Install Instructions
47
EMP
Installation & Service Manual
109529-03 - 11/19
LWCO TEST LCO
The red Low Water light should illuminate and the 
burner circuit (B1 and B2) should de-energize. 
NOTE: The control must be installed with a Hydrolevel 
Electro-Well
TM
 for low water cut-off functionality.
To View Current Settings: Press and release the Test/
Settings Button in short intervals to sequentially 
display the following settings:
HIGH LIMIT SETTING HL
▼
LOW LIMIT SETTING LL
▼
ECONOMY SETTING ECO
▼
CURRENT TARGET TEMPERATURE 000
The display will return to boiler temperature (default) if 
Test/Settings Button is not pressed for 5 seconds.
  WARNING
 Allow the boiler to fully cool before adding water.
  e. ECONOMY ACTIVE Indicates that   
 the Thermal Targeting function is active 
   and the Fuel Smart HydroStat will reduce 
   boiler temperature to conserve fuel. The 
   Economy feature is activated using the 
   ECONOMY dial. (See “How Thermal   
   Targeting Works” for more information).
  f. ECONOMY TARGET When the   
   Economy feature is active, the Fuel   
   Smart HydroStat continually sets   
   target temperature below the high   
   limit setting to maximize fuel     
 efficiency. When the boiler water   
   reaches the target temperature, the LED 
   illuminates and the burner will shut   
   down. The boiler water will continue   
   to circulate and heat the house as long as 
 the thermostat call continues. The LED will 
   stay lit until the boiler temperature   
   drops below the differential set point   
   at which point the boiler will be allowed to 
   fire again. See Differential explanation.
  NOTE: This LED illuminates regularly during 
  normal boiler operation.
  g. 7 TEST/TESTING Button
   To Test Low Water Cut-Off: Press   
   and hold the Test/Settings button for 5 
   seconds. The display will read LCO.
9 Operating (continued)
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