Modine Manufacturing PTP Manual page 3

BMS BOARD FUNCTION
Space Temperature Feedback Method
ON – 10K Ohm NTC Type III Sensor
OFF – Mechanical/Programmable Thermostat
(default)
HEATING THERMOSTAT CONTROL
If thermostat signals are provided as digital inputs (dip switch SW4.7
must be set "off" for T-stat operation), the unit will call for heat when
the thermostat passes 24VAC to W1. The BMS Board comes
factory set for this operation. When a W1 signal is received, the
Gas Valve Stage output H1 will energize. When a W2 signal is
received, the Gas Valve Stage 2 output H2 will be energized. When
the W2 call is removed, the Gas Valve Stage 2 output H2 will be
de-energized. When the W1 call is removed, the Gas Valve Stage 1
H1 output will be de-energized.
SENSOR CONTROL
If a return air signal is provided (wired into analog input T1,
dip switch SW4.7 must be set "on" for sensor operation), there
will be a call for heat whenever the sensor reads 1°F lower
(setpoint_band default value, 1°C) than the heat_setpt_BMS
value (default 70°F, 21°C). Once this temperature has been
reached, Gas Valve Stage 1 output H1 will be energized. If
the temperature drops an additional 2°F (1.1°C), the Gas
Valve Stage 2 output H2 will be energized. H2 will de-energize
when the temperature raises to the temperature that originally
turned on stage 1 heating. When the temperature returns
to the setpoint (heat_setpt_BMS) value, output H1 will be
de-energized.
ENERGY SAVER FUNCTION
If the Intake sensor T2 is reading 85°F (saver_setpt_BMS
default value, 29°C) or above when the sensor or W1 signal
calls for heat, the board shall only energize the Blower output G,
until the sensor or W1 call is removed, or until the intake sensor
drops 3°F lower (saver_band default value, 1.5°C) than the
saver_setpt_BMS value.
BMS CONTROL CHANGING THE UNIT CONTROL
OVER NETWORK
If the BMS is sending a Superv_OnOff parameter of 'off' to the unit,
the equipment will not energize an output regardless of sensor/stat
inputs.
If the unit is operating with sensor control, the value of the space
setpoint, band, and energy saver setpoint can be adjusted over BMS
network. If unit is not on BMS network and running in sensor control,
the unit will operate at default values per Table 6.1 & 7.1. If the unit
is running in thermostat control, the setpoints and bands will be
governed by the thermostat.
The unit may be set over BMS to run in summer mode by changing
the summer_winter digital variable address value to 1. See the 'FAN
ONLY' section for more details about unit control in this mode. The
unit ships with the default value for this address at '0', which puts the
unit in winter mode for normal heating function.
The unit temperature values can be changed to report temperatures
in °C instead of °F by changing the C_F_Scale object value to 1 (°C)
instead of 0 (°F, factory default).
All modes and setpoint/band values can be restored to their factory
setting by setting the RestoreDefault object value to 1 (the value will
self-reset to 0).
MONITORING UNIT STATUS
The unit will report the status of various component and space
conditions over BMS network as it operates. See the description
of the object list in Tables 6.1 & 7.1 for more information about the
points.
BMS ALARMS
If the board reads an analog input temperature on any channel
below -150°F (-101°C) or above 200CF (93°C), the unit will
display an al_BrokenPrbTemp alarm, and the board should
not energize any output as long as the condition persists. On
analog input 1, this only applies if unit is operating on sensor
control (dip switch set to sensor control). If a unit is operating
on stat control, the al_BrokenPrbTemp alarm will only be used
regarding analog input 2 (intake air).
al_highlimit_FRO_alarm will be indicated if there is a call
for heat and no signal through the high limit(s) or flame
rollout switch(es) to the Lim input terminal. Unit would trigger
immediate alarm. Alarm status will clear when signal closes.
al_pressure_switch will be indicated when there is a call for
heat, but the pressure switch is not pulled in and no signal to
P input terminal. There is a 90 second delay before pressure
switch status is observed, and requires a continuous 60 second
loss of pressure switch signal to generate the alarm. Chattering
of a pressure switch will not trigger alarm. When there is no call
for heat the pressure switch should be open. If it isn't, the alarm
will be indicated if the status is closed for over 90 continuous
seconds. The al_pressure_switch alarm will be ignored if other
alarms are already present.
al_valve_ignition_alarm will be indicated when there is a
continuous call for heat for at least 300 seconds, there are no
other unit alarms, and the gas valve signal is not present on V
input terminal. This alarm will be cleared when valve status is
closed for 15 continuous seconds.
All alarms will reset on power cycle.
FAN-ONLY
The unit can receive a fan-only call in two ways. A unit can be set by
BMS to have the summer_winter variable set to 1 (summer mode)
for the unit to energize a fan-only call. If a return air signal T1 is
provided (dip switch SW4.7 must be set "on" for sensor operation),
the unit will call for fan-only when the sensor reads 1° (value of
setpoint_band) higher than the fan_setpt_BMS value (default 75°F,
24°C). Once this value has been reached, the Blower output G
will be energized. When the return air temperature returns to the
setpoint, the Blower output G should be de-energized.
Alternately, if thermostat signals are provided as digital inputs, the
unit will call for fan operation on a G signal. When a G signal is
received, the Blower output will be energized. When the G call is
removed, the Blower output will be de-energized.
Wiring Connections
Field connections must follow the wiring diagram supplied with the
unit. Terminal boards may be factory-supplied on your unit heater for
external stat connections (See Figure 4.1 It may be required to route
some wiring directly to the BMS Board, which may be internal to
the control cabinet. In these cases, you may puncture the provided
rubber grommet to route cabling into the control area (See Figure
4.2).
6.520.3
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