How To Operate A Dometic Single Zone (SZ1) RV Thermostat

[@rebeccaphelps6878]

Oh my gosh thanks for this video. I got home on a cold night, turned my furnace on and the A/C started running too. I was freaking out, frantically looking through all the owner manual info and of course it is no help. Pulled up this video and fixed the problem in 30 seconds and also learned about my thermostat. You made this old lady and her dog very happy and gave me a sense of accomplishment!!

[@brendarichardson7271]

*Works great **Fastly.Cool** compact and Easy to install*

[@Tryke_Ryder]

I have this exact thermostat and I never had anyone explain it better! Actually, no one EVER explained it! Thank you!!

[@dennisdoucette9373]

BINGO, I GOT THE RESULTS I WANTED ABOUT 5 MINUTES INTO THE VIDEO! OBVIOUSLY I WATCH THE ENTIRE SHOW. FABULOUS EXPLANATION. THANKS SO MUCH👍

[@ralphiemcginn2479]

i could not have asked for a better explination ! ive had my camper for 5 years and suffered with that stupid fan running with the furnace ! i figured it was made to run that way until this weekend i got fed up of freezing my toes ! thank you thank you thank you!!!!!!!

[@boss-tech8513]

What's the purpose of having the fan on when the furnace is on?

[@free2roam492]

Wow! Best explanation. We just returned from a week long trip and thought there was something wrong with our dometic thermostat. We did not have internet so glad I waited until we got home before making a service call. I guess it turns out we needed to watch your video and understand the thermostat. Thanks for saving us $$$$$$$$. Cheers!

[@jos1062]

Thank you so much! No one ever explained the thermostat to us either and I guess we thought it worked like our home. So easy to understand now that I have seen it. One more thing I would like to add that happened to us - we had a roof vent shooting cold air directly at the thermostat which caused the a/c to turn off and then turn right back on once it realized it wasn't really as cold as the temp set. When we closed that vent, the a/c turned on and off (on auto) as it should, reached the desired temp and shut off. The vent was actually installed aimed at the thermostat and is not one of those that you can change direction. My husband switched it with another so it's not aiming at the thermostat. The dealer kept telling us we were running both furnace and a/c at the same time and that was causing the problem but they were completely wrong. Your video should be shared with all first time RV buyers. Would save lots of aggravation. Again, a big thanks!

[@chuckmerkins1631]

I've had this thermostat for 5 years and I didn't have a clue of these details...Thank you

[@jos1062]

Same as us, 5 yrs of hit and miss and here we are, now understanding perfectly.

[@janefletcher3198]

What a life saver we are camping it is cold at night . We thought both air and furnace was coming on. I had searched and couldn’t find anything . We have no books when we bought the motor home I have one I downloaded but the 2 thermostats it shows are not this one. Thank you so much I will save this video

[@xandefabia]

What a great explanation!! No one at the dealership where I bought my RV has explained that to me. Thank you!!!

[@LordFalconsword]

I have my doubts if they understood it either.

[@daryllect6659]

@@LordFalconsword I'm absolutely *_sure_* my dealer doesn't! These Dometic thermostats are unpredictable, unreliable, overly-complicated, difficult to use pieces of total crap..

[@jimdidonato1246]

This is a great video. My Coachmen Freedom Express RV has this thermostat, and (until now) it's been a mystery to me how to set the thermostat in the heat mode. Now I know!! Well done, My RV Works! Thanks!

[@butterfly1948]

Thank you! Thank you! Thank you! I thought the AC and furnace was on at the same time. The fan is so loud. Now I can sleep. This information is so helpful.

[@274Brian]

Best explanation I've seen about these single zone units! THANK YOU SO MUCH!

[@Deltatango210]

On a campsite now with a new trailer, A/C was driving us nuts, this video cured the problem, awesome, thanks!!!

[@SedroWoolley100]

Thank you for taking the time to create that video and for explaining that system so well! It's exactly what I was looking for.

[@RTegeder]

An easy-to-understand explanation eliminating the mysteries of this thermostat. The first time I used it on a cold morning, it was very disconcerting to have my ceiling fan blasting out/recirculating the cold air. Knowledge is power! Thanks!

[@sandyphillips5194]

Wow! You are amazing. I thought I had an issue with my AC and it was stressing me out! I was on with my Facebook groups, which by the way are wonderful but couldn't find the answer as to why my ac would shut off for a second or two and the compressor would buzz while it was off. I'm a visual person so this is great. Your explanation of all your videos is great. And also didn't know about the furnace and fan so I learned so much watching your video. Thank you!

