Install Instructions
Page 52
LAARS Heating Systems
Heat Exchanger Coils
Black carbon soot buildup on the heat exchanger is caused
by one or more of the following; incomplete combustion,
combustion air problems, venting problems, or heater short
cycling. Soot buildup or other debris on the heat exchanger
may restrict the ue passages.
If black carbon soot buildup on the heat exchanger is
suspected, disconnect the electrical supply to the unit, and
turn o the gas supply by closing the manual gas valve on
the unit. Access the heat exchanger through the burner
door at the front of the boiler, and inspect the tubing using a
ashlight. If there is a buildup of black carbon soot or other
debris on the heat exchanger, clean using this procedure:
WARNING
Black carbon soot buildup on a dirty heat exchanger
can be ignited by a random spark or ame. To prevent
this from happening, dampen the soot deposits with a
wet brush or ne water spray before servicing the heat
exchanger.
1. Shut o the 120 Volt power supply to the boiler
2. Turn o all manual gas valves connecting the boiler to
the main gas supply line.
3. Remove the four bolts connecting the blower ange
to the burner door arm.
4. Remove the nuts located on the outside diameter of
the burner door to the heat exchanger.
5. Remove the burner door and burner assembly from
the heat exchanger.
6. Disconnect the condensate drain line.
7. Attach a longer hose to the drain and run it to a
bucket.
8. Clean the heat exchanger by brushing away any light
accumulations of soot and debris. Use a brush with
soft bristles (non metallic) to avoid damaging the
surfaces of the heat exchanger tubes.
9. Once the tubes have been brushed clean, rinse the
tubes and combustion chamber with a small amount
of water to rinse all of the debris out of the bottom of
the ue collector and into the longer condensate trap
line. This will be diverted into the separate container.
NOTE: The Warranty does not cover damage
caused by lack of required maintenance, lack of
water ow, or improper operating practices.
WARNING
Failure to rinse the debris from the heat exchanger and
temporary drain line may lead to clogged condensate
lines, traps and neutralizers. Condensate pumps (if used)
may also be damaged by the debris left behind, possibly
causing property damage.
10. Install all components removed in the reverse order to
place the unit back in operation. Be sure all gaskets
are in place as the components are installed. Replace
any damaged gaskets. Do not reuse damaged
gaskets.
11. Place the unit into operation according to the
instructions in Section 10. Check all gas connections
for leaks. Conrm that all fasteners are tight.
Optional Pressure Gas Switches
The high and low pressure gas switches are 24V manual
reset switches that act to cut power to the gas valves if the
gas pressure is too low or too high for proper operation.
If your boiler is equipped with the Optional pressure gas
switches, then the Low Pressure Switch will need to be
reset.
The pressure gas switches used are integrally vent limited,
and do not require venting to atmosphere. To remove a
switch, remove the screw on the plastic housing and pull
the clear cover o. Disconnect the two wires from the screw
terminals. Twist the switch o the pipe nipple. Reassemble
in reverse order. For natural gas, set the low pressure gas
switch to 3” w.c. For propane, set the low pressure gas
switch to 5” w.c. For natural and propane, set the high
pressure gas switch to 14”.
10.C Gas Conversion
These units can easily be converted from natural to propane
gas or from propane to natural gas in the eld. Some units
require the addition of a gas orice along with proper gas
valve adjustment. Other units require no additional parts
at all- only a proper gas valve adjustment. Please contact
your Manufacturers Rep for specic information regarding
the gas conversion of a particular unit or model. If a gas
conversion is performed, the unit must be identied with
the appropriate gas labels and a conversion sticker to allow
technicians performing maintenance in the future to properly
identify the type of gas being used in the unit.