Laars Pennant PNCH Installation And Operation Instructions Manual - page 40
LAARS Heating Systems
Page 40
EXAMPLE 2
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
ADJUST
ADJUST
ADJUST
ADJUST mode (Figure 25). Press Item
Item
Item
Item
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
BOIL TARGET
BOIL TARGET
BOIL TARGET
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.