[@jc525exc]

Thanks for clearing this up. My Fan was coming on up top with my heater on. I called dealer & manufacturer of my unit and they told me I must have a crossed wire, that should never happen??? They told me to shut off my A/C fan at circuit panel to resolve problem. I also asked how to put A/C fan on low? They both told me it only runs on high. You understand it, they need to watch your video.

[@billandjanlloyd5252]

Same thing my dealer told me!!

[@chilzky14]

Thank you so much for this video i just bought an rv And couldn't figure out why my fan wasn't turning off.. life saver... perfect demonstration.

[@gotmymojoworking2010]

Wish I seen this last night. I spent a bit of a frustrating night and finally just turned off my furnace. It was our first night in our trailer and we got chilled and turned on the furnace. Was happy about how fast it warmed us up but could not figure why the AC was running. Now thanks to you I realized it was only the fan.

[@darrellholland3653]

I have spent a lot of time trying to figure out what was wrong my air conditioner and you just made it simple as pie thank you so much to bad my local tv tech don't know what it was doing Thanks again

[@darrellholland3653]

Sorry RV tech

[@dwanehoughtaling419]

Thanks for another great video. I have the CT Thermostat that's very similar to this model. Found the CT manual on your web site for things unique to the CT model. The final tip on the C to F change is great. I've got one thermostat in C and one in F. Now I can set both on F.

[@Jhoite]

Omg!!! Thank you, thank you, thank you...... I just scheduled a service drop off today for next month because I though my new a/c ( which was just installed in February) was malfunctioning, you did a great job explaining it and saved me some money in the process, thank you again and I love your videos.

[@MyRVWorks]

So glad I can help you guys out. Happy camping.

[@thetaniatouch]

Thanks a million! I bought my used rv months ago and thought my AC was old and had dementia 😆😆😆 This video is helpful!

[@scovillesadventures7141]

Very good explanation. I have heard my fan shut off while the compressor ran before. Never thought that it had to shut off to switch modes.

[@torrieavey3401]

Thank you so much!!! This was incredibly helpful and saved me a call to the service department!

[@daryllect6659]

_"...saved me a call to the service department!"_ Which would have been a _complete_ waste of time because your dealer is absolutely clueless as to how to operate one of these worthless, hard to use, unreliable, overly-complicated pieces of Dometic crap. (And Dometic used to be so good, too)

[@stephentrebolo4233]

Thanks for the great explanation! Last year I learned how to repair my cable slide from your excellent video on that subject as well!

[@edwardlkent3508]

Thanks I have a different type of dometic thermostat, but it works this way you set fan speed the choose ac or furnace then temp it all makes sense now

[@mooseman3136]

Thank you! Never understood why it sometimes stopped and restarted for no apparent reason. Thought it was a power problem.

[@dinahbecker9669]

Omg, thank you. I was about to replace the thermostat because the ac would not stop! I had the fan on high. Never paid attention to the fan.

[@nighthawk8764]

I don't own an RV, but you are making me want to buy one just so I can fix stuff on it. LMDO!!

[@TomSommer]

Your my favorite RVTech. Thanks for another great video. The only thing you did not cover was how to set the differential. There is a 2 or 5 degree differential you can set.

[@MyRVWorks]

I made a note to add the Diagnostics mode to the description of the video. I'll probably do another video demonstrating this as well. I also have about 40 more service manuals to upload specifically for Dometic air conditioners and thermostats.

[@MyRVWorks]

I have added to this description of the video to include Diagnostics mode and error codes.

[@larmo5980]

i love watching your videos.. you are such a great teacher.. i am going to open my own mobile rv repair in florida.. thanks for all the help and info...

[@MyRVWorks]

Glad I could help. Good luck in your endeavors. I have many more videos in the pipeline.

[@stevedionne1931]

Finally someone that knows how it works Bravo Zulu!!!

[@markmosqueda9644]

Appreciate your time And help!!

[@mikewebster2984]

Thanks a lot, great video, now I understand the thermostat finally

[@chardonlacrosse2939]

fan running constantly while in furnace mode even after furnace stopped heating because it reached temperature, was driving me crazy....thought something was broken or shorted out. Thanks for great explanation of all the details.

[@jeffwoolyhand9759]

Thank you for the great video what I did I put a plastic bag over thermostat that way it doesn't shut off as much and I stay nice and cool💯

[@ceetee2021]

Excellent demonstration. I have that model and have a much better understanding of the operation.

[@joannaminton2268]

Wow, best explanation. Thank you!

