I agree that maintenance contracts are not cost effective to anyone who has basic mechanical abilities (that would be ~95% of the members on this board).
Yes - that I agree with in principle.
In case anyone is interested, here is the procedure used by many HVAC technicians to perform an annual maintenance service on a gas furnace:
Most of your list is NOT going to prevent a failure. I'll dissect one at a time ...
- Check operation of thermostat functions.
Doing "checks" is just moving the switches or pushing buttons. None of which does anything "preventative" in terms of preventing a future failure. Anytime a homeowner touches the thermostat they essentially do the same thing. This is a "feels good to watch him touch the device" item. It prevents or fixes nothing. If the thermostat were to fail at some point in the future, nothing the tech did was going to prevent it by "checking it".
- Check operation of emergency cut off switch.
Again, checking a switch does what, exactly? How many times do techs find a bad "emergency switch"? And what is an "emergency switch" anyway? Are you speaking to the service switch on the side of the furnace that cuts power to the unit for work? And just how is it that a homeowner can't check the function of a switch (presuming it's exterior to the unit)?
- Vacuum or blow out dust within the air handler cabinet.
This is a feel-good item; it does nothing to prevent a failure. Dust isn't the cause of any major failure modes.
- Inspect air filter(s) and replace as necessary.
Man oh man, if a homeowner can't change their own filter, then they should live in a condo where all maintenance is included.
- Test continuity/operation of access door safety switch.
Again - what failure mode does this prevent? If the switch is closed, the furnace runs. Assuming the homeowner isn't just taking the door off and defeating the switch for the joy of running the furnace, why is this a service worth paying for? And how many times has a bad switch been discovered? This is probably one of the lowest failure modes of any furnace malfunction. If the door is on, and the furnace runs, then leave it alone!
- Investigate any trouble codes displayed on the IC control board LED.
Those trouble codes are very helpful when there's a problem. When there's a problem, a service call is very prudent. But assuming all is running well, there will be no problems with the furnace, and hence no codes present, and therefore no need for a service call, which means no service tech. Including this in the "preventative maintenance contract" has ZERO gain for the customer.
- Clean soot from the flame sensor wire probe (and spark igniter, if equipped).
Yes, this can be beneficial. But, it may not be necessary for a decade or longer (my example of 16 years with no issues). Why have an annual service contract for something that may not happen but once a decade?
- Verify proper operation of exhaust gas induction blower and vent stack not blocked.
All modern furnaces have safety protocols written into their operational logic that does this by looking at the pressure differential at the pressure switch, inducer amps, etc. A service tech is only going to watch the furnace go though it's ignition sequence and if it's all good, he does NOTHING else. If something is wrong, then the furnace will set a code and the code can be read by the tech. Again, a service call would be prudent, but a maintenance contract doesn't prevent any failure here.
- Test operation of induction blower vacuum sensor diaphragm (by disconnecting and sucking on rubber tubing).
Aka the pressure switch. It either works or it doesn't. Yet again, the furnace has programming to detect the failure; it won't make the dP if there's a leak.
The only "preventative" measure would be a true part replacement. This would be like changing out a fuel line on a car even if no evidence exists to warrant the change. By the way, this "diaphragm" test is assured in the above "induction blower / vent stack" test. These two items are all part of one sequence test in the furnace upon start-up.
- Check continuity on the rollout flame sensor and various bi-metallic switch overheat sensors.
Again, the furnace already does this as part of the fire-up sequence. There's nothing to "check"; all the tech is going to do is watch the furnace run a full cycle. There's nothing "preventative" about this tech service. The furnace will fault out if the circuit isn't working. There is NOTHING he can "observe" in a "check" that would indicate a looming failure. The circuit either works or it doesn't. There is no "check" a tech will do other than sit and watch it work as it should. You can check continuity; who gives a crap? The fire-up sequence logic in the control board does this each and every time it gets a call for heat. If the circuit is close, it continues to go through the sequence. If the circuit is open, it sets a trouble code. There is NOTHING a tech can do during a "continuity check" that would prevent a future failure. The furnace will do that every heat cycle anyway.
- Visually inspect gas burners and heat exchanger.
Inspection would be looking for debris in the burners. This is very rare. It can be beneficial, but it's not really necessary. As for the burner, it's common for the tech to say "you have cracks in the heat exchanger; that's bad". But in reality, cracks are very common and most often a non-issue. Inspecting for these things typically leads to a tech recommending a replacement of something that doesn't need replacement. It is, at its core, a sales push tool.
- Verify the operation of the hot-surface igniter.
Again, "verify" means watch it do its job. Or it doesn't, which would mean a service call is warranted. But a "maintenance" call does nothing to prevent this from failing in the future.
- Observe flame pattern and color.
There's no adjustment to flames these days. Way back when, there were intake-air-slide adjustments that could be made. Not any longer; not for a long time now. The burners are fixed in their manufactured state. Observing them can only confirm a manufacturing defect; then a replacement would be warranted. If no defect, there's no need to "observe" this more than once. And in theory, the installer should have checked the initial operation. About the only thing that can affect the flame is to have an insect crawl into a burner and block the orifice or ceramic gas block; rare indeed.
- Verify normal operation of (single speed, 2 speed, variable) air handler blower fan.
Over and over, we're at the same point. Observing does nothing. The system either works or it doesn't. Observing the "normal operation" does not mean it will prevent a failure a month after the "inspection". Watching the blower ramp up/down today does not prevent a failure tomorrow. Observations do nothing. If the unit is malfunctioning at the current state, a service call is prudent. But a "preventative maintenance check" does zilch here.
- Inspect physical condition of starter capacitor(s).
Perhaps one of the few logical uses here. But this would be like the burner crack issues; the tech is likely to recommend replacement of perfectly operational caps just to cover his/her butt and also make a profitable sale.
- Flush out condensate discharge PVC pipe with bleach and water.
This is of value in some circumstances, but not others. Not all discharge pipes need help, but some do.
- Check freon pressures and compressor operation on condenser unit if Heat Pump/Dual Fuel unit.
Pretty much going to watch it run ... it works or not. If low on refrigerant, they'll top it off. End of story.
My point is that many of these "maintenance contracts" are very expensive, and yet provide very little ACTUAL, ACTIONABLE work. Most of it entails watching the unit run, and it's all good, and thank you for your $expensive annual maintenance payment. Plus, if something is verifiably wrong, they owner still has to pay for the labor and part for a fix, which would be no different than if the unit had an error or stopped and they had a "service call" rather than a "preventative maintenance call".
I worked at a major OE HVAC maker for 16 years, in the plant that made all the furnaces and fan coils, as a quality control engineer at first, then into other engineering assignments. For a time, I worked directly over the furnace and coil lines. I know them inside and out. I can tell you with certainty that MOST of the preventative checks you mention are bogus feel-good actions that have no bearing on how things run, and no true preventative value. Most (not all) of the items on your list are either useless, and those that aren't useless could easily be done by any homeowner after watching a YT video. Maintenance contracts are a big money maker for service entities; they are an insurance policy that you're going to be ripped off.
What I might agree with is that doing all those things you list perhaps once after the first 10 years, and then again every 5 years thereafter; that might be OK. But my objections are based on these "annual maintenance contracts" that have a fixed cost (typically $200-$400 annually) that do essentially nothing to prevent a failure. I am not saying doing some checks is not worthwhile. I'm saying the annual maintenance contracts have a very low ROI; typically, they just result in some part being replaced as a "preventative" measure when the part wasn't failing anytime soon.