resideo Aquastat L7224 Series User manual

TECHNICIAN’S QUICK REFERENCE GUIDE
69-1957-03
L7224 Series Oil Electronic
Aquastat®Controller
(2012 Compliant)
The following service procedure provides a quick overview
for L7224 Series Controllers. For more information, refer to
forms 69-1720 L7224U Installation Instructions, 66-1202
Wireless Outdoor Reset Installation Instructions, 69-2335
Outdoor Reset Installation Instructions, and 69-2343
Domestic Hot Water Module Installation Instructions. This
control is compatible with both wireless and wired
AquaReset Outdoor Reset Controls.
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.
On the L7224U settings can be adjusted to best fit the
requirements of the application.
Additional settings options are available to define an
outdoor reset curve for those systems requiring Outdoor
Temperature Reset and other adjustable parameters.
IMPORTANT
Outdoor Temperature Reset should be limited to
those systems consisting of a cold start boiler
and may include an indirect tank for domestic hot
water.
Outdoor Temperature Reset should not be used
with tankless coil systems as the low limit
setting required in such systems may limit
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effectiveness and thereby projected increased
efficiency of Outdoor Reset.
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 Ibuttons simultaneously for three seconds.
Press the Ibutton until the feature requiring adjustment is
displayed:
Display Definition
HL_ High Limit.
Hdf High Limit Differential.
LL_ Low Limit.
Ldf Low Limit Differential.
duu ZR input configured as external Domestic Hot
Water (DHW) request (ON/OFF)
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)
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* Settings available for adjustment on the 3-digit display
only if the 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
setting 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 Ibuttons simultaneously
for three seconds. Then push the Ibutton 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 Aquastat®settings, press the Ikey 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.
Pressing the Ibutton twice more 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.
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Table 1. Display readout definitions.
Text Description Display
Err Error Code (if one is present) Err
bT Boiler Temperature bt
HL High Limit 1 HL
HdF High limit differential HdF
LL Low Limit set-point (L7224 only) LL
Ldf Low Limit differential (L7224 only) LdF
tt Local Thermostat Status tt
ttE EnviraCOM Thermostat Status ttE
brn B1 (Burner) output (ON or OFF) brn
Cir C1 (Circulator) output (ON or OFF) Cir
ZC ZC (Zone Control) output (ON or OFF) 2C
Zr ZR (Zone Request) Call for HEAT (ON or
OFF) 2r
duu ZR Configured as Domestic Hot Water
Request (L7224, L7248L only) dvv
ASC Anti Short-Cycle Timeout ASC
bSP Boiler Set-Point 2 bSP
dhc DHW Module Connected 3 (YES or NO) dhc
ot Outdoor Temperature 2 ot
otL Outdoor Temperature Low 2 otL
otH Outdoor Temperature High 2 otH
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1Display shows local setting; not the setting as modified by an
external enviracom control.
2Settings are viewable only if the outdoor reset module and
outdoor temperature sensor are installed and functioning properly.
3Settings are viewable only if the domestic hot water module
and sensor are installed and functioning properly.
Outdoor Reset
The Outdoor Temperature Compensation (OTC) feature
adjusts the target boiler temperature to a point below its
local high limit setting and above the boiler's
condensation temperature by using the EnviraCOM
communication bus to directly adjust the Aquastat set-
point. Should a call for Domestic Hot Water be detected,
the boiler temperature is commanded to return to the High
Limit setting, ensuring a hot water supply is available.
When the Domestic Hot Water demand is met, the Outdoor
Reset feature is once again enabled.
NOTE: In many cases the Outdoor Reset parameters will
not need to be adjusted as their default values
are designed to accommodate mid-Atlantic and
lower New England areas.
btL Boiler Temperature Low 2 btL
bP Boost Period 2 bP
bS Boost Step 2 bS
UUS Warm Weather Shutdown Temperature 2 UUS
Table 1. Display readout definitions. (Continued)
Text Description Display
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L7224 SERIES OIL ELECTRONIC AQUASTAT®CONTROLLER
CAUTION
Possible Equipment Damage
When enabling the Outdoor Reset function, be sure
to refer to the boiler OEM’s instructions for the
lowest return water setting to avoid condensation
in the heat exchanger, which can result in
equipment damage.
