Thermostatic Controls - Installed Hunter Digital Tstat, now fan pulses

I have just installed a Hunter 44860 Digital Tstat and everything seems to be working fine, both heat and cool work but I notice that my air handler fan will cycle or pulse on and off for 2-5 second intervals from time to time.

It will pulse like this after it has run a cooling cycle. The pulsing will continue for approx 5-10 minutes. I have the fan set to auto so it is not the refresh setting. It's like the fan is starting and clicks right off. During a normal heating or cooling cycle everything works fine. It is almost like the air handler has turrets!

Both outside and inside units are Trane and it is a heatpump. I have set the Tstat to heatpump and electric in the setting menu.

The Tstat is wired as such:

Old Tstat Baystat240 WeatherTron wiring - new 44860 wiring

R-RC/R
B-C
Y-Y1
Y2 not used
W-W2
X2-E
O-O
B not used
G-G
F-L

Thank you for any help you can provide.

As soon it's done cooling, remove the G wire and see what happens.

Why the change out? Was it doing the same thing with the old t-stat?

I'll try that and report back, thanks. I changed the tstat to the Hunter model so I could program the heating and cooling based on when we are at home etc. With the old mercury style tstat it worked fine without this problem just had to turn the temp up and down manually.

If pulling the g wire solves the cycling issue then what?

Thanks so far for the help.

I forgot to mention and this may have nothing to do with it but there is a Honeywell Electric air cleaner installed between the air handler and the main duct. The air cleaner does have power and appears to be working but I would have to verify how it is wired if it has anything to do with this.

I just purchased this home a month ago and the air cleaner was installed in the 70's and the air handler may be just as old.

I think the air cleaner is a F50A model.

I changed the tstat to the Hunter model so I could program the heating and cooling based on when we are at home etc.

Most of us says it's better to "Set-it-and-forget-it" on heat pump system, and sometimes on cooling.

When your system in heat mode, and your house temp has drop say 5˚ to 10˚ cooler, and now your system starts up and start heating the house, the Heat pump itself can't recover fast enough, and the t-stat is going to turn on the Aux heat (I'm guessing yours is electric) and that cost alot more money to heat vs having the HP itself keep the temp at a steady setting.

If you must have set back, you will have to upgrade to a high end t-stat that is able to "lock-out" the Aux heat.



If pulling the g wire solves the cycling issue then what?
G is what powers up the fan, I want to see if it's the t-stat that's causing the fan to do what it's doing now.

If the fan stays off with the G wire off, then it's the t-stat. FYI, when it calls again, the fan will not come on since it's not hooked up to the t-stat, so turn the switch from "Cool" to "Off" so it won't try to cool with out the fan runing.

Thanks for the quick reply. I live in Orlando Florida so during the winter months the HVAC gets turned off as heat is not needed during the winter except about 1-2 weeks in Feb and then only at night.

The main reason to install the tstat was to control the A/C as this runs up the bill during the summer. When no one is home the Tstat is set to keep the house at 82 and at 78 when we are home.

I was doing this manually at my old house and it greatly reduced the electric bill (the heat pump is electric as is most things in FL)

So with this home I figured if I can get the Tstat to do the work for me it was worth it since there were days I would forget to turn up the temp before leaving.

If the issue stops when you remove the wire, then get rid of the Hunter T-stat, and get a true t-stat like Honeywell RTH7500/RTH7600.

Hunters are good for ceiling fans only.