[cdodge]

Hello,
I just bought an ecobee3 thermostat for my condo that I am renting. It previously had a Venstar T2800 Thermostat.
I have a FHP Bosch EC024- Unit, and I believe it’s a geothermal since there is water connections going in and out and that’s seems to be what I found after doing some research. I know it is a Heat Pump from the settings off of the old thermostat.
The Venstar T2800 has the humidity chip installed and had a wire going to the MISC2 port. There is a jumper on the thermostat that allows you to pick what you have hooked up Hum, DeHum, etc. The jumper is currently on Dehum so I am pretty sure there is a built in dehum into the FHP system. I connected that wire to the misc port on the ecobee and selected dehum.
The issue I am having is any time the fan runs the humidity goes up quickly. If I turn just the fan on when humidity is 52 it will jump up to 70 within 10 to 15 minutes. I have the option to run the fan when the dehumidifier if running and since the fan is running the humidity actually goes up.
Does anyone know why running the fan would cause the humidity to go up that quickly?
I live in South Florida and my condo is on the 16th floor facing north if that helps at all.

 

[beenthere]

Probably doesn't have a built in dehumidifier like you think. It may have a hot gas reheat coil. Which when activated while the A/C is running will dehumidify without over cooling the place, because it is reheating the air.

Good chance that your re-evporating the water off the coil with the Ecobee3 thinking its running a real dehumidifier.

 

[SeniorSitizen]

Try taking a real Hum reading as far away from the stat as possible. You may find DeHum isn't needed at all.

 

[cdodge]

Try taking a real Hum reading as far away from the stat as possible. You may find DeHum isn't needed at all.

Thanks for the response. I turned off the dehum in the options on the ecobee for testing and the issue is still there.

I don't think the issue is with the dehum or the AC, it's strictly with the fan running. I turned everything off except for the fan and the humidity still goes up quickly.

 

[SeniorSitizen]

Thanks for the response. I turned off the dehum in the options on the ecobee for testing and the issue is still there.

I don't think the issue is with the dehum or the AC, it's strictly with the fan running. I turned everything off except for the fan and the humidity still goes up quickly.

I take it you are still reading the Hum from the stat?

 

[cdodge]

I take it you are still reading the Hum from the stat?

yes, I don't have any other tools that read the hum.

Thanks!

 

[SeniorSitizen]

For starters take a look see what the National Weather Service says the outdoor Hum is nearest you by entering your zip in upper left. Unless there is indoor activity such as boiling water or hot steamy showers the indoor and outdoor R H usually aren't far apart.

http://forecast.weather.gov/MapClick.php?lat=37.8829&lon=-76.3459#.Vtd8uebrqtE

 

[cdodge]

For starters take a look see what the National Weather Service says the outdoor Hum is nearest you by entering your zip in upper left. Unless there is indoor activity such as boiling water or hot steamy showers the indoor and outdoor R H usually aren't far apart.

http://forecast.weather.gov/MapClick.php?lat=37.8829&lon=-76.3459#.Vtd8uebrqtE

Thanks for the replies I really do appreciate all the help.

Earlier today when I checked the outdoor humidity it was 55, which is what my thermostat originally reported. Once I turned the fan on it jumped to 70 within 5 to 10 minutes. I am wondering if there is something wrong with the ecobee. Does it make sense that just turning on the fan only would cause the humidity to increase that fast? I always thought the fan circulated air which lowered humidity.

 

[beenthere]

Thanks for the replies I really do appreciate all the help.

Earlier today when I checked the outdoor humidity it was 55, which is what my thermostat originally reported. Once I turned the fan on it jumped to 70 within 5 to 10 minutes. I am wondering if there is something wrong with the ecobee. Does it make sense that just turning on the fan only would cause the humidity to increase that fast? I always thought the fan circulated air which lowered humidity.

Just circulating air, doesn't lower humidity. Your system may have a fresh air intake. Which means its pulling in that humid air. And when the A/C runs to keep the temp down, it doesn't run long enough to remove the humidity.

 

[MrWigg]

CDODGE you are confusing humidity with relative humidity. The two terms aren't interchangeable and can lead to confusion. Once you get that figured out your problems will be over.

 

[cdodge]

CDODGE you are confusing humidity with relative humidity. The two terms aren't interchangeable and can lead to confusion. Once you get that figured out your problems will be over.

you could be right. I saw some posts on the differences but didn't read up to much on it.

Would running the fan still cause RH to go up? This did not happen with my old thermostat. The issue is when I go to bed at night I have the temp set to 70 degrees. The AC and fan run more to get to that temp so it causes the RH to go up. I have the RH set to 60 on the thermostat but the actual RH goes up to 70 causes the dehum to run to try to lower it to below 60. The dehum uses the fan and the fan raises the RH so it seems to be fighting each other.

 

[SeniorSitizen]

Using the link below, set the temperature scale on 70°F, click on solve for RH and while running the dew point scale up in the 60-70 degree area watch the preservation evaluation change. Maybe you can tell us why you would want the RH that high when 40 % RH is a reasonable number.

http://dpcalc.org/

 

[beenthere]

Your heat pump doesn't have a dehumidifier built into it. It may have hot gas reheat. Which means the A/C must run at the same time its trying to dehumidify. You told the Ecobee you have a dehumidifier, and to run the fan at the same time. Since you don't have a dehumidifier. Only the fan is running, and your humidity is rising. The Ecobee has to be told to over cool to dehumidify. It may be able to be told to bring on the hot gas reheat. If not, then tell it to slow the blower by energizing the terminal you already have connected that you thought was a dehumidifier.

In case you don't have hot gas reheat. Post a pic of your heat pump and its ducts. Are you sure you don't have a humidifier.

 

[supers05]

Apparently those models had an economizer option also. With the fan on, and the damper stuck open, or something miswired, you'll get lots of humid air being sucked in.

Ref. = http://www.geoexcel.com/fckuploads/file/EC Specs & Install.pdf

Please post a picture of the unit, including inside if it's possible.


Cheers!

 

[beenthere]

That link will tell you about tjhe hot gas reheat for dehumidification.

 

[cdodge]

Apparently those models had an economizer option also. With the fan on, and the damper stuck open, or something miswired, you'll get lots of humid air being sucked in.

Ref. = http://www.geoexcel.com/fckuploads/file/EC Specs & Install.pdf

Please post a picture of the unit, including inside if it's possible.


Cheers!

I attached photos. I hope they get attached ok

 

[cdodge]

pics of old Venstar T2800 wiring and jumper positions

 

[cdodge]

pic of ecobee wiring

 

[beenthere]

Is the Ecobee set up to cool to dehumidify? If not, there is 1 of your problems.

 

[cdodge]

Is the Ecobee set up to cool to dehumidify? If not, there is 1 of your problems.

I could not find that option but there is an option to run fan when dehumidify.

Even if I turn of dehumidy option complety, any time I run the fan the RH shoots up to 70. So any time the AC runs or the dehum the RH goes up.