Operation
WATER TEMPERATURE
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MAX. TEMP. |
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Setting The Boiler Temperature
Without the Outdoor Air Temperature Sensor Installed
To set the maximum boiler water temperature, sim- ply turn the Max. Temp. water temperature dial to the desired setting. The control and the boiler will then perform to achieve and maintain the set temperature. The Min. Temp. Knob is the boiler water tempera-
ture minimum, or the lowest temperature the water will go before the unit
With The Outdoor Air Temp - Sensor Installed Maximum boiler temp setting is as described above. The MIN. TEMP. knob in addition to being the
mode setting (on or off) now also has the function of setting the minimum boiler water temperature. This would be the lowest boiler water temperature that you want to have based on the following factors.
1.) Outdoor Air Temperature (OAT)
2.) Domestic Hot Water Use
a.) Hot Water Coil Option
b.) Indirect Hot Water Storage 3.) Overall Volume of the Heating System
Control Board Operation
Aquastat Sensor - This sensor is located in the aqua- stat well on the top of the water jacket. This sensor along with the outdoor air sensor is what the control board uses to regulate the feed rate based on these two observed conditions. (Boiler Temp. & Outdoor Air Temperature)
Outdoor Air Temp. Sensor (OAT) - This sensor is located outside the building (on the north side of the house and out of direct sunlight). The Outdoor Air Sensor is used to perform hot water reset based on out- door air temperatures.
When the OAT sensor is installed, at 20° F. or below (outside temperature), the boiler will operate at the temperature set on the MAX. TEMP. knob. The boiler water temperature will decrease by 1 degree F. for every 1 degree F. in temperature rise (above 20°) of the outdoor air.
NOTE: Pellet Boiler Outdoor Air Reset Operation Graph located on page 25.
The boiler is designed to withstand lower return water temperatures however, extended return temperatures below 140 degrees F can cause condensation in the secondary ash chamber area and also in the venting system, which could cause damage in these areas.
NOTE:
If the system is run at the lower temperature settings, con- ditions of the firebox, boiler tubes, secondary ash chamber and venting should be monitored closely. If conditions show excess condensation, the boiler water minimum tempera- ture will need to be increased until condensation does not occur. You should also consider some form of tempering of the return water system. Discuss this with your plumber.
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