126 Bailey Road, North Haven, CT 06473 • Phone (203) 776-0473 • FAX (203) 764-1711 •
www.hydrolevel.com
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LIMITED MANUFACTURER’S WARRANTY
We warrant products manufactured by Hydrolevel Company to be free from defects in
material and workmanship for a period of two years from the date of manufacture or
one year from the date of installation, whichever occurs first. In the event of any claim
under this warranty or otherwise with respect to our products which is made within
such period, we will, at our option, repair or replace such products or refund the pur-
chase price paid to us by you for such products. In no event shall Hydrolevel Company
be liable for any other loss or damage, whether direct, indirect, incidental or conse-
quential. This warranty is your EXCLUSIVE remedy and shall be IN PLACE OF any other
warranty or guarantee, express or implied, including, without limitation, any warranty
of MERCHANTABILITY or fitness for a particular purpose. This warranty may not be
assigned or transferred and any unauthorized transfer or assignment thereof shall be
void and of no force or effect.
HOW THE OUTDOOR SENSOR WORKS
OUTDOOR TEMPERATURE RESET
The outdoor reset feature monitors outdoor temperature to continuously adjust the boiler water to the minimum
temperature required to satisfy the heat demand. The feature is activated automatically when the sensor is wired to
the OR and C spade connects on the Fuel Smart HydroStat. When connected, Outdoor Reset overrides the
Thermal Targeting temperature reset method which is built into the Fuel Smart HydroStat. The display will toggle
between boiler temperature (8 seconds) and outdoor temperature (2 seconds). If the sensor becomes damaged or
disconnected, the control will automatically revert back to the Thermal Targeting reset method. The display will no
longer toggle outdoor temperature.
RESET RATIO
The Fuel Smart HydroStat control’s Outdoor Reset feature uses a reset ratio method to control the boiler
temperature. The reset ratio determines how much the boiler temperature is adjusted for changes in outdoor
temperature. A reset ratio of 2.0 means that for each 1 degree increase in outdoor temperature, the boiler
temperature will decrease 2 degrees. Conversely, for each 1 degree drop in outdoor temperature, the boiler
temperature will increase 2 degrees. The control adds 10 degrees to the calculated reset temperature and
provides a 20 degree differential for burner operation. So, if the control calculates a reset temperature of 150°F, it
will set a target temperature of 160°F. It will then allow the burner to fire up to 160°F and draw down to
140°F before re-firing. This operation will maintain the desired average temperature of 150°F. You can check the
current target temperature at any time, by pressing the Test/Settings button in 4 short intervals.
THERMAL BOOST
To insure that the heating system always satisfies a call for heat, the Fuel Smart HydroStat control is equipped
with a thermal boost feature. If the thermostat is not satisfied thirty minutes after the boiler reaches the reset
temperature, the control will boost the reset temperature by 10 degrees. It will continue to boost at 30 minute
intervals until the call is satisfied. Once the call is satisfied, the control reverts to normal operation, utilizing the
calculated reset temperature.
OS100 070218
