Assessments - 3, GPA: 3.7
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3. Turn vertical gas pipe from manifold slightly and unscrew gas valve. 4. Reverse above procedure to re-install. MAIN BURNER AND ORIFICE REMOVAL 1. Remove burner drawer. See burner drawer removal procedure. 2. Remove screws and burner hold down bracket. NOTE: If the heat exchanger is sooted badly, the burner hold down bracket and spacer can become distorted from direct flame impingement and this usually necessitates replacement of these parts. 3. Lift burners from slotted spacers and slide from orifices. Clean with a wire brush. 4. Orifices usually do not need to be replaced. To clean, run either copper wire or wood toothpick through orifice. Do not enlarge hole. To remove orifice, use a socket wrench and remove from manifold. DO NOT overtighten when reinstalling. Burner Hold Down Bracket BurnersFig. # 8057.0 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 (Honeywell MV unit only), and clean with wire or small brush. CAUTION! Do not enlarge hole in pilot orifice. 5. Reverse above procedure to reinstall. HONEYWELL PILOT ROBERTSHAW PILOT Air Opening Pilot Orifice Orifice Pilot Fig. # 8045.1 Fig. # 8102.0 24 HEAT EXCHANGER REMOVAL 1. Shut water, gas and electricity off, close valves and relieve pressure, remove relief valve. Remove side inspection panels. 2. Remove top holding screws. 3. Remove draft diverter, lift and remove top and flue collector on stack-type models. Remove inspection panels. 4. Loosen bolts and disconnect flange nuts on inlet/ outlet header, loosen union(s) at gas pipe and slide boiler away from piping until studs clear the header. 5. Remove combustion chamber clips at the four corners of the heat exchanger. 6. Lift heat exchanger straight up using caution not to damage refractory. 7. Reverse above procedure to reinstall. CONTROL IMMERSION WELL REPLACEMENT 1. Shut water off to heater and drain heat exchanger. 2. Remove jacket top panel. 3. Remove old control well with bushing and sleeve, with 7/8" wrench or socket. 4. Slip "O" ring gasket over control well and install in header. "O" RING GASKET WELL ASSEMBLY Fig. # 8101.0 UNITHERM GOVERNOR (U.G.) REPLACEMENT 1. Shut water, gas and electricity off, close valves and relieve pressure. 2. Drain heat exchanger. 3. Remove retainer plug located under outlet pipe connection. 4. Remove spring and replace old U.G. with a new U.G. 5. Reverse above procedure to re-install. GASKET U.G. RETAINER PLUG SPRING FIig. # 8071.0 To test the operation of the Unitherm Governor, place in hot water (over 110 °F) and watch for movement against spring. If there is no movement, replace unit. TUBE CLEANING PROCEDURE (Typical) Establish a regular inspection schedule, frequency depending on local water condition and severity of service. Do not let the tubes clog up solidly. Clean out deposits over 1/16" in thickness. The heater must be cleaned from the rear as shown. It is preferable, however, to remove the heat exchanger and the in/out header 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 heat exchanger, generally. 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. Fig. # 8128.0 25 TUBE REPLACEMENT PROCEDURE Tube replacement may be effected 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 severed, 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; ...