Any HVAC pros out there?

3 years ago

AC Fan help..

I used to have an old school dial thermostat. You'd flip a plastic switch that went from heat to central air. Flipping that switch turned off the central air completely, no fan, no AC, nothing.

Fast forward to this year, we had some work done and the guy replaced the thermostat with a digital one. He’s since become unavailable.

When I turned the heat on this year, the Central air fan starts blowing. The whole house feels much colder then in years past.

I checked the settings on the thermostat and there is nothing that allows me to turn the fan completely off.

Fan options are: On, Circ or Auto.

My question is,

Is this right?

Should I turn the central air unit in the attic off with the main switch to override the fan and shut it all down?

IDC that it's on, but I worry that it's going to burn out the system or that’s it’s causing the house to be colder.

Heat is oil heat through baseboards.

Central air ducts are in the ceilings.

Thanks in advance!

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Comments (12)

PRO
Big Roots Consulting
3 years ago
Turn the fan to Auto and choose your temperature.
Bill H
3 years ago
last modified: 3 years ago
On: fan will run all the time. Circ: fan will run a certain percentage (usually 35% of each hour or whatever % its set for). Auto: fan will only run when unit is cooling. So the closest option you have to ”off” is ”auto” since the fan won’t run unless its cooling.
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A Mat
3 years ago
Often, the instruction manual is avaiable on the internet.
wdccruise
3 years ago
"Heat is oil heat through baseboards."

The thermostat was not configured correctly. The thermostat wasn't configured for baseboard/radiant heat so it incorrectly sends power to the AC blower even when it calls for heat. The blower should only be turned on when the thermostat calls for cooling.

"Fan options are: On, Circ or Auto."

You should leave it on Auto. But Auto should send power to the fan only when the thermostat calls for cooling, not heat. This error is a result of the mis-configuration of the thermostat.

What is the brand and model of the thermostat? Do you have the installation instructions?
wjab
Original Author
3 years ago
This is a picture but I don’t have the instruction booklet.
wjab
Original Author
3 years ago
There is a light switch in the attic that will override the fan should I do that until I can have someone come in to reconfigure it?
PRO
Charles Ross Homes
3 years ago
It's not clear whether you have an air cleaning system or a steam humidifier installed in your duct work, but if so, you'll want to maintain the option to run the fan in circulating mode in order to utilize them.
wjab
Original Author
3 years ago
Thanks all! I’ve set a service call next week to get this sorted out. I appreciate the feedback.
Stax
3 years ago
If the OP can not find the Model Number for the thermostat, she'll never find the manual on line and will thus have to pay for a tech to come and likely sell her a new device.
Stax
3 years ago
last modified: 3 years ago
Try Honeywell RTH8560D

Manual
wdccruise
3 years ago
last modified: 3 years ago
Here's the Honeywell RTH8560D 7 Day Programmable Touchscreen Thermostat - Use Manual(link from Stax, above)
1. Open the website above.
2. Click the link in the table of Contents, System Setup Options
On the thermostat:
1. Press and hold MENU for 5 seconds. Press < and > to scroll through options.
2. Press > until you see option 200; set Options to "3 = Radiant Heat (Boiler)"
3. Press > until you see option 205; set Options to "9 = Hot Water Radiant Heat"
4. Press > until you see option 300; set Options to "0 = Manual"
5. Press > repeatedly until you have cycled through all of the System Setup numbers, Done is displayed. Press Select to save and exit.
wjab
Original Author
3 years ago
https://manualsfile.com/product/wy2k5yhrq.html

After a little more searching on the thermostat I found this was the model. I found the manual online followed the instructions and it worked!

Thank you everyone! I’m very grateful for all the guidance and saving me (hopefully) a service call.

Happy Holidays!