31
AquaSmart Boiler Control Manual
75
50
100
125
150
175
200
225
250
275
300
75
50
100
125
150 175 200
225
250
275
300
How a Boiler Control Works
Figure 19 - Cold Start Operation (Low Limit ► OFF)
Figure 20 - Warm Start Operation (Low Limit ► ON) (To maintain domestic hot water temperature)
High Temperature Limit
(Adjustable 100° to 240°F)
Shuts burner off at HIGH LIMIT set point.
High Temperature Differential
(Adjustable 5° to 45°F)
Starts the burner when temperature drops to the
HIGH LIMIT DIFFERENTIAL setting.
Example Shown:
High Limit = 200°
Differential = 20°
During a call for heat, the burner will be
shut off at 200° and be turned back on at
180° (200°-20°). The circulator will
continue to operate until the call for heat
is satisfi ed.
Low Temperature Limit
(Adjustable 100° to 220°F)
Starts the burner at LOW LIMIT
set point.
Low Temperature Differential
(Adjustable 10° to 45°F)
Shuts burner off when temperature rises to
the LOW LIMIT DIFFERENTIAL setting.
High Temperature Limit
(Adjustable 100° to 240°F)
Shuts burner off at HIGH LIMIT set point.
High Temperature Differential
(Adjustable 5° to 45°F)
Starts the burner when temperature drops to the
HIGH LIMIT DIFFERENTIAL setting.
Example Shown:
Low Limit = 140°
Differential = 10°
During the OFF cycle with no call for
heat, the burner is turned on at 140° to
maintain the boiler water temperature
and is shut off at 150° (140°+10°).
Example Shown:
High Limit = 200°
Differential = 20°
During a call for heat, the burner will be
shut off at 200° and be turned back on at
180° (200°-20°). The circulator will
continue to operate until the call for heat
is satisfi ed.