I now do, pro bono, a triage for the local senior center support program. (it's been over 100 in this are for weeks). The only tools I have are a VOM, Amp meter and a set of Xcellite spin tight hand tools that come in a blue roll up kit. I fix the obvious, tripped breakers, flooded drip pans, diagnose blower/condenser fan problems. Remove bugs from contactors etc.
Anything more is handled by a phone call to the outreach group and occasionally a discussion with the 'real' tech with an eye to getting the cool back on.
I've been talking to the techs that the outreach group pays to fix the real problems. they have tried to explain to me how to property check if the R410A system is low and more so the process used in 'toping off'.
Seems I'm too dense to understand what I've been told.
My question is there a web site, book or other source of information that can give me a better understanding of what's involved from a practical point of view. I figure if I can plow through that I should have a better basis to understand what the techs are trying to tell me.