Pilot Removal and Cleaning, Heat Exchanger Removal

Main burner and Orifice Removal

1.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.

2.Lift burners from slotted spacer and slide from ori- fices. Clean with a wire brush.

3.Orifices usually do not need to be replaced. To clean, run either copper wire or wood through ori- fice. Do not enlarge hole. To remove orifice, use a socket wrench and remove the manifold. DO NOT overtighten when reinstalling.

Pilot Removal and Cleaning

1.Disconnect pilot tubing at pilot and sensor/igniter wire. Remove screws holding pilot bracket to burn- er tray.

2.Remove pilot and bracket, clean pilot of debris, small bugs, etc., with wire or small brush.

3.Replace pilot, pilot tubing, sensor ignition wires and check for leaks.

High Limit or Tankstat

Removal

1.Turn off electrical power.

2.Remove front inspection panel.

3.Remove wires to high limit and loosen screws holding high limit to cabinet.

4.Remove wedge clip holding sensing bulb in con- trol well.

5.Remove high limit and install a new one.

6.Check control operation before leaving job.

8.Lift heat exchanger straight up using caution not to damage refractory.

Heat Exchanger Re-Assembly

1.Heat exchanger water header O-rings must be replaced with new ones.

2.Install in/out and return water headers and install header retainer nuts and torque nuts evenly.

3.Install the four (4) corner clips between tube sheets and refractory. Replace "V" baffles.

4.Install thermostat sensing bulbs in header wells and replace bulb retaining clips.

5.Install inlet and return pipes in water headers using pipe thread sealant.

6.Install water pressure relief valve, flow switch, and low water cut-off devices (if so equipped).

7.Open water supply and return shut-off valves. Fill heater and water piping system with water. Check heater and piping system for leaks at full line pres- sure. Run system circulating pump for a minimum of 1/2 hour with heater shut-off.

8.Shut down entire system and vent all radiation units and high points in system piping. Check all strainers for debris. Expansion tank water level should be at the 1/4 mark and the balance of the tank filled with air.

9.Install flue collector, jacket top and inspection pan- els. Install top holding screws. Install draft diverter and vent piping if so equipped.

10.If gas piping was disconnected, reconnect gas pip- ing system and check for leakage using a soap solution.

11.Check for correct water pressure and water level in the system. Make sure that system pump oper- ates immediately on the call for heat. The system is ready for operation.

12.Within two (2) days of start-up, recheck all air vents and expansion tank levels.

Heat Exchanger Removal

1.Shut water, gas and electricity off, close valves and relieve pressure, remove relief valve.

2.Remove side inspection panels.

3.Remove top holding screws.

4.Remove draft diverter, lift and remove top and flue collector on stack type models. Remove inspec- tion panels.

5.Loosen bolts and disconnect flange nuts on in/out header, loosen union(s) at gas pipe, and slide heater away from piping until studs clear the heater.

6.Remove heat exchanger corner brackets.

7. Remove combustion chamber clips at the four cor-	Fig. 40: Typical Heat Exchanger Configuration
ners of the heat exchanger.