Installation / Operation Instruction Manual

Addendum H2381401- to Brute LX 1295A
Document 1372
H2381401-
The 14 updated pages of document 1295A. The Brute LX (Series 1, wall only) Installation and Operating Manual.
Page 37
Brute LX
9.2 Hydronic Heating with Outdoor Reset
Outdoor reset varies the control setpoint based on
the outdoor temperature. The reset function works as
shown in Figure 24.
When the outdoor air temperature is a low as P61 “low
outdoor temperature setpoint” (10°F in this example),
the control setpoint is adjusted upward to P62 “high
boiler temperature” (180°F in this example). When
the outdoor air temperature rises to P63 "high outdoor
temperature setpoint” (68°F in this example), the
control point setting is lowered to P64 “low boiler
temperature setpoint” (120°F in this example).
P65 " Warm Weather Shutdown" is shown in Figure 24
as being set at approximately 72°F.
9.3 Hydronic Heating Using External
Modulation Control (BMS)
The Brute LX can accept a 0-10 VDC input
to integrate with a building management system
or external modulating control. Utilizing Installer
Parameters P31 “BMS Voltage at minimum” and P32
”BMS voltage at maximum” the installer can set the
minimum and maximum input voltages. By default
this input is enabled but can be disabled using Installer
Parameter P30 “0-10v Input Enable / Disable”.
The Brute LX can use an external 0-10VDC signal to
control its fan speed (modulation rate), or to control its
outlet setpoint. The 0-10V signal may also be used to
create a heat demand eliminating the need to supply a
separate “TT call”.
9.3.a External Signal to Control Modulation.
Installer Parameter P25 “0-10V to Power (fan speed)”
– This is the default 0-10VDC conguration in which
the external signal directly corresponds to fan speed
or ‘boiler power’ In this mode, the call is initiated by
the 0-10v input based on Installer Parameters P33 “On
threshold voltage” and P34 “Off hysteresis voltage”. The
modulation power can also be scaled with P35 “BMS rate
at minimum voltage” and P36 “BMS rate at maximum
voltage”.
9.3.b External Signal to Control Setpoint.
Installer Parameter P25 “0-10v BMS modulation control”
must be disabled – In this mode the 0-10VDC input
directly controls the boiler's outlet temperature. Set the
parameters using the Installer Parameters P37 “ BMS
Temperature setpoint at minimum voltage” and P38
“BMS temperature setpoint at maximum voltage”
9.3.c External Signal Initiates Heat Demand
In this mode P26 “0-10V BMS Thermostat Demand
Required” must be disabled to eliminate the need for
a separate “TT Call”. This allows a heat demand to be
created every time the 0-10V signal exceeds P33 “BMS
On Volts”. The heat demand will remain until the 0-10V
signal drops below P33 “BMS On Volts” – P34 “BMS
Demand Off Differential Voltage”
9.4 Warm Weather Shutdown
Warm weather shutdown overrides a central heat
call when the outdoor air temperature is greater than
the warm weather shutdown setpoint. Warm weather
shutdown is always active when there is an outdoor
sensor attached to the control. The warm weather
shutdown setpoint can be adjusted in Installer mode,
using P65 “CH outdoor Air Shutdown Temperature” and
P66 “CH Outdoor Air Shutdown Differential”.
9.5 Domestic Hot Water Demand
9.5.a Combi Boiler DHW
For Combi units (BMLXC), DHW demand is triggered
by a ow sensor located near the DHW cold water inlet.
When water begins to ow (open faucet, shower, etc.),
the boiler will re, based on the water temperature
requirements. It may cycle on and off under very low
ow rates. Minimum ow is 0.5 gpm.
9.5.b Boiler only DHW aquastat demand
For Boiler only units (BMLXH), an indirect water heater
can be piped-in. An aquastat in the indirect water heater
connected to terminals 7 and 8 will signal demand for
DHW. In this demand mode the boiler will modulate on
the outlet water temperature sensor and use P51 “DHW
setpoint (S1 – Tank) as the setpoint.
9.5.c Boiler only DHW sensor demand
An optional DHW sensor (Bradford White PN
E2337501) can also be installed in an indirect water
Figure 24. Outdoor Reset Setpoint Temperatures.
Operating condition
(warm weather shutdown)
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