[@rickcooper9034]

Youdid a great job explaining this Great video

[@jamiebrandrick8865]

Great explanation!

[@richardjimenez5605]

Attention to detail luv it, thanks for all you do !

[@adriandostan1919]

Oh if I new this before taking the furnace off from its place and trying to figure the problem why is not turning on. New owner and I never heard the furnace running. I thought that the problem was in the furnace. Good video

[@vickieclark3052]

Great video, we now understand why our fan runs all the time. We changed our differential to d1 and when we did that the thermostat went off and will not come back on. Please help!!

[@weloveourkittens]

Can you change the differential on this Dometic Thermostat. I have the exact one and can't figure out how to change the differential.

[@steelpix]

Really excellent. Now I know how to operate mine correctly.

[@marcelorivero5608]

Thanks you so much for the video..cuestión my ac in the rv never turn off even when set the high point 32 degrees celsius..ac spent electricity when is on? A live in Miami 😢..😅

[@MyRVWorks]

On that display, check to make sure that the fan mode is set to 'Auto'. I suspect your fan mode might be set to 'Hi' or 'Low'.

[@marcelorivero5608]

@MyRVWorks yes I found out the fan mode was in high..already move to auto. Another cuestión the furnace mode is a 90 degrees set..I turned off? I need that mode on in Florida with 95 degrees? Thanks

[@parneypots]

A bit wordy but I watched entire video. Thanks for the tips

[@beepsarieaniIwee]

My bedroom AC keeps shutting off at night after a few hours on low fan. I raised the temp up to 64 and it ran for 3hrs and shut off again the next night. It’s been in the 90’s during the day but does cool off by morning into the upper 50’s. I have to get up and turn the floor fan on☹️ My front AC did the same thing one morning but fan was on high. Ran for a couple hours then shut off. It’s like their in Auto or huts a certain freezing temp and shut off. I even changed one domestic thermostat for a new one. That’s my vent.

[@jondutra1474]

You ever get to the bottom of this? My ac turns off too, even though it’s on low, during middle of the night.

[@charliehooks5801]

Lol thanks man.. I have a Coleman mock and it was doing that I noticed if I turned it down it would stop doing that and continue to cool but then if I tryed to turn temp up a little later because it was getting cool it wouldn't shut off even if I went to 90. So been wondering if I need a new thermostat.. The on off part I had a feeling was related to being on that boarder line zone but not sure after turning it done to stay cooling why when I turned it up to shut off it would not.????

[@bonniedickinson8230]

Thank you very much great video

[@deemartin2265]

Very helpful I jave my thermostat on auto- furnance but I get no hot air

[@TWegnerPhotography]

Great explanation. If you get confused while camping and just want heater on and fan keeps coming on this should help out. If still confused just flip off the a/c breaker and problem solved when using furnace.

[@pennyharn4958]

Thanks for your help now I know how to use my air conditioner properly, but now when I use my furnace since it's cold here in WA again my furnace is making a clicking noise before it starts and shuts off. Did I do something wrong in my settings when I did the air conditioner

[@MyRVWorks]

No, but in that video in description I list the procedure to get into the Diagnostics mode of the thermostat. One of those modes, I believe it's 04, you can start and stop the furnace to verify if there's communication there. Check out my playlist on furnaces for a plethora of furnace repair videos: kzbin.info/aero/PLk44vSl27TRCaZIQbm-0utYK7sVOKwXVY

[@pennyharn4958]

@@MyRVWorks I tried the diagnosis but nothing shows on the screen when I pushed the plus and minus

[@clintonlemarluke1507]

Thanks for mystifying this frustrating thermostat.

[@bryanplatt5842]

First time I have understood my thermostat operation and know am thinking I have another issue...first thing in am I turn on furnace on low to 70 degrees. Unit runs fine until temp is reached, turns furnace off and then never turns on again, regardless of drop in indoor temp, unless I turn the thing off and restart it. Any suggestions on where to Look? Thanks! Bryan Platt

[@bryanplatt5842]

As I have continued to work on the settings, the furnace turned on in the middle of the night, and checking the indoor thermometer, I now see that it will turn on normally once there is a 10 degree drop in indoor temp. Surely 10 degrees is an unacceptable temp drop before the furnace turns on!!!???? Now, how to change the turn-on point to a few degrees?

[@MyRVWorks]

Hi Bryan, Your question has been selected for an upcoming video where it will be read and discussed by Darren. If you have not already subscribed to the 'My RV Works' KZbin channel, please do so and keep a watch for the '10-Minutes with an RV Tech’ video sessions. This new series is a selection of comments and questions that will be covered and released weekly. Here is our KZbin link: kzbin.info Happy Camping, My RV Works Media Team

[@weloveourkittens]

@@MyRVWorksDid you ever do a video on setting the differential. I could not find one in your list of videos.

