TrueIAQ Temperature Differential


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Old 01-15-11, 12:47 PM
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TrueIAQ Temperature Differential

I recently installed a TrueSteam and a TrueIAQ w/ outdoor sensor (module not rtd). The TrueIAQ is controlling the TrueSteam and the Truesteam is operating the fan correctly. The only problem is a 10 degree differential with the outdoor temperature (confirmed when comparing to two other temperature devices). The outdoor sensor is wired using 18/2 tstat wire <25 ft and not ran with 120VAC. The TrueIAQ just does not seem to adjust to outdoor conditions. The "frost protection" setting is enabled and I have set it to various values and I have seen no change in the control setpoint. The humidity setpoint always remains at the manual value I set (usually 30 or 35). Essentially the things is working like a manual humidistat. I have seen threads on here with the same or similar problems with no resolution or conclusion. Honeywell declined to help because I am not a contractor.
 
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Old 01-15-11, 04:47 PM
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you can always try running the outdoor stat wire in shielded wiring...
 
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Old 01-15-11, 07:35 PM
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thanks hvactechfw. if replacing the unit doesn't work then i will try twisted pair. are you familiar with the trueiaq? how does it adjust for outside conditions? should i see the setpoint change automatically when i have frost protection enabled? whats the secret to get this thing to respond to outdoor conditons?
 
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Old 01-15-11, 07:48 PM
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the idea behind frost protection is fo rit to do what it does which is keep condensation off windows. set you rh @ 45% and start out on 9 for frost protection. let humidity level get achieved. if you have frost then lower frost protection. it actually works the opposite of what you would think it should work. the main thing I can tell you is to read your manual. the set point does not change from what you have it set at. at least it doesn't show a different setting then what you have set. depending on the outdoor temp and your frost protection level it will compensate to call or not call for humidity based on it calculations to ensure you don't get condensation on your windows.
 
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Old 01-15-11, 08:02 PM
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thanks for your help. i appreciate it
 
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Old 01-22-11, 05:54 AM
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Today -2 outside, truiaq reads 5. Frost setting is 6 (I've adjusted this down), I set hum to 30% before going to bed. This morning frost everywhere. Hum reaches setpoint it quits calling for humidity. The humidity decreases 2% and the unit calls for humidity until setpoint is reached. This unit isn't regulating humidity based on outdoor settings. It just maintains the manual setpoint I enter. I've monitored this over periods of days. Driving me crazy.
 
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Old 01-22-11, 06:09 AM
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the lower the number of frost setting the more it will compensate. mine is on 2 to keep frost off the windows. but it cant remove humidity! If it got really cold over night, colder than it had been then it can't compensate for a drastic change like that because it cant remove moisture from your home. If i set mine on frost protection 6 it will frost windows at 20 degrees. THE LOWER THE NUMBER, THE BETTER THE FROST PROTECTION
 
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Old 01-22-11, 06:26 AM
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Agree, the problem is that the unit continues to introduce moisture. My house is only 5 years old and is well insulated...pretty tight. The setpoint is 30 and that is what it tried to maintain. Based on the manual it should adjust to provide less humidity with an outdoor temperature. I have not witnessed any time in which the unit did not perform a humidity call when humidity is SP-2%. Also, should the "window frost" indicator come on when it is NOT calling for humidity based on outdoor conditions? My friend has an aprilaire controller and it automatically adjusts is humidity level down when the conditions are colder, shouldn't the IAQ do the same?
 
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Old 01-22-11, 06:38 AM
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i set WF to 3, WF indicator came on. I will monitor the performance over the next coupe of days...thanks for your help.
 
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Old 01-22-11, 06:48 AM
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IT DOES!!!!!! SET YOU FROST PROTECTION TO 2! mine is set for 45% actual RH in house is 36% @ 12 odt. Furnace is running and humidifier is not running even though the setpoint is higher then the current RH in the house. 4 year old house built tight with heat pump system with gas backup.

Side note.

Part of your problem could be the fact you have a trusteam. I don't like those. They are nothing but problematic. Steam units create a lot of mositure very quickly. Honestly it sounds like you are adding too much moisture too quickly. Is your truiaq duct mounted or living space mounted? I am also an advocate for NOT duct mounting a humidistat. They are NOWHERE close to being as accurate as being mounted in the living space. Also your humidifier should be setup to only run with the furnace and not be able to turn the furnace fan on with a call for humidity.
 
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Old 01-22-11, 07:09 AM
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Its frost protecting now with the lower setting. not sure who could ever use 9 for this setting.... The truesteam seems to be working well. The humidistat is duct mounted; however, I adjusted a +5% offset(the unit was reading low humidity) which makes it consistent with a humiditiy sensor I have upstairs. btw, how should t he duct sensor be aligned with air flow? the manual is vague. I have the sensor rotated so that the two holes in the sensor tip are vertical, air fow is vertical as well.

I've read several threads regarding how the unit should be configured. As it is now, the truesteam controls the fan. I was thinking of wiring the humidistat to control the fan but it is powered by the truesteam and unless the truesteam 24vac and the furnace 24vac share a common i was thinking i'd have to power the humidistat from the furnace. I wasnt going to deal with that until i got a new IAQ which hopefully reads a more accurate outdoor temperature.
 
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Old 01-22-11, 07:13 AM
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correction, i wanted to wire iaq to monitor call for heat....W terminal. But I am not sure the furnace and 24vac output from truesteam which powers iaq share the same common.
 
 

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