| Gas Heater Cleaning, Heat
Exchanger |
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Note that the purpose of this section is to
show you how to clean a gas heater that has a dirty or clogged heat exchanger.
This condition will normally be found on gas heaters that are more than 5-8
years old, however, depending on environmental conditions, can happen more
often.
Safety
Warnings!
| Remove Power from the spa/hot tub, AND the gas heater
(if powered from outside sources), BEFORE performing this procedure.
Failure to comply with this requirement, can lead to electrical shock and/or
electrocution! Turn OFF the GAS SUPPLY to the heater! Failure to comply with
this safety requirement may create a fire or EXPLOSION
HAZARD!
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Disclaimer
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The instructions here are intended
for general reference only. Many gas heaters are different from the one
depicted here, and may require more or less mechanical effort or knowledge in
order to achieve the desired results. |
READ FIRST BEFORE YOU
CONTINUE
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This is
a typical gas heater installation. While it does work, and has worked well for
many years, you can see that there is a safety problem with running the gas
line over the top of the heater. In order to maintain continuity, we will only
address the heat exchanger cleaning. Usually, the only tools required for this
job are a 1/4" and/or 5/16" nut driver.
This particular heat exchanger is clogged
very heavily, and does not allow for the proper flow of heat from the burners
to escape to the ventilator.
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 This is typical
heat damage due to a clogged heat exchanger.
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Determine which tool is required
to remove the top of the heater, and remove the screws that attach the top vent
to the main heater housing. Typically, there will be 8 screws. Be careful with
the sheet metal, it can cut you! |
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With all of the screws removed, carefully
lift up the ventilation unit it separates from the base. On certain heaters, it
may require a bit of force to get it off. If all else fails, recheck to see if
there are any screws that you may have missed. |
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With the
top off of the heater, you'll probably encounter something that looks like
this... There may or may not be screws attaching it to the top of the heat
exchanger. If so, then remove them to gain access to the entire heat
exchanger. |
| This is what you should see, the top of
the heat exchanger with the heat containment shields on top. There is usually a
wire that holds them in place, (used primarily for shipping reasons), that you
can probably just pull off with your fingers or cut with a pair of wire
cutters. Once the wire is removed, take note of where the shields are located
(for replacement), remove them and put them aside. |
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Look very closely at the
grids (fins) of the heat exchanger, and you'll probably see quite a bit of
built up "gunk" inside them. This is what causes the heater to
over-heat... it literally chokes itself. |
Using a directed pressure stream of water,
clean the exchanger thoroughly. This normally will only require about 30
seconds to do. DO NOT USE A PRESSURE WASHER! You could permanently damage the
heat exchanger! Also,
keep the stream directed straight DOWN... so to prevent the saturation of the
insulation inside the heater. This is quite critical, particularly in older
heaters that use conventional hard fire-brick.
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Reassembly
Reassembly is simply the reverse of
disassembly. For safety reasons, you should let the heater
"dry out" for about 24 hours before putting it back into operation.
Because of the possibility of water entering the burners, it can create a fire
hazard because the gas will be blocked from its normal path. It is recommended
that you use some type of air blower to blow out all water and other foreign
matter from the burner area before igniting the heater and pilot light (if
equipped) again.
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