If desired, the pump may be operated continuously during the heating season. Should you
decide to wire the pump in this manner, it should be wired to the same supply circuit as the
boiler to prevent the pump from being turned off while the boiler is still powered.
Thermostat Connection
The thermostat connection is 24 volt AC.
Only connect the thermostat after all
other work is complete, the entire heating system is filled with water and
is thoroughly purged of air.
The thermostat is connected to the terminals T1 and T2 on
the control circuit board (see Fig. 4). In zoned systems, the end switches of all the zone valves
may be connected in parallel and hooked up to the thermostat connection on the control
board. For a typical system (see Fig. 5).
Thermostats described as “Power Stealing” or as “Parasitic Thermostats”
must not be used.
Thermostat Cycle Length and Anticipator
Electronic thermostats typically have provisions for the cycle length, and type of heating
system. The instructions for the thermostat should be followed.
Older thermostats with anticipators should be set to 0.2 amps. Failure to correctly adjust this
setting may result in unsatisfactory comfort conditions, and could result in damage to the
thermostat.
In zoned systems where the thermostat is controlling a zone valve, or circulation pump and not
the boiler, the anticipator should be set to match the current draw of the zone valve being used.
This setting may have to be adjusted slightly to ideally match the boiler control system to the
thermostat, as well as overcome the normal inertia of the radiation system. A setting too low
will be characterized by a short cycle, which does not allow the room temperature to be
satisfied before the boiler shuts down. A setting too high will be characterized by a long cycle,
which allows the room temperature to rise too high before the boiler shuts down. Adjustments
should be made to the setting, if required, but should not exceed 0.1 amps per adjustment.
Temperature Control Setting (Aquastat)
The boiler has a temperature control knob, known as an aquastat on the lower left corner of
the control board. This sets the maximum temperature that the boiler will operate at. The
internal control system monitors the water temperature in the tank and modulates the heating
elements to maintain the water temperature. Note that the setting on the knob only sets the
maximum temperature, it is normal for the boiler to operate at lower temperatures than this
setting at times, this is especially true in the spring and fall when it is not so cold outside.
The
actual temperature setting you need to set it to will be determined by the type of
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