Middleby Marshall PS200, PS570, PS360, PS555 Blower belt tension and repositioning the blower motor

4.Blower belt tension

NOTE: Middleby recommends checking the blower belt condition and tension every three months.

Check the blower belt for at least 1" / 25mm deflection at the center, and for cracking or excessive wear. Overtightening the belt will cause premature bearing failure and possible vibrations. See Figure 47.

If necessary, adjust the tension of the belt by loosening the two motor mounting bolts as shown in Figure 47. Reposition the motor as neccessary until the correct deflection is reached, then tighten the bolts.

5.Bearing replacement and alignment

Whenever service to the blower shaft or replacement of the bearings is required, the shaft will need to be aligned.

NOTE: Apply anti-seize compound (MM P/N 17110- 0017) to all bolts before installing back wall assembly to oven.

First, reassemble the back wall components, but DO NOT TIGHTEN THE HEX BOLTS that hold the bearings to their mounting brackets. Leaving the bearings loose allows the pulleys to be aligned.

Next, check the alignment of the pulleys using a cord as shown in Figure 48. Reposition the bearings as required to align the blower shaft, then tighten the hex bolts to hold the shaft in place.

Replace the belts and rear shrouds after the pulleys are properly aligned.

SECTION 3 - SERVICING COMPONENTS

Figure 47

Blower belt tension and

repositioning the blower motor

PS570,

PS570S

1” (25mm)

vertical

deflection

PS570G,

PS555

Loosen bolts to reposition motor and adjust belt tension

Figure 48 - Four-point alignment test for correct pulley alignment

Cord tied to shaft

Cord must touch sheaves at four points indicated by arrows

79