L7224U OIL ELECTRONIC AQUASTAT
®
CONTROLLER
7
69-1720—03
NOTE: Setting the Low Limit above the High Limit less
the High Limit Differential is not allowed as
improper circulator and Zone Control functions
could result.
Anti Short-Cycle Feature
The Anti Short-Cycle feature allows for field selection of a
minimum delay time between burner cycles. Should a call
for heat occur following the end of the previous heat cycle
and before the Anti-Short Cycle delay time is expired, the
circulator will be allowed to run, but the burner will be held
off until the time has elapsed.
NOTE: The Anti Short-Cycle feature is blocked if DHW
demand occurs. DHW demands are serviced
immediately, without any delay.
NOTE: When the Aquastat is connected to the oil pri-
mary and/or thermostat via the EnviraCOM bus,
the Anti Short-Cycle time does not apply to recy-
cle events such as loss of airflow or flame. It
applies only to loss of demand.
ZR-Domestic Hot Water (DHW) Request
The ZR terminal on the L7224U can be selected to
service an indirect water heater heat request. This
parameter is set via the 3 digit display (see Adjusting
Settings section of this document). A heat request via the
ZC terminal will have priority over all other features such
as the Anti-Short Cycle feature or those enabled by the
Outdoor Reset Module (See form69-2235 for more
information).
CHECKOUT
Put the system into operation and observe at least one
complete cycle to make sure that the controller operates
properly. See TROUBLESHOOTING section to use LED
to assist in determining system operation.
TROUBLESHOOTING
When attempting to diagnose system performance,
reference to the LED display can help to identify specific
areas not working properly. The LED display will scroll
Err
, followed by a digit (1-8). Refer to Table 7 for a
description of each error and suggested actions and Table
8 for a troubleshooting guide.
Fig. 9. L7224U single zone connections.
C1
B1
ZC
L2
LINE
C2
ZR
L1
B2
T
T 3
2
1
M22028A
L1
(HOT)
SENSOR
LINE
VOLTAGE
CIRCULATOR
LINE
VOLTAGE
OIL BURNER
RELAY
L2
