Raypak 408 Installation And Operation Manual page 31

8.5.11. Pilot Removal And Cleaning
1. Disconnect pilot tubing and wires from gas valve.
2. Remove pilot assembly from burner tray.
3. Remove pilot from bracket.
4. Remove pilot orifice and air opening, and clean with
wire or small brush.
CAUTION! Do not enlarge hole in pilot orifice.
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5. Reverse above procedure to reinstall.
Extension
Pieces (2)
Figure 50. Tube Cleaning Kit
8.5.12. Heat Exchanger Removal
1. Shut water, gas and electricity off, close valves and
relieve pressure, then remove relief valve. Remove
side inspection panels.
2. Remove top jacket holding screws.
3. Remove rear top panel.
4. Remove screws mounting the rain shield to the rear
panel. Also remove the screws that mount the rain
shield to the sway brace. Remove rain shield.
5. Remove the four (4) screws holding down the flue
collector. Remove the flue collector.
6. Disconnect flange nuts on Inlet/Outlet header,
loosen union(s) at gas pipe and slide heater away
from piping.
7. Lift heat exchanger straight up using caution not to
damage refractory.
8. Reverse above procedure to reinstall. Make sure the
insulation strips are properly replaced on top of the
refractory retainer.
8.5.13. Tube Cleaning Procedure
Establish a regular inspection schedule, the frequency
depending on the local water conditions and the severity
of service. Do not let the tubes clog up solidly. Clean out
deposits over 1/16" in thickness.
The heater may be cleaned from the return header side,
without breaking pipe connections. It is preferable,
however, to remove both headers for better visibility
through the tubes and to be sure the ground-up lime dust
does not get into the system. Note that you do not remove
the top panel or the heater exchanger, generally.
Auger Wire Brush
with Carbide Tip
After reaming, mount the wire brush in place of the auger
and clean out debris remaining in the tubes. Another
method is to remove the heat exchanger, ream tubes and
immerse heat exchanger in non-inhibited de-scale solvent
for severe scale build-up.
8.5.14. Desooting Procedure
WARNING: Soot Is Combustible. Exercise Extreme
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Care.
Soot will clog areas between fins and cause eventual
tube failure. Any sign of soot at the base of the burners or
around the outer jacket indicates a need for cleaning.
1. Remove top and flue collector from cabinet.
2. Remove "V" baffles from heat exchanger.
3. Remove burner tray.
4. Remove heat exchanger from the heater and wash
with a garden hose, making sure soot is removed
from spaces between fins.
5. Reverse above procedure to reinstall.
NOTE: In extreme cases it may be necessary to do steam
cleaning at the local car wash. DO NOT WIRE BRUSH.
8.5.15. Combustion Chamber Removal
To remove combustion chamber, you must first have
removed the heat exchanger.
Figure 51. Atmospheric Heaters
8.5.16. Immersion Well Replacement
1. Shut off water to heater and drain heat exchanger.
2. Remove access panel on water connection side.
3. Remove old immersion well with bushing and sleeve.
4. Install replacement well in header.
Figure 52. Well Assembly
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