General • Inspections

Lennox CB17/CBH17-95/135/185/275 Blower Coils: Maintenance

This maintenance procedure and service must be performed by a qualified installer or service agency. This procedure focuses on checking your equipment's outdoor unit, how to clean and inspect the outdoor coil. Following the recommended maintenance procedure will help you maintain the superior efficiency of your unit for a long period of time.

MaintainX

08/10/2022

Lennox CB17/CBH17-95/135/185/275 Blower Coils: Maintenance

Adjusting Belt Tension

Maximum life and wear can only be obtained from belts if proper pulley alignment and belt tension are maintained. Initially tension new belts at the maximum deflection force recommended (1/64 inch per inch of span), and then re− tension belt after 24−48 hour run period. This allows belt to stretch and seat in grooves.

To remove or tension belt, loosen the bolts on the hinged motor cradle and slide up or down.

Check Belt Tension

Overtensioning belts shortens belt and bearing life. Check belt tension as follows:

Measure span length X. See figure 2.
Apply perpendicular force to center of span (X) with enough pressure to deflect belt 1/64" for every inch of span length or 1.5mm per 100mm of span length. Example: Deflection distance of a 40" span would be 40/64" or 5/8". Example: Deflection distance of a 400mm span would be 6mm.
Measure belt deflection force. For a used belt, the deflection force should be 5 lbs. (35kPa). A new belt deflection force should be 7 lbs. (48kPa).

A force below these values indicates and undertensioned belt. A force above these values indicates an overtensioned belt.

REFRIGERATION SYSTEM

The coil is divided into two sections. The lower portion is first stage and the upper section is second stage. Each section has its own liquid line connection and expansion valve or valves. This configuration allows the use of a solenoid valve to control the flow of refrigerant into one coil section. Use this feature for capacity reduction or latent heat control. If a solenoid valve is used, install it directly ahead of the expansion valve of the coil section being controlled. Size the solenoid valve for ap

The expansion valves are sized specifically for the two stages. The CB17/CB17H−95−2 units have 4 ton first stage expansion valves and 3 ton second stage valves. The CB17/CB17H−135−2 units have 5 ton first stage expansion valves and 4 ton second stage valves. The CB17/CB17H−95−3 units have 6 ton first stage expansion valves and 4 ton second stage valves. The CB17/CB17H−135−3 units have 6 ton first stage expansion valves and 4 ton second stage valves.

The CB17/CBH17−185 has a 7−1/2−ton first− and second− stage expansion valve. The CB17/CBH17−275 has two 5−ton first− and two 5 ton second−stage expansion valves.

Refrigerant lines or stubbed for sweat connections and are located inside the unit cabinet. See figure 1.

CONDENSATE PAN

Two drain outlets are provided, one per side. Never connect condensate drain to a closed system. Condensate drain line must have a trap in the line at the unit exit.

Source: MaintainX (Community Member)