Thomas & Betts RZ-NA 441-OMS Drive Components, 1A. Blower Bearings, 1B. Blower Belts, Filters

R1. Drive Components

The blower, motor and drive components are located in the blower cabinet at the top of the system. Systems with horizontal discharge have a cabinet with eight removable door panels. Systems with vertical discharge have a cabinet with six removable door panels. Remove the panels required to access the components being serviced.

1A. Blower Bearings

All blowers are Class I with pillow block bearings. Clean the fitting and add type NLG-2 or -2 standard grade grease. Add grease with a handgun until a slight bead of grease forms at the seal. Be careful not to unseat the seal by over lubricating.

NOTE: If unusual environmental conditions exist (temperatures below 32oF or above 200oF; moisture; or contaminants) more frequent lubri- cation is required.

CAUTION: If the blower is unused for more than three months, the bearings should be purged with new grease prior to startup.

Recommended Bearing Lubrication Schedule in Months

	Bearing Bore Diameter (Inches)
RPM	1/2	>1 to	>1-1/2 to
	to 1	1-1/2	1-15/16
to 500	6	6	6
501 - 1000	6	6	6
1001 - 1500	5	5	5
1501 - 2000	5	4	5

1B. Blower Belts

Check belts for proper tension and wear. Adjust belt tension as needed. Replace worn belts.

Proper belt tension is important to the long life of the belt and motor. A loose belt will cause wear and slippage. Too much tension will cause

excessive motor and blower bearing wear. If adjustment is required, adjust belt tension by means of the adjusting screw on the motor base until the belt can be depressed 1/2" to 3/4" (Figure 2). Tighten the lock nut on the adjusting screw. Be sure the belt is aligned in the pulleys.

Figure 2 -
Belt	3/4” (19mm)
Tension

R E 2. Filters

If the system includes filters, check the filters quarterly. Filters could be either in the optional inlet base or in an optional filter cabinet.

If the filters are in the perimeter of the inlet base; they are two-inch permanent filters. Remove and clean the filters as needed.

If the filters are in a filter cabinet (the filter cabinet is always between the inlet base and the burner/control section), remove the filter cabinet door panels to access the V-bank filter rack. Filters may be either 2" disposable, 1" or 2" permanent, or 1" or 2" disposable pleated. Clean or replace as needed.

Sizes and Quantity of Filters in the Filter Cabinet

( same for all types of filters)

Size	109	112	115	118	122	125
16" x 16"	4	4	-	-	16	16
16" x 20"	4	4	6	6	-	-
16" x 25"	-	-	6	6	8	8

S3. Manifold Gas Pressure

Semiannually, check the gas pressure to the burner and to the pilot. Measure both manifold pressure and pilot supply pressure with the blower in operation. Refer to Figure 3 for pressure tap locations. Verify against pressures listed on the rating plate.

Figure 3 - Location of

pressure taps for		Pilot	Pilot Solenoid Valve
	Pilot Manifold	Regulator
measuring burner and
pilot gas pressure.
Measure with blower			Pilot Pressure Tap
operating.

Valve	Valve	Regulator	Manifold Pressure Tap
Gas
Supply
Inlet Pressure Tap

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