Humidifiers and Dehumidifiers - Honeywell TrueIAQ Digital Control giving wrong temperature & humidity readings
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MikeGIL
03-06-09, 10:13 PM
I have been dealing with low humidity in my house for what seems like forever now, and I finally took the plunge on replacing my old Aprilaire 560 to a new Honeywell Trusteam 12 gal. model HM512DG115. Actually, first I tried the Truesteam 6 gallon, but that thing ran all the time and my humidity was stuck at 30. My house is around 2,200 square feet, but I am also heating a basement so that brings it to around 3k. Anyway, I have my regular thermostat that controls the furnace, which is upstairs, set to hold at 72 degrees. The TrueIAQ digital control is mounted on the return duct in the basement, near the furnace and humidifier, but not so close that it is in a hot zone or anything like that. It is currently showing a reading of 80 degrees and humidity of 30 (I believe this reading is coming from the air inside the return, at least in theory), even though other thermostats scattered about the house show that the temp is 72% everywhere, and humidity is reading between 45-50, which is what I am looking for. I will not be satisfied that this thing is actually working right until I see some humidity on my windows. So my question is why are the readings on the TrueIAQ digital control so far off what I am seeing on all other measuring devices, and what can I do to get accurate readings from it? I called Honeywell customer service and they were completely unhelpful, just telling me to go back to my installer. My installer says it is hooked up accurately but this was the first one they have installed so he is looking into it further. Originally when it was setup it did get a reading of 72 degrees, but within a few hours that had hiked up to 82, and now it has been stable on 80. The humidity started down at 17, and now has been stable around 30 on the digital control. Also this thing NEVER GOES OFF. The guy who sold it to me said I was gonna have to walk around my house with a towel to dry off, and I wish that was the case...please help!!!!
kwsilb
03-07-09, 06:40 AM
That sounds very familiar... I replaced an Aprilaire 560 with a 12-gal TrueSteam and was very dissatisfied until I put the 560 back on as well as the TrueSteam. Of course, I later found that there was a steam leak inside the TrueSteam, near the water sensors- VERY humid air was coming out the top vents; after I moved the unit under a return duct, water was pouring off that duct. So I'm not sure how much this contributed to the weak performance.
If I were you, I would:
Check for steam leaking (is there a LOT of hot and humid air coming out the top vents? If you take out the water sensors with a Torx bit, does the gasket look OK?)
Try some better wire to the outdoor temperature sensor, although this won't affect the fact that the indoor temp always seems to read high (I've learned to just ignore that fact)
Consider putting the 560 back on in conjunction with the TrueSteam (I LOVE this setup now- I can juice up the windows in record time, then bump up the Frost Protection, and it doesn't run the TS constantly! Details at http://forum.doityourself.com/humidifiers-dehumidifiers/377633-happy-high-humidity-truesteam-flow-through-installed.html)
If I were you, I would:
Check for steam leaking (is there a LOT of hot and humid air coming out the top vents? If you take out the water sensors with a Torx bit, does the gasket look OK?)
Try some better wire to the outdoor temperature sensor, although this won't affect the fact that the indoor temp always seems to read high (I've learned to just ignore that fact)
Consider putting the 560 back on in conjunction with the TrueSteam (I LOVE this setup now- I can juice up the windows in record time, then bump up the Frost Protection, and it doesn't run the TS constantly! Details at http://forum.doityourself.com/humidifiers-dehumidifiers/377633-happy-high-humidity-truesteam-flow-through-installed.html)
MikeGIL
03-07-09, 01:03 PM
Thanks for the response...I will check to see if there seems to be humidity coming out the top. As for the water sensor, torx bit, gasket thing, I am a complete amateur, so I have no idea what you are talking about and I don't want to break this thing!
When the installer was here, we decided NOT to hookup the outside sensor, since I didn't want the thing to run based on what was going on outside, I just wanted it to go full-blast until it hit the desired humidity that I set manually (which is typically way higher than the suggested levels). Is that a bad idea? Or is that only a bad idea if running the TS along with the Aprilaire 560 at the same time? I guess I don't understand what the outside temp has to do with it at all, when really what I want is humidity to be at a certain level inside the house regardless? Pardon my lack of knowledge on this point, I would love to be educated.
