750-96 (revised 2010)
Model CB Packaged Boiler Manual
7-17
7.15 — Air Pump and Lubricating System
A properly aligned coupling will last a long tie and will provide trouble-free mechanical operation.
7.15.8 — Air Pump Replacement
Use the following procedures to replace the pump, and be sure to tag the motor leads, if disconnected, to simplify
reconnection.
Dismantling
1. Lift out the two front cylinder pins that hold the screen and remove the screen.
2. Disconnect the flared nut on the tubing (behind the screen) and lift the tubing high enough to prevent drainage
of lubricating oil from the tank.
3. Disconnect the flared nut at the orifice fitting.
4. Remove the two sheet metal screws that hold the cylinder in place. One screw is located at the top rear of the
cylinder, the other is at the bottom front.
5. Remove the entire heat exchange assembly consisting of the cylinder, the finned tubing, and the oil line.
6. Remove the fan from the air pump.
7. Disconnect the flexible air line from the lube tank.
8. Remove the coupling guard by pushing in on both sides until it clears the clamp.
9. Loosen the clamp at the rear of the tank and remove the tank with the copper tubing attached,
10. Leave the rear pump bracket (coupling end) in place to aid in realignment of the replacement pump. Do this by
removing the two cap screws that extend through the bracket into the pump housing. Temporarily leave the
front bracket attached to the pump.
11. Remove the screws holding the front bracket to the base and lift off the pump with its attachments. Note the
location of the pipe fittings and brackets prior to removing for installation or the replacement pump. If the pip-
ing is dismantled, be sure that the check valve is reinstalled so that the gate swings towards the pump.
Reassembly
Reassembly should take place in reverse order of disassembly. With the rear pump bracket left in place, realign-
ment and spacing between the pump shaft and the motor shaft is greatly simplified.
There should be approximately 7/8” space between the two shafts. Place the coupling insert between the coupling
halves prior to reassembly. Check to see that both shafts rotate freely.
If shims were used originally under either pump brackets or motor feet, be sure that they are correctly reinstalled.
When reinstalling the fan, slide the hub on the pump shaft so that it is bottomed. Tighten the setscrew and cap-
screws. If the fan blades were removed from the hub, make sure that the side of the blade marked “Blower” faces
the hub when reassembling. When tightening the coupling halves or the fan hub, tighten the setscrews against the
key first, then tighten the setscrew against the shaft. Clean or remove any dust or grime from the blades prior to
reinstalling.
When replacing the retainer screen, a slight force may be required to push the cooling coil into the air cylinder so
that pins may be fitted into place.
Make sure that all piping connections are tight.
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