Dunkirk Q90-200 Series II - Manual (Page 38)

38
15 - TROUBLESHOOTING
High Limit Control and LWCO
LED Legend and LWCO Test Button
1
HI TEMP illuminates when boiler water temperature
reaches high limit setting. Remains lit until water
temperature falls 10°F. Limit prevents burner operation
while this LED is on.
2
LWCO ACTIVE Indicates low water cut-off function is
active. When control is installed with Electro-well, LED is
on at all times when control is powered. If the control is
installed with a well other than Electro-well, LED will not
illuminate indicating the control is not providing low water
cutoff 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.
!
3
LWCO LOW WATER Illuminates if boiler is in low water
condition. Control will prevent burner operation during this
condition.
Important: System must be checked by qualified service
agency prior to resuming operation.
4
ECONOMY ACTIVE Indicates that thermal targeting
function is active and control reduces boiler temperature
to conserve fuel. Economy feature is activated using the
ECONOMY dial.
5 ECONOMY TARGET When feature is active, control
continually sets target temperatures below high limit
setting to maximize fuel efficiency. When boiler reaches
target temperature, LED illuminates and burner shuts
down. Boiler water continues to circulate and het the
house as long as thermostat call continues. LED stays lit
until boiler temperature drops below differential at which
point boiler will be allowed to fire again.
Note: LED illuminates regularly during normal boiler
operation.
6
PURGE Control is purging latent heat from boiler and
will not fire until temperature drops to 135°F.
7
LWCO To Test LWCO: Press and hold TEST button. Red
Low Water light will illuminate and burner circuit will de-
energize.
Figure 21 - LED Legend