Bradford White BWCH Operations Instructions download pdf (Page 39)

Page 39

COPPER BRUTE II (500 - 2000)

Figure 27. Temperature Control Target Temperature

Graph.

delay setting of 5 minutes. See Section 6.4.6 for more

information.

NOTE: In modes other than mode 6, the pump will

run continuously if the “HtD” and “ComD” terminals

are jumpered and not connected to a zone valve or

pump end switch, or other “contact closure” device

to indicate when the heat demand in the system is

satised. The pump will never run, and the boiler will

never re, if the jumper is removed and the terminals

left empty.

OUTDOOR RESET (modes 4 and 5): Outdoor

reset adjusts the target temperature based on the

outdoor air temperature and reset ratio. The reset ratio

is determined from the Boiler Start, Boiler Design,

Outdoor Start and Outdoor Design settings.

HEAT DEMAND – For heat demand to exist,

there must be continuity between the Com D (common

demand) and Ht D (heat demand) terminals. The

Copper Brute II ships with a jumper between these

terminals.

The control also evaluates the sensor(s) installed

in the system. If the control is not in warm weather

shutdown (WWSD), and the sensor(s) are below the

target temperature, the “Dem” segment is turned on in

the display. The control energizes the pump (on pump

mounted boilers) and energizes both “PMP” terminals.

The pump symbol appears in the display (see Figures

25 and 26). The control then operates the stages to

maintain the setpoint temperature.

Boil Start (Boiler Start): The BOIL START

temperature is the theoretical boiler supply

temperature that the heating system requires when the

outdoor air temperature equals the OUTDR START

temperature setting.

EXAMPLE 1

DHW (Mode 3) Programming. For domestic

hot water systems up to 175°F / 79°C, use mode 3 as

described below.

Step 1: Install the additional sensor into the

storage tank, wiring it to “SC2” and “SUPS” terminals

on the eld wiring panel (Figure 23).

Step 2: Press the three programming buttons

to enter ADJUST mode (Figure 25). Press ITEM to

select the programming item, and the arrow keys to

adjust the setting. TARGET TANK is desired tank

temperature. Recommended settings with a desired

tank temperature of 125°F:

Example DHW Programming

Item F° C°

MODE 3 3

BOIL TARGET 140°F 60°C

TARGET TANK 125°F 52°C

DIFF TANK 2°F 1°C

BOIL MASS 1 1

DIFF 2°F 1°C

DLY 5:00 5:00

F° F° °C

Step 4: See Section 6.4.11 Limit Controls.

Set both high limits 25°F / 14°C higher than BOIL

TARGET to allow for temperature rise across heat

exchanger. Manual high limits on water heaters have

a maximum 200°F / 93°C setting. (If water must be

at 175°F / 79°C or higher with a volume water heater

model, use mode 1. For volume water applications

exceeding 200°F / 93°C, contact the factory.)

Fine tuning: For faster staging, increase BOIL

TARGET setting. Larger DIFF TANK and DIFF

settings will slow response to demand, but may save

energy.

If unit short cycles, enter Advanced

Programming mode (Section 6.4) and increase

BOILER MAX setting to the BOIL TARGET setting

or higher. Set BOILER MIN to 120°F / 49°C, and

STGMODE to PID. See Section 6.4.12 Advanced

Programming Mode to enter Advanced Programming

mode, or contact the factory for assistance.

EXAMPLE 2

Hydronic Primary/Secondary (Mode 2)

Figure 26. Temperature Control Symbol Description.

1 2 ... 34 35 36 37 38 39 40 41 42 43 44 ... 63 64

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Bradford White BWCH Operations Instructions Page 39

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