Is Sense capable of detecting this signature? (strange heat signature)

#1

've got a floor heater that is one of the most important devices i would
like detected. It was detected once (or so i thought) but was very
innaccurate so I deleted it.
I turned it off all day today so it would cool. I then turned it on and the screenshot
shows the signature for the device starting up.
For heat. it looks strange because its not full on. it ramps up to the 540 watts
of power. Its hard to even see on the timeline and does not get tagged with
wattage but when it turns off, its all off instanlty.
The starting up is between the red lines on image.
Is sense capable of detecting such a signature?
I may be able to change how it starts in the thermostat (faster ramp or instant)but the manufacturer is working on the possibility and getting back with me in a few days.

#2

Sense seems to have serious issues with ramps. It’s detected none of my “gradual ramp” devices thus far

#3

I would agree with the ramp comment. My radiant tube heater igniter in my shop ramps up current but no detection with tons of cycles.

#4

After contact with the manufacturer, they were able to see what my original settings were compared to now (after reset).
There is an option in the thermostat to adjust the speed the heat tape starts up. It can be adjusted from 0-99. The reset put it at 5. I went and changed it to 99 to match what I had before. With it now set to 99 it shows on the timeline and does not have the ramp. I’m hoping detection will be possible again for this device. It still does have a stair step look to the waveform instead of the instant on I’m looking for

#5

I am very disappointed in Sense’s lack of ability to recognize very common events.
It’s winter and my heat cycles on and off.
I can hear it, but Sense has no idea what is going on.
I want a smarter and faster detection or allow the user more control to tag loads that are obvious.

#6

How long have you had sense?
Are you using a gas or oil furnace?

#7

Hello,
I have a new Kennox gas-fired furnace.

#8

I think where you have a furnace the first part that will be detected is the ignitor at 300-450 watts. Your blower is probably variable speed so the start signature will be harder to detect.
My heat pump was one of my first detections because of the compressor. It has a very sharp spike at startup and was easy for sense to pick it up. No other parts of my heat pump- air handler combination have been detected yet.

#9

I have a pair of 19 year old Bryant forced air gas furnaces. Sense was able to pick up the blowers after a few months. One thing that I think helped was setting my thermostat to turn on the fan at least 5 min every hour. Also helped distribute the temps and air better throughout the house.

I eventually put both my furnaces on HS110 smartplugs so I can see more of my furnace usage components:

Heating cycle on left, fan cycle on the right

#10

Thats interesting. i’m surprised that the signatures look so different as the only difference i can think of
is the heat cycle would fire an igniter a few seconds. It does look like maybe your furnace is on
a higher speed while the burner is on and drops to a lower speed after the burners goes out. And
your fan recirculating operates at the lower speed for the duration of its cycle. I have mine set
to recirculate also but it’s determined by the thermostat for timing and sense has not detected the
fan yet.
How do you use the HS110 with it? My air handler has only 240 and is hardwired. Do they
have a 240 HS110?

#11

Sense should be able to detect it. It captured the ramp up of my AC but not the ramp down.

Captured.
Compressor spike at start up and fan(blower) slowly ramping up to 50% speed.
Fan increases to 80% speed after 1 minute after startup.
Fan increases to 100% speed after 7.5 minutes.
Ramdomly the fan drops back 80% speed which sense is able to detect but not shown in my screen shot below.
Compressor off

Not captured
Fan ramping down to 50% for 3 minutes after the compressor is OFF

What is unusual is the fan and compressor are separate units from thesame brand. Fan is an indoor air handler(gas furnace) and Compressor is an outdoor unit.

For the actual gas furnace when heating, it has only be able to capture the igniter which spikes at 105W. Same fan used for cooling above is not captured when ramping up.

#12

You also have a fan outdoors.
I have a heat pump with a similar signature and sense is not detecting anything but the compressor right now. The outdoor units compressor can fluctuate some with power use based on ambient temperature. That may be the small fluctuations your seeing. It’s hard to tell but doesn’t appear the screenshot is showing a 20% difference.

#13

That is all the usage of everything ac cooling related. It is all lumped into one device which I confirmed because my unknown (usually 200-400watts) does not change in value when the A/C comes on.

