

for outdoor reset curve

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

Boost Period (minutes). “OFF” is displayed if

Boost is inactive

bS*

Boost step (°F or °C) shown only if Boost is

active (bP=ON)

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

UUS*

tPL**

tPt**

Warm Weather Shutdown Temperature

(

°F or °C)

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

OFF” if disabled

(

-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.

Termal Purging Time Delay (minutes), shown

only if tPL is enabled

Pump Cycling (ON / OFF)

Temperature units (°F or °C)

F-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.

The L7224A,C and L7248A,C,L are designed for use with

4 Vac electronic and electromechanical thermostats or

EnviraCOM™ enabled thermostats, and have screw-type

terminals for easy field connection.

Adjusting Settings

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.

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:

Display

In the RUN mode, the Aquastat will flash “bt” (boiler temp)

followed by the temperature (i.e., 220), followed by °F or

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.,

20, 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.

68-0281EFS—05

L7224A,C; L7248A,C,L OIL ELECTRONIC AQUASTAT^®CONTROLLERS

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).

Table 4. Display readout definitions.

Text

Err

Description

Display

2. High Limit: Boiler temperature went above the High

Limit setting and has not dropped below the High

Limit setting (minus the Differential).

Error Code (if one is present)









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).

Boiler Temperature

HdF

_H_i_g_h_L_i_m_i_t1



High Limit Differential





















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.

Low Limit (L7224 only)

Ldf

Low Limit Differential (L7224 only)

Local Thermostat Status