Boost
If heat demand is not met within a certain time period
while the boiler is in setback mode (following the Outdoor
Reset curve), a Boost Period is invoked where the boiler
set point is increased by a value called the Boost Step.
Each time the Boost Period elapses and heat demand is
not satisfied, the boiler set-point is again increased by the
Boost Step, up to the maximum setting provided by the
High Limit setting (see Table 3 below).
Table 2. Outdoor Reset Curve Settings and Defaults.
Parameter
Minimum
Value
Maximum
Value Default
High limit 130 °F
(54 °C)
240 °F
(116 °C)
180 °F
(82 °C)
Minimum outdoor
temperature
-40 °F
(-40 °C)
40 °F
(4.4 °C) 0 °F (-18 °C)
Minimum boiler
temperature
80 °F
(27 °C)
180 °F
(82 °C) 130 °F (54 °C)
Maximum outdoor
temperature
30 °F
(-1 °C)
70 °F
(21 °C) 40 °F (4.4 °C)
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L7224 SERIES OIL ELECTRONIC AQUASTAT®CONTROLLER
Fig. 1. Outdoor temperature setback curve with boost.
Warm Weather Shutdown: Aquastat
The Warm Weather Shutdown feature causes the boiler to
shut down when the outdoor temperature exceeds a
specified value. The default Warm Weather Shutdown is
“OFF.”
CAUTION
Zone Panel Settings
In applications with zoning panels having a priority
zone for domestic hot water: Disable the warm
weather shutdown feature on the Aquastat.
As Outdoor Temp reaches the Warm Weather Shutdown
setpoint if enabled), the boiler is kept from cycling and will
only service DHW demands.
Table 3. Boost Settings and Defaults.
Parameter Name
Minimum
Value
Maximum
Value Default
Boost period 5 minutes
(or Off)
30 minutes 10 minutes
Boost step 5 °F
(or Off)
20 °F 10 °F
HIGH LIMIT
BOILER
TEMPERATURE
M29557
MINIMUM BOILER
TEMPERATURE
MINIMUM
OUTDOOR
TEMPERATURE
MAXIMUM
OUTDOOR
TEMPERATURE
OUTDOOR
TEMPERATURE
BOOST
STEP
BOOST
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L7224 SERIES OIL ELECTRONIC AQUASTAT®CONTROLLER
Table 4. LED Error Codes.
Aquastat
Error
Code Cause/Action
EnviraCOM
Alarm
Err1 Aquastat sensor fault; check water sensor. 18
Err2 ECOM fault; check EnviraCOM™ wiring. 18
Err3 Excessive electrical noise or frequency out
of range. Hardware fault; replace
controller.
18, 58
Err4 B1 fault; check B1 wiring/voltage. 64
Err5 Low Line; check L1-L2, 110 Vac. 59
Err6aWarning: Fuse; check ECOM wires, replace
fuse.
92
Err7 Warning: EEPROM, HL, LL, Hdf, Ldf; reset
to default values.
N/A
Err 8bRepeated B1 fault (voltage present at B1
when output is turned off); check B1
wiring/voltage.
25
Err9aWarning: 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.
50, 53, 149
Err 10aWarning: Boost Failure; Boost Mode active
at least once per cycle for the last 60
consecutive cycles. Check Outdoor Reset
curve settings.
150
Err 11aDHW Module/Sensor failure;
communication to DHW Module lost, DHW
Module failure, or temperature sensor
failure. Check EnviraCOM wiring (1, 2, 3),
check sensor wiring.
146, 147,
148
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aWarnings 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 Mod-
ule 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 Out-
door Reset algorithms. The warnings are cleared when each issue
is resolved.
bTo 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
burner is not drawing excessive current. Err 8 condition will keep
repeating if B1 fault is not cleared.
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Table 5. L7224 Controller Operating Sequence.
Action System Response
Thermostat
calls for heat.
Circulator starts when water temperature is above
Low Limit setting (if 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.
