HVAC service call inspection minimums
Asking this question as a builder. Trying to write up the minimum expectations for a service call for an HVAC contractor. Having issues where customers have complained about comfort and the subcontractor has done a service call, said everything checks out, only to have the customer complain that not much was actually done by the tech, including checking airflow, etc. I’ve found the sub’s standard checklist less than ideal.
So trying to come up with minimum expectations of what should be done to validate that a system is performing as expected on a service call. My online searches haven’t been very fruitful, and I’d like to hear from others before just offering my own color on this. I have high efficiency gas furnaces paired with condensers typically, but do have the occasional heat pump and some mini-splits. With rare exceptions, all duct work is within the envelope.
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This mostly from my experience troubleshooting older furnace installs. Not a pro, just do this when a call to the HVAC tech failed to fix issues.
Minimum would be to measure flow and temperature at each register. This will tell you right away if you have a problem.
I usually measure also measure pressures at the return plenum, after the filter, after blower and after coil. Also good to check temperature drop/rise across the air handler at the same time both for heat and cool. Measuring flow is also a good thing, lot of times the issue could be as simple as jumpers not set correctly or thermostat/furnace stages miss wired.
Generally getting those measurements will tell you right away where the problem is. Once you see them, it is hard to say "everything is fine".
If you have any reason to suspect a refrigerant leak, have them wand the A coil and condenser. The sands are like electronic noses that sniff out refrigerant. They are very sensitive, and if they are used BEFORE running the air handler, they should alert you to any leaks. It’s a quick test and should be cheap.
Check for any water issues around the heat exchanger too. I’ve seen heat exchangers rot out, and damage control boards too, caused by nothing more than a loose fitting drain hose.
Bill