COPPER BRUTE II (500 - 2000) | Page 43 |
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minimum amount of time before turning on the next stage. After the minimum time delay between stages has expired, the control examines the control error to determine when the next stage is to fire. The control error is determined using PID logic.
Proportional compares the actual operating sensor temperature to the boiler target temperature. The colder the temperature, the sooner the next stage is turned on.
Integral compares the actual operating sensor temperature to the boiler target temperature over a period of time.
Derivative determines how fast or slow the operating sensor temperature is changing. If the temperature is increasing slowly, the next stage is turned on sooner. If the temperature is increasing quickly, the next stage is turned on later, if at all.
Boiler Mass (BOIL MASS) – The boiler mass setting allows the installer to adjust the control to the thermal mass of different types of heat sources used. The boiler mass setting automatically determines the interstage differential, interstage delay on, interstage delay off, minimum on time and minimum off time of the stages when PID staging is used. A higher thermal mass setting provides slower staging, while a lower thermal mass setting provides faster staging. Copper Brute II boilers and water heaters are
6.4.3 Boiler Minimum (BOIL MIN)
The minimum boiler setting (BOIL MIN) is the
Figure 29. Temperature Control Min & Max.
lowest water temperature that the control is allowed to use as a target temperature. During mild conditions, if the control calculates a target temperature that is below this setting, the target temperature is adjusted to at least the minimum setting. During this condition, if the unit is operating, the MIN segment turns on in the LCD while the target temperature or operating sensor temperature is viewed. For Copper Brute II units, this must be set no lower than 120°F (49°C) to protect the unit
from condensing on the heat exchanger (see Figure 29).
6.4.4 Boiler Maximum (BOIL MAX)
The boiler maximum (BOIL MAX) is the highest water temperature that the control is allowed to use as a target temperature. If the control does target BOIL MAX, and the boiler outlet sensor is near the BOIL MAX temperature, the MAX segment turns on in the LCD while the target, inlet, outlet or supply temperature is viewed (see Figure 29).
6.4.5Boiler Target Temperature
The target temperature is determined from
the mode of operation. The control displays the temperature that is currently trying to maintain at the operating sensor as BOIL TARGET in the View menu. The operating sensor for modes 1, 3 and 4 is the outlet sensor (on the Copper Brute II). The operating sensor for modes 2 and 5 is the supply sensor (in the system or primary loop). If the control does not presently have a requirement for heat, it displays “- -
6.4.6 Pump Operation
The pump terminals (Pmp Pmp) are energized with 24 VAC to control a field supplied pump contactor. During setpoint operation (modes 1 and 2), the terminals are energized whenever there is a heat demand. During dedicated DHW operation (mode 3), the terminals are energized whenever there is an internal heat demand. During outdoor reset (modes 4 and 5), the terminals are energized whenever there is either a heat demand and the control is not in Warm Weather Shut Down (WWSD), or whenever there is a setpoint demand. During WWSD, if the pump has not operated at least once every 70 hours, the control energizes the terminals for 10 seconds. This minimizes the possibility of the pump seizing during a long period of inactivity. During External Boiler Operation (mode 6), the pump contact closes whenever there is a heat demand.
Boiler Purge (PUMP DLY) – After a demand is satisfied, the control continues to operate the pump for a period of time. The length of time that the pump continues to run is based on the pump delay setting. Once the last stage of the control turns off, the control keeps the pump contacts energized for
