Desa NTH100-2, NTH50-2, NTH35-2, NTH150-2, NTH70-2 Pump Rotor, Procedure if Rotor is Binding

PORTABLE FORCED AIR HEATERS

SERVICE

PROCEDURES

Continued

PUMP ROTOR

(Procedure if Rotor is Binding)

1.Remove upper shell (see page 8).

2.Remove filter end cover screws using 5/16" nut-driver.

3.Remove filter end cover and air filters.

4.Remove pump plate screws using 5/16" nut-driver.

5.Remove pump plate.

6.Remove rotor, insert, and blades.

7.Check for debris in pump. If debris is found, blow out with compressed air.

8.Install insert and rotor.

9.Check gap on rotor.Adjust to .076/.101 mm (.003"/.004") if needed (see Figure 25).

Note: Rotate rotor one full turn to ensure the gap is .076/.101 mm (.003"/.004") at tightest position. Adjust if needed.

10.Install blades, pump plate, air filters, and filter end cover.

11.Replace fan guard and upper shell.

12.Adjust pump pressure (see page 10).

Note: If rotor is still binding, proceed as follows.

13.Perform steps 1 through 6 above.

14.Place fine grade sandpaper (600 grit) on flat surface. Sand rotor lightly in “figure 8” motion four times (see Fig- ure 26).

15.Reinstall insert and rotor.

16.Perform steps 10 through 12 above.

BladeAir

Pump Intake

Plate Filter

Filter End

Cover

Fan Guard

Insert

Rotor

Air Output

Filter

Figure 23 - Rotor Location, 35/50/70,000 Btu/Hr Models

Blade Pump

Plate

Air Intake Filter

Filter End

Cover

Fan Guard

Insert

Rotor

Air Output

Filter

Figure 24 - Rotor Location, 100/150,000 Btu/Hr Models

Gap Adjusting

Screw

Blade

.076/.101 mm (.003"/.004") Gap

Measured With Feeler Gauge

Rotor Sandpaper

Gap Adjusting

Screw

Figure 25 - Gap Adjusting Screw Locations

Figure 26 - Sanding Rotor

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