TUBE REPLACEMENT PROCEDURE
On Raypak units, tube replacement may be ef- fected without rolling, as a temporary means of repair, providing there are two or more tubes rolled in to act as stays on the left or right sides. The "O" rings should provide a seal up to 125 PSI working pressure. Use 3/ 8" heavy duty reversible drill motor or larger to power the tube roller. If a reversible drill is not available, after rolling the tube in, remove the drill motor and wrench out the roller. A tube roller is available from the factory.
Shut gas and power off to the unit, close the system off and drain the heater. Remove the draft diverter. Remove the access panel and jacket top. Lift the flue collector off. Remove "V" baffles over tube(s) to be replaced. If no pipe unions have been provided, use the header as a union, remove the flange nuts off the inlet- outlet header, break gas connection and slide heater away from piping to allow room to work. Pull wedge clips out of control wells and remove sensing bulbs. Lift heat exchanger straight up and out.
Inspect header gaskets at this time. Unless sev- ered, they are reusable. The tube may be cut out with a hacksaw or hammer and chiseled adjacent to both tube sheets, leaving studs in the tube sheets. Then proceed to collapse studs in the tube sheets with a chisel or screwdriver. Use caution not to cut into the tube sheet. Replacement tubes will have the fins stripped off longer on one end. The long end is inserted into the opening of the tube sheet first; then the short end is fitted through the opposite tube sheet. If the tube ends become dented or bent, straighten at least (4) inches back from the tube end by means of a tapered punch.
Insert tube roller into tube opening up to stop against tube, then push center rod in until roller is tight. Be careful to keep replacement tube squared up 1/8" outside each tube sheet. A loose tube will sometimes pull toward the roller. Attach drill motor to tube roller, holding it straight and level. Proceed to expand tube until the tool begins to grab. At this point, 1/2" to 1" should be exposed on the tool shank. Reverse drill motor or wrench out by hand. Care should be exercised to avoid applying excessive torque during rolling op- eration and to avoid thinning out any part of the tube wall excessively over .015". Use same procedure at the opposite end of the tube.
Apply line pressure test, and
DESOOTING PROCEDURE
CAUTION: SOOT IS COMBUSTIBLE. EXERCISE EXTREME CARE.
Soot can clog areas between fins and cause even- tual 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 drawer. (See burner tray removal).
4.Take garden hose and wash heat exchanger, making sure soot is removed from between fins. (Avoid excessive water against refractory).
5.
NOTE: In extreme cases it may be necessary to re- move the heat exchanger completely for cleaning. The simplest method is steam cleaning at the local car wash. DO NOT WIREBRUSH.
COMBUSTION CHAMBER REMOVAL
To remove combustion chamber, you must first have removed the heat exchanger. Unbolt metal com- bustion chamber retainer from top and remove com- bustion chamber panels individually.
REFRACTORY PANELS TOP VIEW
Fig. # 8155.0
RAYPAK TUBE CLEANING KIT
Extension Pieces (5) | Auger with Carbide Tip | Wire Brush |
Fig. # 8154.0
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