I actually had already read your post, and I like the idea of running both at the same time, I wonder what my installer would think about that. Unfortunately they removed my Aprilaire 560 and now that is gone so I would have to buy a new one at this point, but I have been so flustered that I am willing to do anything to stop the sparks from occuring when I rub my dog or roll around in my blankets!!!
As for the indoor temp, I am massively OCD, and I cannot handle the thing giving me a reading of 80 when I know the air in that return is 72. It makes me feel like it is broken. I cannot believe such an advanced gadget could be so far off the mark?????
One last thing, the humidity got up to 45 inside, although the darn control still says 30, and the TS is running 24/7, but the humidity is no longer increasing, even though it is now warmer and raining outside....ugggg!!
When the installer was here, we decided NOT to hookup the outside sensor, since I didn't want the thing to run based on what was going on outside, I just wanted it to go full-blast until it hit the desired humidity that I set manually (which is typically way higher than the suggested levels). Is that a bad idea? Or is that only a bad idea if running the TS along with the Aprilaire 560 at the same time? I guess I don't understand what the outside temp has to do with it at all, when really what I want is humidity to be at a certain level inside the house regardless? Pardon my lack of knowledge on this point, I would love to be educated.
I actually had already read your post, and I like the idea of running both at the same time, I wonder what my installer would think about that. Unfortunately they removed my Aprilaire 560 and now that is gone so I would have to buy a new one at this point, but I have been so flustered that I am willing to do anything to stop the sparks from occuring when I rub my dog or roll around in my blankets!!!
As for the indoor temp, I am massively OCD, and I cannot handle the thing giving me a reading of 80 when I know the air in that return is 72. It makes me feel like it is broken. I cannot believe such an advanced gadget could be so far off the mark?????
One last thing, the humidity got up to 45 inside, although the darn control still says 30, and the TS is running 24/7, but the humidity is no longer increasing, even though it is now warmer and raining outside....ugggg!!
kwsilb
03-08-09, 07:35 AM
I'll try to explain a bit more, although I'm not a HVAC pro, just a tinkerer...
Anyway, for the torx/gasket thing, my TS was leaking through the gasket near the water sensors. If you open the top cover (unplug it first) and look on the right side near the front, there is a screw vertically with a spring wire looking thing behind it and a bunch of wires on a connector. You'll need to unplug the connector; don't forget to plug it back in or you'll get water filling errors- trust me ;). If I remember correctly, this is a "Torx" screw, which looks like an allen wrench/hex screw, but with pointy tips. If so, you'll probably need to buy a torx socket set to get in- it's bigger than Torx screwdrivers- it's a stretch of my memory, but I believe it's either T20 or T25 size. If you remove this, the wire clip swings up, and you can remove a plate with water sensors on it. I suppose these tell the machine when the water tank is full, probably when it's low also. There is a sponge gasket around the rim of this sensor plate- mine had a pinch in the corner and was letting steam out through the top of the unit, causing random errors about the voltage in the house, causing random resets, etc. If you're not having weird errors like that, and the air coming out the top does not feel tropically steamy, maybe it's not worth all that trouble.
As for humidity, I found an interesting graph for humidity at http://tc112.ashraetcs.org/programs/Denver2005_Seminar_53_Schell.pdf. On page 20, there is a graph that relates relative humidity (the "RH" curves) that you see on humidistats and hygrometers to absolute humidity (the 'Y' axis of the graph called "grains per lb of dry air") The presentation is pretty clear that the absolute humidity is what should be controlled in a house- it directly affects comfort and mold growth. Unfortunately, nearly all humidistats measure relative humidity and control the system based on that measurement. From that graph, however, you can see that it is possible to pick an upper limit for the RH that is pretty safe, as long as the temperature stays below a certain limit. For example, I never set my TrueIAQ above 45% RH, which never approaches the unsafe zone at all temperatures below 80 degrees.
Anyway, until you start seeing condensation on your windows, it is likely that an outdoor sensor is pretty irrelevant. I suspect that when you get things working the way you want, you'll need to go back and have that installed so you don't have drenched window sills on cold mornings. I imagine it would be pretty tough to convince a professional that it would be a good idea to run two humidifers like I am :eek: but I can't overstate how much happier i am now than when that thing ran constantly, blowing cold(ish) air out of all my ducts and making my electric meter spin wildly. I'm quite glad that I got the TS- the bypass unit clearly couldn't keep things as humid as I wanted them in the winter...
