SECTION 15: REMOVAL AND REPLACEMENT PARTS
SECTION 15: REMOVAL AND REPLACEMENT PARTS
See warnings and notes on Page 43, Section 12 before removing or replacing parts.
15.1 Burner Components
To remove the burner from the heater:
1.Unplug the burner electrical supply from the heater.
2.Isolate the fuel supply at the inlet manual valve and disconnect the inlet fuel pipe.
3.Unscrew the nuts holding the burner mounting flange to the heater.
4.Remove the burner from the heater, retaining the gasket for reuse.
For removal of burner components, follow the manufacturer’s instructions. To refit the burner, reverse the instructions above. Fit the gasket between the burner mounting flange and the heater. Use a new gasket if necessary.
15.2Direct On-Line Main Fan Starter and Thermal Overload Unit (3 Ø)
This assembly comprises two parts, the contactor and the overloads, which may be changed seperately.
15.2.1 The Contactor
To remove the contactor:
1.Remove the overloads as on Page 51, Section 15.2.2.
2.Remove the line connections to the top of the contactor (noting the colour code) and the two coil connections at the top rear of the contactor.
3.Unscrew the fixing screws to remove the con- tactor from the panel.
4.Reverse these instructions to refit. Check rota- tion of the fan after working on the contactor.
15.2.2 The Overloads (models 060 to 100)
To remove the overloads:
1.Unscrew the motor connecting wires from their terminals at the bottom of the assembly. Note the colour code.
2.Disconnect the overload circuit connections near the overload reset button.
3.Disconnect the overload fixing and connecting screws from the bottom of the contactor.
4.Ensure that any replacement overload is of the correct rating and that it is reset correctly. See Page 33, Section 10.1.6.
15.3Control Circuit Fuse (10 or 5 A, 1-1/4" long sand filled)
The control fuse is removed by grasping the centre and pulling it out of the spring clips. To replace, push
a new fuse into the spring clips. To replace the holder, remove the fuse, pull off the two tag connectors from either end, and then unscrew the central screw. Reverse these instructions to refit.
15.4 Combination Fan/Limit Thermostat
To gain access to the thermostat:
1.Loosen the cover retaining screw (on top) and remove cover.
2.Disconnect the electrical connections by push- ing in with a small screwdriver and pulling out the wiring. See Page 52, Figure 22.
3.Unscrew the conduit bush and the two screws and withdraw the unit from the cabinet.
4.Reverse these instructions to refit. See Page 34, Figure 13 to set the new thermostat.
15.5Main Fan Motor (3 Ø Belt Drive)
1.Disconnect electrical connections at contactor and overloads. See Page 51, Section 15.2.
2.For Star/Delta starters, there are six wires between the motor and the starter.
3.Remove the left lower side panel to access the motor.
4.Unscrew the bolts securing the motor to the mounting bracket. Lift the motor out.
5.Reverse these instructions to refit, tensioning the belts as on Page 43, Figure 21 and ensur- ing the pulleys are aligned.
6.For Star/Delta starters, pay specific attention to the six motor connections.
15.6Main Fan Units
Depending on the model of the heater, the main fan unit will be direct drive (with integral motor) or belt drive. Models
To gain access to the fans:
1.Remove the lower side panels of the heater. For models
2.Disconnect the electrical connections. On direct drive units, these will be at the terminal block for single phase and at the contactor for three phase.
3.Remove the screws. The fan will pull out of the heater through the side.
4.Reverse these instructions to refit, tensioning the belts as on Page 43, Figure 21.
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