Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual

Also see for 48PG20---28: User's information manual User's information manual Controls, start-up, operation, service and troubleshooting instructions

Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual Manual pdf 47 page image

475. Thoroughly apply Totaline® environmentally sound coilcleaner solution to all coil surfaces including finned area,tube sheets and coil headers.6. Hold garden sprayer nozzle close to finned areas and ap-ply cleaner with a vertical, up-and-down motion. Avoidspraying in horizontal pattern to minimize potential forfin damage.7. Ensure cleaner thoroughly penetrates deep into finnedareas.8. Interior and exterior finned areas must be thoroughlycleaned.9. Finned surfaces should remain wet with cleaning solutionfor 10 minutes.10. Ensure surfaces are not allowed to dry before rinsing. Re-applying cleaner as needed to ensure 10-minute satura-tion is achieved.11. Thoroughly rinse all surfaces with low velocity clean wa-ter using downward rinsing motion of water spray nozzle.Protect fins from damage from the spray nozzle.CONDENSATE DRAIN — Check and clean each year at thestart of the cooling season. In winter, keep drains and traps dry.An access panel is located above the condensate connection toallow easy clean out of the condensate pan. The first time thepanel is removed, the insulation behind the access panel willneed to be cut away. Carefully cut the insulation with a knife orblade on three sides so the insulation can be folded out of theway during cleaning. Be careful not to damage components be-hind the insulation while cutting. Once cleaning is completed,fold the insulation back into place and secure the access panelin the original position.FILTERS — Clean or replace at start of each heating and cool-ing season, or more often if operating conditions require. Referto Table 1 for type and size.OUTDOOR-AIR INLET SCREENS — Clean screens withsteam or hot water and a mild detergent. Do not use throwawayfilters in place of screens. See Table 2 for quantity and size.MAIN BURNER — At the beginning of each heating season,inspect for deterioration or blockage due to corrosion or othercauses. Observe the main burner flames. Refer to Main Burn-ers section on page 51.FLUE GAS PASSAGEWAYS — The flue collector box andheat exchanger cells may be inspected by removing heatsection access panel (Fig. 4), flue box cover, and main burnerassembly (Fig. 31). Refer to Main Burners section on page 51for burner removal sequence. If cleaning is required, cleantubes with a wire brush.Use caution with ceramic heat exchanger baffles. When in-stalling retaining clip, be sure the center leg of the clip extendsinward toward baffle. See Fig. 32.COMBUSTION-AIR BLOWER — Clean periodically to as-sure proper airflow and heating efficiency. Inspect blowerwheel every fall and periodically during heating season. For thefirst heating season, inspect blower wheel bi-monthly to deter-mine proper cleaning frequency.To inspect blower wheel, remove heat section panel. Usingan inspection mirror and flashlight, look into the flue exhaustduct to inspect the wheel. If cleaning is required, remove motorand wheel assembly by removing the screws holding the fluebox cover to the flue box. See Fig. 31. Remove the screws hold-ing the inducer housing to the inlet plate. The wheel can then beremoved from the motor shaft and cleaned with a detergent orsolvent. Replace the wheel onto the motor shaft in the correctposition and reassemble the flue cover onto the flue box.LubricationCOMPRESSORS — Each compressor is charged with thecorrect amount of oil at the factory.Polyolester (POE) compressor lubricants are known tocause long term damage to some synthetic roofing materials.Exposure, even if immediately cleaned up, may cause roofingmaterials to become brittle (leading to cracking) within ayear. When performing any service which may risk exposure ofcompressor oil to the roof, take appropriate precautions toprotect roofing. Procedures which risk oil leakage include com-pressor replacement, repairing refrigerant leaks, and replacingrefrigerant components. To prepare rooftop:1. Cover extended roof work area with an impermeableplastic dropcloth or tarp. Make sure a 10 x 10 area aroundthe work area is covered.2. Cover area in front of the unit service panel with a terrycloth shop towel to absorb lubricant spills and preventrun-offs. Towel will also protect dropcloth from tearscaused by tools or components.3. Place terrycloth shop towel inside the unit directly undercomponents to be serviced to prevent spills through thebottom of the unit.4. Perform the required service.5. Remove and dispose of any oil contaminated material perlocal codes.The compressor is in a Puron® refrigerant system and usesa polyolester (POE) oil. This oil is extremely hygroscopic,meaning it absorbs water readily. POE oils can absorb15 times as much water as other oils designed for HCFCand CFC refrigerants. Avoid exposure of the oil to theatmosphere. Damage to components could result.CERAMICBAFFLECLIPNOTE: One baffle and clip will be in each upper tube of the heatexchanger.Fig. 32 — Removing Heat Exchanger CeramicBaffles and ClipsHEATEXCHANGERSECTIONIGC BOARD(HIDDEN)COMBUSTIONFAN HOUSINGMAIN BURNERSECTIONINDUCEDDRAFTMOTORMAIN GASVALVEFig. 31 — Typical Gas Heating SectionIGC — Integrated GasController