Its an ECM variable blower fan so increasing the fan from 80% to 100% add 57watts to the total.
it went from 1075watts to 1132watts for the cooling load.

edit: This the fan chart from the manufacturer. Mine is setup to run on this timer at each startup

#14

It appears that you probably have multiple stages to your compressor also. That would also explain how that waveform had an increase or a decrease. I haven’t seen where dense combines the components of something like anhear pump. For instance, my heat pump has the outdoor unit that includes a compressor and fan. My air handler (the inside half) has a fan, the 15kw heat strips and a small transformer for 24 volt control power.
So my heat pump has been detected but it’s only the compressor and not the compressor, outdoor fan and indoor fan combination even though they run together. My heat strip have also been detected individually. So when the indoor fan and heat strips run at the same time (fan slightly longer) sense only see the strips.
I had similar thoughts like yours about the system as a whole but verified it wasn’t how it was for me by unplugging thing I should t at times I shouldn’t have.
You could also be seeing just your fan

#15

It is a single stage compressor running the comfort r cooling profile on a variable gas furnace. The multiple stage units have a different fan ramp up profile where that go 25 to 40 and then 50%.

I assure you the increase and decrease is the blower fan. I have watched and listened to it closely. 1 minute after startup I hear the blower fan increase then 7.5 minutes in again like clock work that matches the sense app every time going back to summer of 2017 when it was first detected. If I manually force the cooling to dehumidify it’ll slows the blower fan to 80%. I hear it and sense shows 57-60watt reduction. Hotter days have a slight bump in consumption but the timer remains thesame.

edit. Here is the overall house consumption when the A/C came on. My place is very efficent that it easy to manually track the A/C consumption

#16

I have a similar Trane HVAC system with the Comfort-R fan profile enabled. Sense detects the cycle start based on the compressor startup, and lumps the refrigeration and fan usage together. It sees the initial fan ramp-up, but not the change 7.5 minutes into the cycle. It also misses the ramp-down after the compressor turns off. Most of the ramping visible in my usage below seems to be related to the compressor, not the fan, as the refrigerant head pressure increases. I have a two stage compressor, and the additional usage from stage 2 goes to other. I don’t see too many stage 2 calls, so Sense may never learn that. Also, defrost cycles mess things up big time, as the compressor off/on events occur at times the Sense model is not expecting, and the fan ramps up to a higher speed when it sees a W call from the compressor during defrost.

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#17

@ pswired

Here is what I did. The gas furnace install manual shows how much watts the blower should consume in cooling mode. It is listed per Ton so you’ll have to do double or triple the numbers as necessary. Mine is a 2Ton Seer 16.

My manual shows 100% blower fan speed is 280watts at 900cfm.
80% of that is 720cfm so I checked the manual. It lists 700cfm at 200 watts, so 720cfm should be just over 200 watts.

So I estimated one of these three
280watts - 210 watts = 70 watts
280watts - 215 watts = 65 watts
280watts - 220 watts = 60 watts.

Next I manually forced my cooling into dehumidify mode so the fan drops from from 100% speed to 80% speed while watching the sense app to see if how much the total consumption dropped. It varied from 57-60watts.

Once I had this number I then looked at the A/C device in sense for timed intervals increases. I also forced it to dehumidify to see if it matched the reduction.

My A/C powers on once a day and run for 6-8 hours non-stop so I made sure to test it at various times during it run cycle.

#18

You should be able to tell that way. The only difference in running cooling versus dehumidify is likely fan speed is lower. If you didn’t see fluctuations on your timeline then it’s probably the compressor and if you did then the fan.

#19

@pswired
When your heat pump goes into defrost the outdoor fan turns of and the reversing valve I operated to change to air conditioning mode.
So when you say defrost messes sense up, does sense see your heat pump compressor and fan as a single unit?

#20

Here’s the sequence of events for defrost in my system:

-Compressor and outdoor fan stop. W to air handler is energized.
-Air handler ramps up to higher fan speed to account for heat strips coming on. Incidentally, I don’t have strips, so I need to disconnect that W wire between outdoor and indoor units.
-After a few seconds to allow refrigerant pressures to equalize, the reversing valve changes over and the compressor restarts. No outdoor fan, so the startup signature looks different. Also the indoor fan is running, which is different than a usual compressor start event.
-Ice melts, then compressor stops again. Time delay. Reversing valve changes, then compressor and fan start.
-Indoor fan ramps back down to normal speed.

There’s enough difference between the compressor start at the beginning of a heat call and at the end of a defrost call (system pressures and the state of the indoor fan) that Sense doesn’t always pick up on the restart in heating mode.

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