Dunkirk EXCELSIOR EXB4075 Installation, Operation & Maintenance Manual page 41

Figure 36 - LED Legend
1
TEMP
ACTIVE Indicates Limit Control is
powered and temperature function is active.
2
TEMP
HI TEMP Illuminates when boiler water
temperature reaches high limit setting. Remains
lit until water temperature falls 10°F. Limit control
prevents burner operation while this LED is on. See
Differential explanation page 39.
3
LWCO
ACTIVE Indicates low water cut-off
(LWCO) function of limit control is active. Boiler
is factory equipped with Hydrolevel electro-well,
enabling control's low water cut-off function. LED will
be on at all times when control is powered.
Important: If control well is replaced with a well
other than Electro-Well, LED will not illuminate
indicating control is not providing low water cut-off
functionality.
!
WARNING
Burn and scald hazard. Do not add water until boiler
has fully cooled. Failure to follow these instructions
could result in death or serious injury.
4
LWCO
LOW WATER Illuminates if boiler is in
low water condition. Limit control will prevent burner
operation during this condition.
Important: System must be checked by a qualified
service agency prior to resuming operation.
5
ECONOMY
ACTIVE Indicates thermal targeting
function is active and limit control will reduce boiler
temperature to conserve fuel. Economy feature is
activated using the Economy dial. See "How Thermal
Targeting Works" this page.
16 - OPERATING THE BOILER - SYSTEM START-UP
6
ECONOMY
TARGET Economy feature is active,
limit control continually sets target temperatures
below high limit setting to maximize fuel efficiency.
When boiler water reaches target temperature, LED
illuminates and burner shuts down. Boiler water will
continue to circulate and heat the house as long as
thermostat call continues. LED will stay lit until boiler
temperature drops below differential set point at
which point boiler will be allowed to fire again.
Note: LED illuminates regularly during normal boiler
operation.
7
TEST/SETTINGS Button
To Test Low Water Cut-Off: Press and hold Test/
Settings button for 5 seconds. Display will read LCO.
LWCO TEST
Red Low Water light should illuminate and burner circuit
(B1 and B2) should de-energize. Note: Control must be in-
stalled with Electro-Well for low water cut-off functionality.
To View Current Settings: Press and release Test/
Settings button in short intervals to sequentially display the
following settings:
Display will return to boiler temperature (default) if Test/
Settings button is not pressed for 5 seconds.
41
LCO