LAARS Pennant PNCV (Sizes 500-2000) - Install and Operating Manual - Manual (Page 40)

LAARS Heating Systems Page 40
Hydronic Primary/Secondary (Mode 2)
Programming. Mode 2 is used in primary-secondary
piping hydronic systems without outdoor reset. Mode
5 adds outdoor reset.
Step 1: Install the additional sensor in the
primary loop (see Figure 4 ), and wired to the “SC2”
and “SUPS” terminals on the field wiring panel
(Figure 23).
Step 2: Remove the factory-installed jumper
between the “HtD” and “ComD” terminals on the
field wiring panel ( Figure 14 ), and connect a zone
valve or pump end switch or other contact closure
device (aquastat, etc.) to these terminals to provide an
indication of heat demand in the system.
Note: The boiler must have an indication of heat
demand to fire. If a zone valve or pump end switch is
not connected to the “HtD” and “ComD” terminals, the
jumper must be left in place. However, the boiler pump
(if equipped) and any pump connected to a contactor
wired to the PMP-PMP terminals on the field wiring
panel will run continuously and not cycle off according
to the setting for the Pump Delay. In addition, the LCD
screen will always show “dem” (demand) and will not
allow cycling of the display to verify all the sensor
settings.
Step 3: 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. See Section 6.3 Programming
the Temperature Control if more programming
instructions are needed.
Recommended settings for hydronic system with
180°F / 83°C primary loop temperature:
Item F° C°
MODE 2 2
BOIL TARGET 180 83
BOIL MASS 1 1
DIFF 20 10
DLY 5:00 5:00
F° F° °C
Step 4: See Section 6.4.11 Limit Controls. Set
both high limit controls at least 25°F / 14°C higher
than the BOIL TARGET to allow for temperature rise
across the heat exchanger.
6.3.4 Choosing the Mode for your
Application
This section describes various applications and
the recommended field wiring and Mode selections.
Mode 1: Boiler operates using its own inlet
and outlet sensors only, not relying
on a remote thermostat, aquastat,
or external sensor.
This setup is most commonly found in domestic
hot water applications with a continuous run pump.
This is not recommended for other applications.
The Pennant is shipped with a jumper between
the “Com D” and “Ht D” terminals, which must
remain in place to allow the unit to fire. The unit will
fire whenever the outlet temperature cools below the
target temperature.
Important Note: If the Pennant is pump-mounted at
the factory, or if a field-supplied pump contractor is
connected to the Pennant’s pump contactors
(Pmp Pmp), the user must program the controller’s
pump delay (DLY) setting to ON. When ON is selected,
pump operation is continuous. The unit’s inlet and
outlet sensors must be able to detect the temperature
in the storage tank in order to control it. Without the
tank water continuously running through the heater,
the heater will have no way of knowing what the
temperature in the tank is, and will not be able to
respond to a change in tank temperature. Short cycling
or lack of hot water may result if the pump does not
run continuously.
Mechanical aquastat in a domestic hot
water storage tank.
Remove the jumper from the “Com D” and
“HtD” terminals and connect the aquastat’s leads
to these terminals. This connection uses a standard,
non-powered mechanical aquastat. When the aquastat
calls for heat, the Pennant’s temperature control will
respond and start the boiler pump (if equipped) and
fire the boiler.
If the Pennant is not a pump mounted model,
a 24VAC pump contactor may be connected to the
“PMP” terminals to control a field installed pump.
(If desired, the pump can run continuously, with the
aquastat telling the heater when to fire.)
Program the temperature control to use Mode 1.
The AUTO/MAN switch must be in the AUTO position in
this mode.
Mode 3: Laars R2014800 sensor installed
in the domestic hot water storage
tank.
The Pennant ships with a jumper between the
“Com D” and “Ht D” terminals. Verify this jumper is
in place, and connect the sensor leads to the “S C2”
and “SUP S” terminals. When the sensor detects a
temperature below the target temperature, the control
will respond and start the heater pump (if equipped)
and fire the heater.
If the heater is not a pump mounted model, a
24VAC pump contactor may be connected to the
“PMP” terminals to control a field installed pump. (If
desired, the pump can run continuously).
Program the temperature control to use Mode 3.
The AUTO/MAN switch must be in the AUTO position in
this mode.