Light Commercial PM Procedures
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First, you will want to make sure you and the customer are clear on the agreement. Then, you can start the PM with a thorough visual inspection. Lower the thermostats, test the float switches, and take copious notes about things that look concerning. Unlevel or insecure condensers are also major issues.
Once you’ve done a visual inspection, you can start cleaning the condensers; your readings will reflect system performance more accurately if the condenser is clean and allowed to reach its full potential. When cleaning a condenser, try to use only water when possible; otherwise, you may need to use a safe cleaner. When cleaning microchannel coils, be especially careful about water pressure and chemical usage. RTUs may also have split coils with multiple rows; those need to be separated and cleaned.
Check the electrical components of the condenser. Make sure the wires are neat and have tight connections, and make sure your readings are within their appropriate ranges. This is also the time to check the capacitor and make sure it doesn’t need to be replaced. Amp draw is another critical electrical reading. When you need to replace the electrical panel and condenser top, make sure you use all the right screws and make sure everything is secure.
Then, you’ll want to check your system’s refrigerant temperatures and pressures. Check the superheat, subcooling, and pressures throughout the system and record those. Once you finish doing everything you need to do outdoors, go indoors and check the filter. Replace it in accordance with your agreement; in our case, we write the changeout date on the filter. We check to make sure we can safely insert and remove the filters, and we may need to present solutions to the client, even if we need to propose costly solutions like making modifications to the system if we can’t safely access, add, or remove the filter.
Do another visual inspection at the air handler, paying special attention to blower wheel cleanliness, panel insulation, and wire routing and connections. You’ll also want to clean the drain pan; whatever is in the pan will eventually find its way into the drain line, so the pan MUST be cleared of any debris. When cleaning drain pans, you’ll want to run water through the pan and the drain until the water is completely clear.
When cleaning the evaporator, we want to try to stick with water or self-rinse cleaners. We want to make sure that we use very mild chemicals, and any foaming cleaners should be diluted appropriately and rinsed entirely. In some cases, we may need to pull and clean the blower wheel; you can quote for this if it isn’t in your agreement.
In some cases, you may have to clean a condensate pump or a common drain. The common drain is often the responsibility of the plumber; HVAC technicians should definitely clean the drain leading to the common drain, though. However, you need to know where the common drain leads, so be sure you know where it goes before you use compressed air or cleaners to flush the drain. HVAC technicians do, however, have to clean condensate pumps on PMs.
Also, check for double traps and to make sure that the drain lines are properly pitched, trapped, and vented; vents should be uncapped, but cleanouts must be capped. It’s also a good idea to check the float switches, especially if you have multiple; multiple float switches should be wired in series. At the end, make sure you fill the trap.
Some of the units may have heat strips; we test these during our fall PMs. You just have to be mindful of possible smoking as the dust burns, and you may have to clean those manually before testing them.
When you finish a job, make sure you leave the site exactly as the contract states. Some customers may have specific requests for thermostat settings, so you must heed those. Do a final inspection, make sure all disconnects are back in, clean up all trash and tools, and share any notes with the customer.