Dometic Thermostat?

[chuckstovall]

Hi.  Hull #297, 2017 LEII.   This may well be operator error, but sometimes when I turn on the furnace i get just the furnace.  Nice!  But other times when I turn on the furnace, I get the furnace as well as the A/C.  When the A/C comes on, it blows cold.  

This particular trip, I had used the furnace exclusively with good results.  Then the other day, I ran the A/C in the afternoon.  The next morning, I believe is when turning on the furnace also started up the A/C.   Note: I do see that when selecting heat on the thermostat, I can chose 'heatstrip' or 'furnace' and am specifically choosing 'furnace'.  

BTW - I'm happy with the furnace when I get it only.  Mine is quiet enough for this old guy who is HOH.  Not so happy with the A/C.  Besides the loudness, it doesn't do a great job of cooling the space off.  I say these last two points not to start a dialog one furnace or A/C; those have been done.

Thanks in advance for any input you may have.

[katanapilot]

If it's the Dometic CT thermostat, you need to choose "Auto" for the fan speed, otherwise the A/C fan will run in either low or high as selected.  I think the owners manual for the thermostat talks about this.

[Frank C]

Sounds like you may be inadvertently turning the air conditioner fan on as you’re scrolling through thermostat settings.  There are fan settings for low and high and “auto”.   You want “auto” mode.  

Edited March 6, 2021 by FrankC

[chuckstovall]

6 minutes ago, katanapilot said:

If it's the Dometic CT thermostat, you need to choose "Auto" for the fan speed, otherwise the A/C fan will run in either low or high as selected.  I think the owners manual for the thermostat talks about this.

I think that was it.  Thanks.  

[chuckstovall]

6 minutes ago, FrankC said:

Sounds like you may be inadvertently turning the air conditioner fan on as you’re scrolling through thermostat settings.  There are fan settings for “on” and “auto”.  

Thanks FrankC.  That did it!

[SeaDawg]

@chuckstovall, don't feel bad. I wish I had a dollar for every post (on this forum and others) about the dometic thermostat. Makes me glad for our less sophisticated analog furnace thermostat, and button controls on the ac, in our 2008.

[chuckstovall]

5 hours ago, SeaDawg said:

@chuckstovall, don't feel bad. I wish I had a dollar for every post (on this forum and others) about the dometic thermostat. Makes me glad for our less sophisticated analog furnace thermostat, and button controls on the ac, in our 2008.

Wanna trade?  🙂

[thompsonkd]

I am not sure where to post this; couldn’t get the search feature to pull up the right thread. We have the Dometic furnace- works good with the exception of the sail switch frequently collecting bits of hair (we are traveling with a cat) and lint and consequently not allowing the unit to ignite until we take the switch out and clean it off.  As noted, the unit works well when it runs. I am wondering if anyone else. has encountered this issue and what they do about it. I thought of putting a foam filter over the intake but worried about impeding air flow; apparently Dometic does not recommend filters for the unit. Thanks. 

[John E Davies]

41 minutes ago, thompsonkd said:

I am not sure where to post this; couldn’t get the search feature to pull up the right thread. We have the Dometic furnace- works good with the exception of the sail switch frequently collecting bits of hair (we are traveling with a cat) and lint and consequently not allowing the unit to ignite until we take the switch out and clean it off.  As noted, the unit works well when it runs. I am wondering if anyone else. has encountered this issue and what they do about it. I thought of putting a foam filter over the intake but worried about impeding air flow; apparently Dometic does not recommend filters for the unit. Thanks. 

I think that a coarse furnace filter, changed seasonally, would be fine. Big enough holes to let through lots of air, but still able to catch hair and dust bunnies. I’m not 100% sure about the hair getting to the sail switch,  isn't that inside the combustion area, like in my Suburban? Or does Dometic have an additional one for the cabin air...?

John Davies

Spokane WA