White-rogers 1F95-391 thermostat question

[votnet]

Recently I had White-Rogers 1F95-391 thermostat installed with my Carrier central air conditioner (FV4 variable speed fan coil).

I usually set the thermostat with FAN ON option, so the fan is always running.

But sometimes, the fan stops running and word FAN in "FAN ON" on the screen is blinking. I noticed that this happens when humidity level in the room is higher than the level set in the thermostat.

In order to turn the fan on again I have to press Fan button to FAN AUTO and then again to FAN ON.

I asked White-Rogers support regarding this question and they replied that this is compressor lock-out feature. But I don't think it is, because it lasts longer than 5 minutes and it is related to FAN and not to compressor (when word "COOL" is blinking on the screen).

Anyone know what does the "FAN ON" blinking mean?

Thank you!
Alex.

[BaldLoonie]

My GUESS means that the stat knows it is humid in the house and that constant fan will put moisture from the coil back into the house, so it stops that feature to avoid raising humidity.

[votnet]

I think your guess is correct. And it helped me understand another response I just got from tech support:

"if the dehumidification set point is not satisfied, and the continuous "FAN ON" is energized, the fan "G" terminal will be de-energized with-in one second when first stage cool compressor is de-energized. The fan "G" terminal will be held off until required due to then next call for cool or the dehumidification set point is satisfied."

Now I think I understand this. It would be nice if this was explained in the manual.

Thanks!


Originally posted by BaldLoonie
My GUESS means that the stat knows it is humid in the house and that constant fan will put moisture from the coil back into the house, so it stops that feature to avoid raising humidity.

[BaldLoonie]

Good, we were right and it is a nice feature. I can't wait til they put the immense capabilities of that stat into their touch screen. And put an explanation for that feature in the manual. I went back and looked too!

[danglerb]

So what do you do to make it do what you want? Set the humidity point higher?

[votnet]

I actually thought that this was a problem with the thermostat, so I pressed the Fan button twice (FAN AUTO, FAN ON) to restart the fan.

But now, when I know that this is a feature :), I will let it work like it supposed to (e.g. stop the fan when humidity is high).

I think, if you don't want this feature, the only way around this is to set dehumidification set point higher. But in this case dehumidification function of the thermostat is useless...

[danglerb]

If I understand you right, in general you would like the humidity to be say 54% or less, but sometimes you just want the fan on and don't really care about humidity just some air circulation?

Is the fan stopping tied to finishing a dehumidification or cooling cycle for 5 min, or is it just stopping the fan independantly and forever?

Time of day programming sure makes me a LOT less happy then including some "modes" that I could setup and quickly set the system to.

[votnet]

Let's say dehumidification setpoint is set to 54%. If the humidity is less than 54% the fan will be always on.

If the humidity is more than 54%, the fan will be on until cooling cycle is complete.

When cooling cycle is complete and the humidity level is still more than 54%, the fan will shut off within one second after cooling cycle is complete, and will remain off until next cooling cycle or until humidity level will be 54% or less.

(The fan shuts off only after cooling cycle is complete.)

But if you don't care about humidity, you could increase dehumidification setpoint so the fan will be always on. Or you could restart the fan by pressing the Fan button twice.

By the way, this feature is different from the Carrier Thermidistat. With Thermidistat, the fan shuts off only for 5 minutes after cooling cycle is complete.

[danglerb]

Originally posted by votnet
By the way, this feature is different from the Carrier Thermidistat. With Thermidistat, the fan shuts off only for 5 minutes after cooling cycle is complete.


Is that due to the White Rodgers or how its wired?

[votnet]

I think, it is white-rogers' feature that is different from Thermidistat, not wiring.