Heat Pump Fan Running w/ Furnace

[kkjellquist]

Hey y'all we have a 12ft Flagstaff A Frame w/ a heat pump (heat & AC) and a traditional furnace. We really needed the furnace heat for the first time this past weekend and I noticed something odd.

When the furnace is operating it cycles on and off as needed to maintain the proper temp. However, the fan from the heat pump is running at all times and blowing cool(ish) air.

Is this operating properly?

[Flybob]

Your thermostat has a heat/cool/auto setting as well as a Fan Hi/Lo/Auto setting. Make sure the Fan setting is set to Auto. On Hi or Low the the fan will run whenever the furnace is running. The idea is it helps circulate the air.

[kkjellquist]

Many thanks!

[sundancer330]

No thats not right, this is what happens when non a framers answer. The domestic tstat is designed to only allow the a/c-heat pump or the furnace to run by themselves. If I run my propane furnace the a/c-heat pump is not running the fan, something is messed up with your wiring at the tstat.

[T11ravis]

Originally Posted by sundancer330

No thats not right, this is what happens when non a framers answer. The domestic tstat is designed to only allow the a/c-heat pump or the furnace to run by themselves. If I run my propane furnace the a/c-heat pump is not running the fan, something is messed up with your wiring at the tstat.

Well there must be a lot of "messed up" tstats out there as that is exactly what mine does as well as 1 of my friends who owns the same unit.
Put the fan on auto and it magically shuts off.

[Scrapper]

kkjellquist, what is the make, year and model number for your A-frame and a/c heat pump along with the furnace. Do you have the owners manual and other documents that came with the a-frame. If you get the make and model numbers you can get the necessary documents online.

[sundancer330]

Originally Posted by T11ravis

Well there must be a lot of "messed up" tstats out there as that is exactly what mine does as well as 1 of my friends who owns the same unit.
Put the fan on auto and it magically shuts off.

A regular tstat yes it will work that way. The Dometic led tstat only allows it to be in one setting at a time, you can't turn on the furnace and the heat pump-a/c fan together. Here is what it looks like. Once again the non aframers don't have any idea whats in these units.

[Mr. Dan]

Originally Posted by sundancer330

A regular tstat yes it will work that way. The Dometic led tstat only allows it to be in one setting at a time, you can't turn on the furnace and the heat pump-a/c fan together. Here is what it looks like. Once again the non aframers don't have any idea whats in these units.

I'm almost willing to bet a Reese's Pieces that if you click the Mode button on the pictured thermostat until the FAN light comes on, you can click the + or - button, you can cycle through FAN settings of HI, LO, and AU (for Auto). The AU setting on my almost exactly same (except for color) DOMETIC thermostat will prevent the fan from running while the furnace is on.

[Scrapper]

kkjellquist & sundancer330

There has been several threads on that thermostat. If I recall, it does have a auto setting for the fan and you have to use the On/Off Mode button in combination with the +/- buttons.

The latest thread was yesterday if I remember right.

edit: X2 what Mr. Dan said.

[Flybob]

https://www.manualslib.com/manual/72...c-3313192.html

[T11ravis]

Originally Posted by sundancer330

A regular tstat yes it will work that way. The Dometic led tstat only allows it to be in one setting at a time, you can't turn on the furnace and the heat pump-a/c fan together. Here is what it looks like. Once again the non aframers don't have any idea whats in these units.

Boy that sure looks familiar...

[Scrapper]

sundancer330, you know that thermostat is not only used with a-frames, nor with only the Cool-Cat a/c heat pump?

[FrayAdjacent]

I'm a new owner of a 2015 194HW, and can verify that the 'stat, when put into fan only mode, will allow you to switch between Hi, Lo and Au(to).

I don't know what those settings do in relation to the furnace, as I have not tried starting the furnace. I have run the Cool Cat on both heat and cool modes, and it works fine.

[withoutoneplea]

What's an a-framer?

[Mr. Dan]

Originally Posted by withoutoneplea

What's an a-framer?

Apparently, it's a person who owns/operates/knows about an A-Frame camper.

[bubbles]

Originally Posted by FrayAdjacent

I'm a new owner of a 2015 194HW, and can verify that the 'stat, when put into fan only mode, will allow you to switch between Hi, Lo and Au(to).

I don't know what those settings do in relation to the furnace, as I have not tried starting the furnace. I have run the Cool Cat on both heat and cool modes, and it works fine.

That TS will not allow furnace fan control (don't know if any rv TS will) but will allow AC and FAN mode control. Typically the furnace is a stand alone and its fan controls the sail switch for combustion to begin. The TS furnace select interconnect does go through the AC and that is why the AC fan will also run if the TS FAN mode is not set to AU. Heat strip/heat pump modes same as AC.

[Jaydubya81]

The furnace is completely separate
From the coolcat. The coolcat in heat or AC has three settings : low, high and auto. When running the coolcat I prefer to use either high or low fan settings vs Auto, because I can’t sleep when something is constantly turning on and off, so I hardly ever use auto. The furnace fan has one speed ,on or off . Hope this helps, I have the exact year and model you have, it seems to me that the 194hw is fairly uncommon, my wife loves the shower/cassette, no more finding shoes and a flashlight to go the restroom in the middle of the night’

[handbuilder]

If you don't want the fan blowing cool air (not AC air) while the furnace is operating, you must be in the "Auto" mode. Using the +/- to change settings and set your temp.

Do a search in the A-Frame forum, you'll see several threads on this very question. Aside from the furnace causing alarms the first time it is used, this seems to be part of new owner hazing. Hahah

[mickrock]

a completely separate unit from the Coolcat.

However, and just to be aware of, the two thermostat wires for the
lp furnace come from the Coolcat unit.

So, there is some interaction for thermostat control purposes.

[MontyPP]

My Cool at comes on prior to the furnace kicking on with its own fan. There is no fan control for either. It is constant low blow. I have a 2017 T21TBHW.