High low fan on forced air help please

[rombi]

Our Aquatherm feeds our house with a HX in the forced air furnace. I just noticed after about 5 years of use that I don't remember the "high" fan ever kicking in with the boiler thermostat that is mounted above our propane thermostat. With the propane when it needs to use the high fan it works but not with the wood thermostat. Before I call an electrician friend of mine I was just curious if this is possible or is it my cheapo thermostat that I have for the wood? It works but I think the high fan would be better for pumping the heat from the basement to our 3rd and 4th floors of our house. To me I would rather have it wired to high all the time.

 

[RobC]

I know my air handler you have to change the wire leads inside the air handler control box. You pick high, med or low and wire nut the leads together. So, thermostat just calls for run cycle and either hot or cold but not fan speed.
You might want to add the 2 thermostats your running and the make of the air handler to your post.

 

[rwh442]

I have a variable speed blower in my propane furnace - so this may not apply to your situation.

The way I achieved a high fan speed was to use my air conditioning circuit. I disconnected the compressor wiring with a "Boiler/AC" toggle switch I added - dependent upon season.

 

[rombi]

Still looking at this, I think we are going with the switch idea, hate to fry the motherboard.

 

[rkusek]

Does it not keep up on low? Mine is not variable just has the 3 or 4 settings like RobC says that must be hardwired. I swapped mine to the low setting although it doesn't seem that much different less. House always within 1 degree of setpoint and comfortable. I'm not a big fan of the blast furnace type heating (hot, cold, hot, cold) that we had with the high eff. gas furnace in our old house. Seems like it dried out our noses & throats too much also. Every room in that house had to have a humidifier and we still had issues. The Aprilaire humdifier on the air handler in the new house is awesome. If you're not using storage a low setting running longer may be better on the boiler too.

 

[rombi]

It is great on the first floor. We have our garage/basement where the furnace lives then three heated stories on top of that. With it running on low the upstairs and the way upstairs don't get more than a wiff of heat. It just rose to 3 degrees here at 1:50, nice and cold but our house is doing fine, just a little cold upstairs. I am fine with it but the ladies in the house rule the thermostat.

 

[RobC]

On the Main Trunk feeding the smaller ducts that go to rooms, do you have dampers that you could close just a bit for the first floor ? This will push more air to upper stories.
Inversely, before you adjust the above, take inventory of all dampers to make sure the ones going to the upper floors are not closed off.
The other place you may find a damper is, if you reach down the emitter in the room(s) they will be right there.
If no dampers you may need to wire to medium instead of low.
Air filter clean at air handler ?

 

[rombi]

Yes I put a new filter in and we have dampers that I have played with. I like not hearing the blower run but I think it is time to ramp it up a bit to move some air. It is a newer Carrier furnace and even on high there is little noise in the furnace room but you can hear it spinning. If only I could have started from scratch and built the house the way I would like to.

 

[RobC]

Newer & ramp it up a bit.... Do you have an automatic variable speed fan motor ? Can't remember all details about what the motor "looks at" to determine speed selection but that may be the issue.
If you don't have the manual see if you can get it online from Carrier.