LAARS Mighty Max HH (Sizes 320M - 400M) - Installation, Operation and Maintenance Instructions - Manual (Page 24)

Page 24
LAARS Heating Systems
7. Be sure all combustion air and ventilation
openings are not blocked.
8. After installation and first startup, check the heat
exchanger for black carbon soot buildup after the
following periods of operation: 24 hours, 7 days,
30 days, 90 days, and once every 6 months
thereafter.
4.2 Heat Exchanger
Black carbon soot buildup on the external
surfaces of the heat exchanger is caused by one or
more of the following: incomplete combustion,
combustion air problems, venting problems and heater
short cycling. As soon as any buildup is seen, correct
the cause of the buildup. Scale can build up on the
inner surface of the heat exchanger tubes and
restrict the water flow. Inspect the heat exchanger in
accordance with Section 4.2.1.
If the heat exchanger needs cleaning, see
Section 4.2.2.
4.2.1 Inspection of the Heat Exchanger
WARNING
Improper installation or maintenance can cause
nausea or asphyxiation from carbon monoxide in
flue gases which could result in severe injury,
property damage, or death.
AVERTISSEMENT
Une installation ou un entretien inadéquat peut
causer des nausées ou l’asphyxie provenant du
monoxyde de carbone présent dans les gaz de
combustion et provoquer des dégâts matériels, des
blessures graves, voire la mort.
4.2.1a External Heat Exchanger
Inspection
1. Disconnect electrical supply to the heater.
2. Turn off the gas supply by closing the manual
gas valve on the heater.
3. On indoor models, remove the vent pipe, top
jacket section, flue collector.
4. On outdoor models, remove outdoor vent
terminal, top jacket section, flue collector.
5. After removing the flue collector, inspect the
finned copper tubing using a flashlight.
6. If there is a buildup of black carbon soot or other
debris on the heat exchanger tubes which may
restrict flue gas passage, refer to Section 4.2.2a.
7. If there is no buildup of black carbon soot or other
debris which may restrict flue gas passage through
the heat exchanger, reassemble the heater.
4.2.1b Internal Heat Exchanger Inspection
1. Remove the inlet/outlet header of the heat
exchanger.
2. Remove the return cover of the heat exchanger.
3. Inspect the internal surface of the copper tubes
for signs of scale buildup and erosion.
4. If build-up exists, clean per 4.2.2b.
4.2.2 Cleaning the Heat Exchanger
4.2.2a Cleaning the Heat Exchanger -
External
NOTE: The heat exchangers are heavy and may
require two people to remove to avoid personal injury.
WARNING
Black carbon soot buildup on a dirty heat exchanger
can be ignited by a random spark or flame, which
can lead to property damage, or death. To prevent
this from happening, dampen the soot deposits with
a wet brush or fine water spray before servicing the
heat exchanger.
AVERTISSEMENT
L’accumulation de suie noire sur un échangeur de
chaleur sale peut être enflammée par une étincelle
ou une flamme. Pour éviter ce genre d’accident,
humectez les dépôts de suie avec une brosse
mouillée ou une aspersion légère d’eau avant de
travailler sur l’échangeur de chaleur.
1. Disconnect the 120 Vac electrical supply to the
heater.
2. Turn off the gas supply by closing the manual
gas valve on the heater.
3. Disconnect and remove the wires and conduit
from the low water cutoff.
4. Remove the top jacket section, venting and the
flue collector as mentioned in Section 4.2.1
“Inspection of the Heat Exchanger”.
5. Isolate the heat exchanger from water supply.
6. Drain the heat exchanger.
7. Disconnect the flange and adapter tee from the
heat exchanger inlet and outlet.
8. Remove temperature sensing probes from the
inlet/outlet header.
9. Remove the heat exchanger from the heater.
10. Remove the heat baffles from the heat
exchanger.
11. Clean the heat exchanger: A light accumulation
of soot or corrosion on the outside of the heat
exchanger can be easily removed after the heat
baffles are removed. Use a wire brush to remove
loose soot and scale from the heat exchanger. Do
not use water or compressed air for cleaning.
NOTE: While the heat exchanger is out of the heater,
inspect the firewall refractory insulation blocks for
cracks, wear and breakage. Replace if necessary.
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