Fan duration to determine when to change filter

[TimR]

There's a reason it isn't common to have run time easily available.

It would show how badly sized some systems are.

[CRNG]

On Mon, 16 Nov 2015 13:44:45 -0600, [e-mail] wrote in

+1

[DerbyDad03]

st indication whether your equipment is sized properly, and that will let y ou be sure of the right size when it comes time to replace.

What does a thermostat's run time tracker actually measure? If all it measu res is *fan* run time, it will tell me nothing about whether my furnace is sized correctly o r not.

I often run my fan 24 x 7 to keep the air circulating.

ning to the air flow across the filter - when it starts to get a bit louder I replace. When my hearing fades (I'm getting up there in age) I'll just start changing every two months again.

[Micky]

I bought one of those, but then when I tried to slide the filter into the filter holder, the whistle made it an inch too thick. If I cut the whistle shorter, I think it would have fallen out of place. How do people get the whistle into the air stream?

See below.

I guess these answer that question.

[TimR]

And if all it measures is compressor time, it will tell you very little about your filter.

But I don't really care about the filter. I change it by the time, or when I hear the air flow sound change, whichever comes first.

I don't have a thermostat with a run time tracker and in fact have never seen one. So we need someone to tell us how they are programmed. In theory I don't see any reason why they couldn't track either fan or compressor, or both.

If your AC equipment is running 10% of the time on a hot day, it's too big. If it's running 100% on a mild day, it's too small. Ideally it would run 100% on your peak days and not quite keep up.

[trader_4]

Well, seems he's talking about people who don't run it 24/7, which would be most of us. Or people who at least don't run the fan separately while doing the test. You don't need to do this for months. You just need to do it one day when it's one of the coldest or hottest days. But I can get a general feel for it without the thermostat having an hour timer, just from observing how long the furnace is running for an hour, without even using a watch. Beyond some general observation, probably not much value in more refined data because IDK from that how you're going to pin down that it's oversized by XX BTU anyway. But it could be useful so that if you have say a 100BTU, you know that you can go down one size. It also assumes that the existing furnace is working at it's rated efficiency, etc.

[trader_4]

I've had a programmable where it tracked fan time. It was specifically there for what the OP is talking about, it's the filter change reminder. You could set the number of hours, it counts down, when it expires it puts up a flashing filter change indicator.

Never saw one that tracked furnace or compressor run time. The filter change angle is the only real use I see, based on fan time.

Say what? Run 100% on peak days and not keep up? Who would want that? Also, with undersizing it's not just the keeping up, it's the recovery time. I want a system that doesn't take all day to heat or cool the house and get it back to desired temp when it's been setback.

[trader_4]

Yeah, I'm sure the thermostat manufacturers all have that in mind.... Or it could be that they figure that consumers wouldn't use it, don't need it, how would they explain what it's for, etc..... A filter change indicator based on fan time, that I can see some consumers thinking they could use.

[DerbyDad03]

Wait...I'm confused. You were the one that said "I'm one who thinks run time is a useful measurement. It gives you the best indication whether your equipment is sized properly..."

Yet it appears that you don't know what "run time" is actually measured, so you don't really know that "It gives you the best indication whether your equipment is sized properly".

Do I have that right?

[bob haller]

they sell a whistle that goes into the filter, when the filter gets clogged the whistle blows

[Stormin Mormon]

If you ever find a URL, I'd love to see that. Sounds like a good idea.

- . Christopher A. Young learn more about Jesus .

. .

[DerbyDad03]

Micky already posted a few links for items as cheap as $3.99 for a simple whistle to over $80 for a fancy-a$$ electronic sensor.

Look up thread a few posts.

[Ed Pawlowski]

Mine just tracks "on" time. Hours for the day, hours total. There may be more sophisticated models though.

[DerbyDad03]

What does "on" mean?

Burner on (which probably means blower on) or blower on only, i.e. Fan switch set to ON?

[Ed Pawlowski]

On = calling for heat. I have HW so it means the circulator for that zone is working but the burner cycles as needed. Used on a hot air system, same thing, just calling for heat.

[Unquestionably Confused]

Suspect that you would want it tracking the run time for the blower itself since, as long as it's running, it's doing its part to clog the filter/air cleaner. If he doesn't need something fancy to graph the use, hours per day, peak hours, etc. a simple hour meter connected to the motor should do it.

Record the hours when you change out the filter, etc. It ain't classy, but it works.

[Unquestionably Confused]

Forgot to add, that the blower runs longer than the burners in every system I've ever seen in order to keep the plenum (?) from getting too hot and warping or whatever. Which is why tracking the blower on state is going to give you the results desired... or should

[trader_4]

The thermostat I had tracked fan time, it was specifically for tracking filter replacement.

[bob haller]

amazon has several filter clogged whistles, cheap too

[Tony Hwang]

Visual inspection is too bothersome for you? I just replace twice a year. Seems to be doing fine. Filter is 16x2x5 pleated filter at MERV 10.