Bradford-White Corp Copper Brute II Hydronic Boiler Manual De Usuario

Page 43

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.

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 low-mass 
appliances, and therefore, should be used with the 

lower thermal mass setting. Set BOIL MASS to “1”.

6.4.3  Boiler Minimum (BOIL MIN)
The minimum boiler setting (

BOIL MIN) is the 

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

).

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

).

6.4.5  Boiler 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 “- - -” in the LCD. 

There is no target temperature generated in mode 6 

(external controller mode).

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.

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