SETTING THE CONTROL
3
IMPORTANT: The outdoor sensor must be plugged in prior to setting the control.
SETTING WARM WEATHER SHUTDOWN
The warm weather shutdown feature prevents the boiler from providing space heating when the outside tempera-
ture reaches a level that you select. Available settings range from OFF or 40°- 70°F. The boiler will still operate to
satisfy a call for domestic hot water. The factory default setting for the warm weather shutdown is 70°F.
To set the desired warm weather shutdown temperature:
Press and hold the TEST/SETTING BUTTON and simultaneously adjust the ECONOMY dial to the desired setting.
To turn the feature off – which will allow space heating regardless of outdoor temperature – press and hold the
TEST/SETTING BUTTON and simultaneously turn the ECONOMY dial fully counter-clockwise. Release the
TEST/SETTING BUTTON. Be sure to reset the ECONOMY dial to the correct setting. Any time the outdoor temp
exceeds the WWSD setpoint, the display will toggle boiler temperature (8 seconds), outdoor temperature (2 sec-
onds), and OFF (2 seconds).
SETTING THE OUTDOOR RESET
The outdoor reset will regulate the boiler’s temperature based on the temperature outside. On cold days, the boiler
will run at higher temperatures to meet the heating load in the house. On warmer days, the boiler will run cooler to
save energy while still meeting the heating needs of the house. The HydroStat control uses a Reset Ratio to calcu-
late and maintain the proper boiler temperature.
To set the desired outdoor Reset Ratio:
1. Determine the Reset Ratio using the table below:
a. Locate the Outdoor Design Temperature for the system on the bottom of the Reset Ratio Chart below.
Round down to the next lowest number.
b. Locate the Boiler Design Temperature (supply temperature needed to meet heating load at the Outdoor
Design Temperature) on the left of the Reset Ratio Chart below.
2. Adjust the ECONOMY dial on the Fuel Smart HydroStat control to the Reset Ratio determined by the intersec-
tion of a. and b. above.
Example:
For a house located in Springfield MA (Design Temperature of 0°F) with baseboard heat
(that was sized for the house based on the 180°F baseboard rating), the reset ratio is 1.50.
220
1.50
1.50
1.50
1.50
1.75
1.75
1.75
2.00
2.00
2.25
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
215
1.25 1.50 1.50 1.50 1.50 1.75 1.75 1.75 2.00 2.25 2.25 2.50 2.50 2.50 2.50 2.50 2.50 2.50
210
1.25 1.25 1.50 1.50 1.50 1.50 1.50 1.75 2.00 2.00 2.25 2.50 2.50 2.50 2.50 2.50 2.50 2.50
205
1.25 1.25 1.25 1.50 1.50 1.50 1.50 1.75 1.75 2.00 2.25 2.25 2.50 2.50 2.50 2.50 2.50 2.50
200
1.25 1.25 1.25 1.50 1.50 1.50 1.50 1.75 1.75 2.00 2.00 2.25 2.50 2.50 2.50 2.50 2.50 2.50
195
1.00 1.25 1.25 1.25 1.50 1.50 1.50 1.50 1.75 1.75 2.00 2.25 2.25 2.50 2.50 2.50 2.50 2.50
190
1.00 1.00 1.25 1.25 1.25 1.50 1.50 1.50 1.75 1.75 2.00 2.00 2.25 2.50 2.50 2.50 2.50 2.50
185
1.00 1.00 1.00 1.25 1.25 1.25 1.25 1.50 1.50 1.75 1.75 2.00 2.25 2.50 2.50 2.50 2.50 2.50
180
1.00 1.00 1.00 1.00 1.25 1.25 1.25 1.50 1.50 1.50 1.75 2.00 2.00 2.25 2.50 2.50 2.50 2.50
175
1.00 1.00 1.00 1.00 1.25 1.25 1.25 1.50 1.50 1.50 1.75 1.75 2.00 2.25 2.50 2.50 2.50 2.50
170
1.00 1.00 1.00 1.00 1.00 1.25 1.25 1.25 1.50 1.50 1.50 1.75 1.75 2.00 2.25 2.50 2.50 2.50
165
0.75 1.00 1.00 1.00 1.00 1.00 1.00 1.25 1.25 1.50 1.50 1.50 1.75 2.00 2.25 2.50 2.50 2.50
160
0.75 0.75 0.75 1.00 1.00 1.00 1.00 1.25 1.25 1.25 1.50 1.50 1.75 1.75 2.00 2.25 2.50 2.50
155
0.75 0.75 0.75 0.75 1.00 1.00 1.00 1.00 1.25 1.25 1.25 1.50 1.50 1.75 2.00 2.25 2.50 2.50
150
0.75 0.75 0.75 0.75 0.75 1.00 1.00 1.00 1.00 1.25 1.25 1.50 1.50 1.75 1.75 2.00 2.50 2.50
145
0.75 0.75 0.75 0.75 0.75 0.75 0.75 1.00 1.00 1.00 1.25 1.25 1.50 1.50 1.75 2.00 2.25 2.50
140
0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 1.00 1.00 1.00 1.25 1.25 1.50 1.50 1.75 2.00 2.50
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
Refer to the Fuel Smart HydroStat instructions for other control settings.
RESET RATIO CHART
O U T D O O R D E S I G N T E M P E R A T U R E
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