Harman PB105 - Combustion Blower Maintenance; Tube Heat Exchangers

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3-90-07205R26_10/14
Combustion Blower/Heat Exchanger Maintenance
The boiler MUST be OFF and COOL before you should
attempttocleanthecombustionblower.
The wire to the combustion blower doesn’t need to be
disconnectedduringthecleaningprocess.
Loosenthethree(3)thumbscrewsabout4turnseach.See
Fig.23.Holdthemotorheadwithonehandandtheblower
platehandlewiththeotherhand.Pulloutwardontheplate
handleuntilthecompleteunitcomesloose.Nowrotatethe
platecounter-clockwiseabout1/8turn.Thiswillallowthe
completeassemblytoberemovedfromtheblowerchamber.
Cleanthe blowerfan bladesandthe blowerplate sealing
overlap.SeeFig.24.
NOTE: Be careful not to bend the fan blades, this will
throw the fan blade out of balance or it may rub the inner
chamber, which may affect the performance of the boiler.
Any horizontal and vertical ue pipe directly above the
unit should be cleaned at this time
NOTE: The horizontal ue pipe directly above the boiler
is the rst place y ash will settle, due to the slowing
of ue gas velocity through horizontal pipe. Cleaning
of horizontal venting pipes is very important to the
efciency of this boiler.
Clean the ue outlet throat as well as the inner chamber
oftheuetunnel(thisistheholethatgoesupintotheue
pipe).SeeFig.24.
NOTE: The exhaust probe sensing tip extends into this
same area. CARE MUST BE TAKEN NOT TO DAMAGE
THE ESP DURING CLEANING. Bending of the ESP will
make it difcult to remove if it should become necessary.
See Fig. 23.
Cleantheboilerblowerplate,sealingoverlap.SeeFig24.
Makesuretherearenoyashbuildupsthatmayblockthe
easy ow of ue gasses into the combustion blower inlet
hole.(Aashlightmaybenecessary.)
Cleaning the Tube Heat Exchangers:
Three external cleaning rods allow scraping of the heat
exchange tubes with a simple in-and-out motion. See
previouspage.
Thiscleaningshouldbedoneatleastonceaweek,however
itcanbedonemoreoftenasdesired.Thecleanertheheat
exchangersare,themoreefcienttheboilerwillbe.Itisbest
toperformduringalowreperiodorwhenthereisout.
Duringhighreperiods,thecleaningrodsmaystickdueto
heatrelatedexpansion.
Combustion Blower Cleaning
Removethecombustionblowerheatshield.Therearetwo
latchesthatholdtheshieldinplace(SeeFig.22).Flipthe
latchesupandpulltheshieldawayfromtheboiler.Itcannot
befullyremoved,itcanonlybemoveddownoverthewire
untilithangsonthejunctionbox.
Fig. 23
Latch
Heat Shield
Fig. 22
Fig. 24
Sealing
Overlap
5” Double
Bladed Fan
CAUTION
!
Inspect ue pipes, ue pipe joints and ue pipe seals
regularly to ensure that smoke and ue gases are not
entering the home.
ESP
Combustion
Blower Motor
Thumb Screws (3) Total