LAARS Pennant PNCP - Install and Operating Manual - Manual (Page 22)

LAARS Heating Systems Page 22
SECTION 8.
Trouble Shooting
8.1 Resolving Lockouts
There are many causes of lockouts. The three
most common causes are: (1) inadequate gas supply,
(2) poor combustion, (3) ignitor failure.
1. Inadequate gas supply: Before proceeding, ensure
that the gas supply has not been shutoff or the LP
tank (LP boilers) is not empty. Then, restart the
boiler and observe the operational cycle. After
a 15-second fan pre-purge, the ignitor will heat
up for 20 seconds, and then the unit will light.
If it does not, check the gas supply pressure to
the appliance, after resetting the appliance and
attempting another start-up. The gas pressure to
the appliance must be above 5" W.C. (1.2kPa)
throughout the entire start-up cycle. If it is not,
correct the supply problem (check gas valves or
supply piping). If the supply pressure is adequate,
consult the factory for assistance.
2. Poor Combustion: Poor combustion should be
suspected if there is a strong flue gas odor. The
odor may result from an improper gas/air ratio
(high or low O
2
or CO
2
). Pennant appliances
operate best with 45% excess air (8% CO
2
on
natural gas, 9.2% CO
2
on LP). Check the CO
2
of
the appliance and adjust if necessary.
3. Ignitor failure: If the boiler goes through a
normal start cycle but combustion does not
occur, and the gas pressure is at least 5" w.c.,
ignitor failure may be the cause. Check the
ignitor by unplugging it, allowing it to cool to
room temperature, and measuring the ignitor
resistance. It should be 50-80 ohms. If the
resistance is not 50-80 ohms, replace the ignitor.
If the resistance is correct, reset the boiler and
check for 120 VAC at the ignitor plug during
the start cycle. If there is no voltage, replace the
faulty ignitor wire harness or the ignition control.
8.2 Delayed Ignition - Possible Causes
A defective burner can cause a delayed ignition.
If the gas supply pressure is proper and the gas
valves are functioning properly, then burners should
be inspected. There should be no distortion or
perforations in the burners outside of the active burner
port area. Replace if indicated.
8.3 Short Cycling
Because of the large mass of pool systems, short
cycling should not exist. If it does, it will be caused
by insufficient flow in the pool loop. Check that there
is no blockage in the pool loop such as a plugged or
partially plugged pool filter.
side panels. Remove the front lower panels
sealing the combustion area. To remove the
gas train, disconnect the unions located above
the intermediate pan and the field installed
union located outside the cabinet, and pull up,
bringing the union end connectors through the
grommets in the intermediate pan. To remove
the intermediate pan, remove the slide out control
assembly and blower(s) to reveal the screws.
Remove the screws holding the intermediate pan,
and lift up to remove it. The heat exchanger has
integral metal sections attached, which connect
to the frame of the boiler. Locate and remove
the screws along the front, rear and bottom of
the integral metal sections, and remove the heat
exchanger and metal sections by lifting up. On
the larger appliances, a center heat exchanger
support must be unbolted before it can be
removed.
7. Remove the heat exchanger from the unit.
NOTE: The heat exchangers are heavy and will
require two people to remove to avoid personal injury.
8. Clean the heat exchanger: A light accumulation
of soot or corrosion on the outside of the heat
exchanger can be easily removed. Use a wire
brush to remove loose soot and scale from the
heat exchanger. Do not use water or compressed
air for cleaning.
9. NOTE: While the heat exchanger is out of the
unit, inspect the firewall refractory insulation.
Replace if necessary.
10. Inspect the inside of the copper tubes for scale
buildup. Scale can build up on the inner surface
of the heat exchanger tubes, which can restrict
water flow. If the tubes show signs of scaling,
clean the internal surface. Laars offers a tube
cleaning kit part number R0010000.
11. Reassemble in the reverse order, and check
appliance operation after start-up.
NOTE: The Warranty does not cover damage
caused by lack of required maintenance, lack of
water flow, or improper operating practices.