Honeywell L7224 User Manual

L7224 Series
Oil Electronic

Aquastat® Controller

TECHNICIAN’S QUICK REFERENCE GUIDE

The following service procedure provides a quick overview for
L7224 Series Controllers. For more information, refer to form
69-1384.

On the L7224U the High Limit, High Limit Differential, Low Limit,
and Low Limit Differential can be adjusted to the settings
recommended by the boiler OEM.

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
simultaneously for three seconds. Press the I button until the
feature requiring adjustment is displayed:

• HL—High Limit.

• LL—Low Limit.

• Ldf—Low Limit differential.

• F - C—°F or °C.

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
control will automatically return to the READ 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 buttons 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 (HL) High Limit is displayed,
followed by a three-digit number, i.e., 220, followed by °F or °C.

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L7224 SERIES

Pressing the I button again will display the LL (Low Limit) followed
by a three-digit number and the corresponding degree designator.
See the table below for an 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.

Display

Text Description

bt

f
c

Boiler Temperature

High LimitHL

Low LimitLL

High Limit DifferentialHdf

Low Limit DifferentialLdf

Local Thermostat Statustt

Enviracom Thermostat Statustte

Burner Statusbrn

Circulator Statuscir

Zone ControlZc

Zone RequestZr

Error Codeerr

Degrees Fahrenheit

Degrees Celsius

Shows

M22149

Table 1. LED Error Codes

Error Code Cause/Action

Err1 Sensor fault; check sensor.
Err2 ECOM fault; check EnviraCOM. wiring.
Err3 Hardware fault; replace control.
Err4 B1 fault; check B1 wiring/voltage.
Err5 Low Line; Check L1-L2, 110 Vac.
Err6 Fuse; Check ECOM wires, Replace fuse.
Err7 EEPROM, HL, LL, Hdf, Ldf, Reset to default values.
Err8 Repeated B1 fault (voltage present at B1 when

output is turned off); check B1 wiring/voltage.

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