Anyway, I'm a bit pessimistic generally about the TS ratings, but I wish you luck getting it to work without running 24/7. As for humidity readings around the house, I think that the TrueIAQ is pretty good with humidity readings (probably better than most cheap digital hygrometers) and I think you can believe what it is saying as long as the installer used the duct-mounting adapter (a little probe that pokes through into the duct if I remember) But I don't believe the temperature readings it comes up with. If I were to guess, I'd say that it gets hot in operation, and this throws off it's temperature readings by up to 10 degrees! If I cared more, maybe I'd blow a fan on the unit and see if it's temperature approaches the temps in the rest of the house? But my thermostat is nearby, and I really just use that for temps, and the humidistat for humidity. And the relative comparison between outdoor temp and humidity is all that is important for good condensation protection- I think that factors into why I have to set the Frost Protection parameter so low (3!) to keep window condensation away.
I hope this helps...
Anyway, for the torx/gasket thing, my TS was leaking through the gasket near the water sensors. If you open the top cover (unplug it first) and look on the right side near the front, there is a screw vertically with a spring wire looking thing behind it and a bunch of wires on a connector. You'll need to unplug the connector; don't forget to plug it back in or you'll get water filling errors- trust me ;). If I remember correctly, this is a "Torx" screw, which looks like an allen wrench/hex screw, but with pointy tips. If so, you'll probably need to buy a torx socket set to get in- it's bigger than Torx screwdrivers- it's a stretch of my memory, but I believe it's either T20 or T25 size. If you remove this, the wire clip swings up, and you can remove a plate with water sensors on it. I suppose these tell the machine when the water tank is full, probably when it's low also. There is a sponge gasket around the rim of this sensor plate- mine had a pinch in the corner and was letting steam out through the top of the unit, causing random errors about the voltage in the house, causing random resets, etc. If you're not having weird errors like that, and the air coming out the top does not feel tropically steamy, maybe it's not worth all that trouble.
As for humidity, I found an interesting graph for humidity at http://tc112.ashraetcs.org/programs/Denver2005_Seminar_53_Schell.pdf. On page 20, there is a graph that relates relative humidity (the "RH" curves) that you see on humidistats and hygrometers to absolute humidity (the 'Y' axis of the graph called "grains per lb of dry air") The presentation is pretty clear that the absolute humidity is what should be controlled in a house- it directly affects comfort and mold growth. Unfortunately, nearly all humidistats measure relative humidity and control the system based on that measurement. From that graph, however, you can see that it is possible to pick an upper limit for the RH that is pretty safe, as long as the temperature stays below a certain limit. For example, I never set my TrueIAQ above 45% RH, which never approaches the unsafe zone at all temperatures below 80 degrees.
Anyway, until you start seeing condensation on your windows, it is likely that an outdoor sensor is pretty irrelevant. I suspect that when you get things working the way you want, you'll need to go back and have that installed so you don't have drenched window sills on cold mornings. I imagine it would be pretty tough to convince a professional that it would be a good idea to run two humidifers like I am :eek: but I can't overstate how much happier i am now than when that thing ran constantly, blowing cold(ish) air out of all my ducts and making my electric meter spin wildly. I'm quite glad that I got the TS- the bypass unit clearly couldn't keep things as humid as I wanted them in the winter...
Anyway, I'm a bit pessimistic generally about the TS ratings, but I wish you luck getting it to work without running 24/7. As for humidity readings around the house, I think that the TrueIAQ is pretty good with humidity readings (probably better than most cheap digital hygrometers) and I think you can believe what it is saying as long as the installer used the duct-mounting adapter (a little probe that pokes through into the duct if I remember) But I don't believe the temperature readings it comes up with. If I were to guess, I'd say that it gets hot in operation, and this throws off it's temperature readings by up to 10 degrees! If I cared more, maybe I'd blow a fan on the unit and see if it's temperature approaches the temps in the rest of the house? But my thermostat is nearby, and I really just use that for temps, and the humidistat for humidity. And the relative comparison between outdoor temp and humidity is all that is important for good condensation protection- I think that factors into why I have to set the Frost Protection parameter so low (3!) to keep window condensation away.
I hope this helps...