Troubleshooting - High Limit Control And Lwco - UTICA BOILERS UB90-50 Installation, Operation & Maintenance Manual

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 below high limit setting. Limit
prevents burner operation while this LED is on.
2
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
LOW WATER Illuminates if boiler is in low water
condition. Control will prevent burner operation during this
condition.
Important: System must be checked by qualifi ed service
agency prior to resuming operation.
4
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
TARGET When feature is active, control continually
sets target temperatures below high limit setting to
maximize fuel effi ciency. When boiler reaches target
temperature, LED illuminates and burner shuts down.
Boiler water continues to circulate and heat 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 fi re again.
Note: LED illuminates regularly during normal boiler
operation.
6
PURGE Control is purging latent heat from boiler and
will not fi re until temperature drops to 135°F.
7
TEST/SETTING to Test LWCO: Press and hold TEST
button. Red Low Water light will illuminate and burner
circuit will de-energize.

TROUBLESHOOTING - HIGH LIMIT CONTROL AND LWCO

Figure 27 - LED Legend
50