LAARS Pennant PNCV (Sizes 500-2000) - Install and Operating Manual - Manual (Page 49)

Pennant (500-2000) Page 49
and boilers ordered with low temperature controls. To
replace the switch, shut off the 120-volt power to the
appliance. Remove the cover from the switch to access
the mounting screws. Remove the screws, and pull the
switch off the control panel. Remove the capilliary
and bulb from the thermal well located in the header.
Replace in reverse order.
7.2.6 Temperature Control
The temperature control is a Laars LHSC. To
replace the control, shut off the 120-volt power to
the appliance. Remove the cover from the control
panel, and remove the mounting screws to remove the
controller. Replace in reverse order.
7.2.7 Ignition Controls
The ignition controls ensure the proved
interrupted-type ignition system. They control the
hot surface ignitors and prove that the flame signal
is appropriate for powering the gas valves. It also
controls the blower’s pre-purge and post-purge.
Pennant sizes 500 and 750 have one ignition control.
Sizes 1000 to 2000 have two ignition controls. On
sizes 1000, one ignition control controls stages 1 and
2, and the second ignition control controls stage 3. On
sizes 1250–2000, one ignition control is for stages 1
and 2, and the other is for stages 3 and 4.
To replace a control, shut off the 120-volt power
to the appliance. Remove the cover from the control
panel. Remove the electrical connectors from the
ignition control. Take out the controller’s mounting
screws, and pull the controller out. Replace in reverse
order.
7.2.8 Ignitors
The ignitors used are 120v “Hot Surface” type.
They are energized whenever there is a call for heat
and switched off when ignition is established and the
flame has been sensed. Pennant sizes 500 and 750 have
one ignitor. Sizes 1000 to 2000 have two ignitors. To
replace the ignitor, shut off the 120-volt power to the
appliance, remove the ignitor access panel, disconnect
the Molex connector, remove the two mounting screws
on the ignitor flange, and pull the ignitor out. Install in
reverse order, always using a new ignitor gasket with
the replacement ignitor.
Caution
Ignitor gets hot.
7.2.9 Ignition Sensors
The ignition sensors ensure that the main flame
is ignited, so that raw gas is not allowed to fill the
combustion chamber. Pennant sizes 500 and 750 have
one sensor. Sizes 1000 to 2000 have two sensors (one
for each ignition control). The ignitors are the ignition
sensors on Pennant appliances. There are no separate
ignition sensors.
7.2.10 Transformer
The Pennant’s transformer is not capable of
supplying control voltage for external devices such
as zone valves, which must have their own separate
power supply. Should a transformer need replacing,
shut off the 120-volt power. Unplug the transformer
wires, remove the mounting screws and remove the
transformer. Replace transformer in the reverse order.
7.2.11 Blowers
The combustion air blowers bring the combustion
air for the Pennant from the upper chamber to the
lower chamber. Mixing of the gas and air occurs in
the burners. Sizes 500, 750 and 1000 each have one
blower, and sizes 1250 to 2000 each have two blowers
(one blower for stages 1 and 2, and one for stages 3
and 4). If a blower change is required, turn off the
120-volt power and gas supply to the unit. Remove
the front panel. Disconnect the blower's wire harness.
Remove the screws at the blower flange, and pull the
blower out. Replace blower in reverse order, ensuring
that all joints are made correctly. After replacement,
ensure that the unit operates properly, by following the
set-up procedure in this manual.
7.2.12 Flow Switch
The Pennant uses a paddle-type flow switch to
ensure that the unit has water flow before ignition is
allowed.
7.2.13 Heat Exchanger Coil
WARNING
Black carbon soot buildup on a dirty heat exchanger
can be ignited by a random spark or flame, thereby
creating a risk of fire or explosion.. To prevent this
from happening, dampen the soot deposits with a
wet brush or fine water spray before servicing the
heat exchanger.
The Pennant has a pre-mixed burner system.
These systems provide the burners with sufficient air
for complete combustion, and black carbon sooting
is seldom experienced. If sooting is suspected, view
ports for inspection of the heat exchanger are provided
on both sides of the boiler. They are located below the
headers, and are accessed by opening the small round
cover that is attached by one screw. In the unlikely
event that there is a buildup of black carbon soot
or other debris on the heat exchanger, clean per the
following:
1. Disconnect the electrical supply to the unit.
2. Turn off the gas supply by closing the manual gas
valve on the heater.
3. Disconnect and remove the wires, conduit and
sensors from all components that are attached to
the inlet/outlet header.
4. Isolate the heat exchanger from the water supply.
5. Disconnect header flanges from inlet and outlet.