Boiler
temperature
exceeds the
High Limit.
Burner is turned off. Burner restarts when the
water temperature 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).
Burner is turned on, Circulator is turned off. Burner
stops when the water temperature exceeds the
Low Limit setting. Power to Zc is removed.
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* Error condition only available when the Outdoor Reset Module is
installed.
Troubleshooting
When attempting to diagnose system performance,
reference the LED display to help identify specific areas
not working properly. The LED display will scroll “err,”
followed by a digit (1-11). See Table 1 for a description of
the error and suggested actions. See below for a
troubleshooting guide.
Error
conditions
1-5.
If an error condition is detected, all outputs except
ZC are shut down. Burner is off. The controller
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 controller has reset the High Limit, Low Limit
and Differential Setting to a default setting and will
continue to run at those settings. Performance of
the system will be degraded.
Error
condition 8.
If the error condition is detected, all outputs
except ZC are shut down. Burner is off.The
controller 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.
Action System Response
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L7224 SERIES OIL ELECTRONIC AQUASTAT®CONTROLLER
Table 6. Troubleshooting Guide.
System
Condition
Diagnostic
Condition Check Action
Boiler is
cold,
house is
cold.
Display is
OFF.
120 Vac system
power.
Turn system power on.
Display is
ON.
TT-LED is
OFF.
24 Vac T-T. No 24 V; replace
controller.
Display is
ON.
TT-LED is
OFF.
24 V present;
disconnect
thermostat, short
T-T.
Boiler starts, check
wiring and thermostat.
Display is
ON.
TT-LED is
ON.
B1 LED is
ON.
120 Vac at B1-
B2.
If no, replace
controller.
If yes, check burner
and wiring.
Display is
ON.
TT-LED is
ON.
Refer to Err on
display.
—
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L7224 SERIES OIL ELECTRONIC AQUASTAT®CONTROLLER
Boiler is
hot,
house is
cold.
Display is
ON.
TT-LED is
ON.
C1 LED is
ON.
120 Vac at C1-
C2.
120 Vac at C1-C2,
check wiring to pump.
Wiring ok, is pump
running? If not,
replace the pump.
If pump is running,
check for trapped air
or closed zone valves.
Display is
ON.
TT-LED is
ON.
C1 LED is
OFF.
ZC LED is
ONa.
Boiler below the
Low Limit
temperature, wait
for boiler to go
above Low Limit
temperature.
—
Display is
ON.
TT-LED is
ON.
ZC LED is
OFFb.
Boiler above LL?
If yes, check for
120 Vac between
ZC and L2.
If no 120 Vac, replace
controller.
If yes, check zone
relays, circulators and
wiring.
System
Condition
Diagnostic
Condition Check Action
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L7224 SERIES OIL ELECTRONIC AQUASTAT®CONTROLLER
aZC LED ON indicates ZC terminal power is OFF.
bZC LED OFF indicates ZC terminal power is ON.
Boiler is
hot, no
hot
potable
water
Display is
ON.
Boiler Demand
signal from the
water heater
(either 120 Vac at
ZR-L2, or 0 Vac
on T-T; depends
on installation
and “duu” setting)
24 Vac on T-T (or
0 Vac on ZR-L2),
check wiring to water
heater
Wiring OK, check the
water heater
“Zr” reads “On”
(or “tt” reads
“On”)
“Or” reads “OFF” but
120Vac on ZR-L2,
replace the control
“duu” setting Set duu to ON if
120 Vac water heater
demand is connected
to ZR
Set duu to OFF if
open/closed water
heater demand is
connected to T-T
Check DHW
Module and DHW
Sensor
DHW Module not
properly connected
and/or DHW Sensor
improperly positioned
System
Condition
Diagnostic
Condition Check Action
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© 2020 Resideo Technologies, Inc. All rights reserved.
This product is manufactured by Resideo Technologies, Inc. and its affiliates.
www.resideo.com
Resideo Technologies, Inc.
1985 Douglas Drive North, Golden Valley, MN 55422
1-800-468-1502
69-1957—03 M.S. Rev. 10-20 | Printed in United States
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