Carrier® Dedicated Outdoor Air Unit 62X: Quarterly Maintenance

In the event that routine quarterly inspection indicates that there is dirt or dust buildup within the wheel causing an excessive pressure drop, then wheel cleaning should be performed as follows:

• Using a standard shop vacuum, vacuum any debris from both faces of the wheel. Slowly work around the entire face of the wheel to complete the procedure. Do not damage wheel face by excessive pressure of the vacuum nozzle on the wheel face.

• Using 20 psi clean, dry air and a small air nozzle, blow air through one face of the wheel. At a similar location on the opposite side of the wheel, gently apply a shop vacuum to “receive” any remaining debris exiting the wheel. In the event that this method does not remove visual buildup or return pressure drop to within normal parameters, a wheel washing procedure is recommended. The energy conservation wheels can be washed thoroughly with water without affecting the performance of the wheel. The wheel will simply dry out following a washing procedure and resume normal energy transfer without any deviation in performance. If the energy conservation wheel can be easily removed from the cassette or unit, it is recommended to do so to facilitate the washing process. However, in most cases, it is impractical to remove larger wheels. Therefore, the washing procedure must take place within the air handling unit, and provisions need to be made to collect the runoff water from the bottom of the unit or collect the water by using a wet vac on the opposite side of the wheel during the procedure.

• Shield all electrical components and bearings with plastic sheeting. Ensure that an adequate drainage system exists to collect runoff water from the bottom of the unit. Alternatively, use a wet vac with a wide nozzle on the opposite face of the wheel to collect the water during the washing procedure.

• Disable the drive motor.

• Using standard pressure water (do not use a high pressure washer) and working from the one side of the wheel, wash the wheel with a standard “garden” nozzle to flush any debris trapped within the flutes of the wheel. If desired, a mild detergent can also be used to enhance cleaning without affecting the performance of the wheel.

Check for gas leaks

Check for gas leaks.

Check for cracked ceramics, excessive carbon residue, or erosion of the electrode. Replace as required.

Check that gas valve seat is not leaking.

Soft brush or vacuum inside burner, at burner ports, and at air inlet between burner and manifold pipe to eliminate accumulation of lint and/or dirt.

Inspect for cracks, sagging, bending, or distortion. Clean with vacuum and/or stiff brush.

Clean with compressed air or vacuum.

Venting must be intact. Using a flashlight, look for obstructions, cracks on the pipe, gaps in the sealed areas, or corrosion. Clean vent terminal.

Check for blockages.

Check all wiring connections. Tighten as necessary. Check internal wiring. Replace as necessary with type THHN 221°F (105°C), 600V, 16-gauge wire or equivalent.

Check heater control panel for dust/dirt and moisture. Clean as necessary.

Check heating elements for dust/dirt buildup and/or broken elements. Replace elements and/or clean elements with low pressure air as necessary. Check element male/female chassis insulators for breaks and/or cracks. Replace as necessary. Check element support frame insulators. Replace missing or broken insulators as necessary

Filters should be checked for dirt restriction on a monthly basis (or as required). Replace filters with filters of equal specification when they appear dirty.