[@jasonthorpe76]

Great video! I have the newer thermo with the blue back light. Spring break camping and it’s cold. Have the furnace on, fan auto, set to 90° and it’s not coming on. Any suggestions? TIA

[@davidpowell9851]

Big fan of My RV Works and I can’t thank you enough for educating me about a number of issues I’ve had with my Montana 3730FL. I operate my two domestic whisper quiet with no leaking from condensation through return vents but twice I’ve experienced leaking slightly while operating the rear a/c while it was raining. I examined the A/C carefully but I must be missing something. Do you have any ideas ?

[@MyRVWorks]

You can try this, remove the ceiling plenum inside from the bottom of the air conditioner. Once removed, at Each corner you will find long bolts that screw into the air conditioner on the roof. Make sure those are tight. There's a gasket that is between the air conditioner and the roof membrane and you need to make sure that has a good compression.

[@davidpowell9851]

Thank you so much for the education on my a/c leak because last night we had our first rain and wind storm since I received your instructions and I’m happy to report no leaks. Not only am I grateful for the guidance you gave me but I’m more impressed that you would take the time to reply to my comment, so please keep up the good information because you are a god send for amateurs like me.

[@judyhall4828]

Okay so I have thee exact thermostat still not sure how or what I should have it on as far as the furnace goes. I’m not sure as to what I need to do. Fan on auto/low and on 80 is that right in order to keep it warm in here and can I let it run all night?

[@trevorclough2148]

well explained. thanks

[@georgemann9213]

Thanks for sharing.

[@georgemann9213]

Saved me $100. Thought my thermostat was bad. Was about to go buy a new one.

[@seanhoff5428]

So on auto cool once I hit the desired temperature it still won’t turn off right?

[@beelust4312]

Any tips to why my RV electric heater stopped blowing my air? Fan Blowing great. Thanks

[@biblesnbarbells]

Thank you for this video. I have never used my RV furnace since I purchased my Forest River R Pod 179. We lived in South Florida at the time. Now we live in Charlotte, NC area and I want to start using it. Any tips before I test it out? Anthony

[@rickmathews4101]

On the furnace side why would it turn on initially, but after reaching temp and turning off the furnace won’t cycle back on when temp goes below thermostat setting? Thanks

[@amandamoore3048]

Our ac sometimes doesn't kick back on on a hot day if we set it to auto (very cold on high) is this a thermostat issue?

[@davidbacajr564]

Great video! Thanks.

[@LordFalconsword]

That little speed switch was driving me nuts. I was sure I had a bad AC. However, mine will throw the breaker on hot days, and a new thing now, the thermostat just won't make the AC come on no matter how cold I set it. If I turn it off on the thermostat, then back on, it returns to normal function. Someone suggested a bad start capacitor? It's not even 1 year old.

[@TheKKHawkins]

great video +explanation

[@pensacola07]

Continuation, when my furnace is on, one of the vents in the bedroom is blowing cool air instead of warm and it's been like that since I bought it, any suggestions on why?

[@MyRVWorks]

Some might say that the benefit is the fan will circulate the air throughout the coach balancing out the hot spots and cold spots. For the cold air blowing in your room, that sounds like one of your ducts has a breach or is not connected to your furnace.

[@Stixismyname]

What if you have it set on high but the fan turns off when the ac stops? Is it wired incorrectly?

[@jesustapia5384]

I got a question, I have a 2021 Dutchman and an E2 code is coming on my fridge ? Why could that be and I’m a new camper

[@claytoncomeaux414]

Oh ,im sharing this!

[@Whateverpogi01]

Does the Generator need to be on or plugged into the house ????

[@BudlightBoe]

Can anyone explain to me why my AC stays running all the time like I thought once it hit a certain temperature it's suppose to kick off

[@kevinfetty1309]

How can I replace my Dometic 3309705.022 thermostat? It has the phone cord plugin, which, in fact, is a comm cord that is wired different than a phone cord from what I've found out. I've called Dometic. ZERO help from them. Camping World wants to sell me stuff that isn't right....can I use ANY thermostat with a comm cord plugin? Like the 4 button old one that I THINK is still available. Please and thankyou for any help! I'm going nuts trying to fix this and it's suppose to be in the teens here in Colorado this weekend.

[@billandjanlloyd5252]

Love it!

[@jesustapia5384]

Dude God bless you

[@joras7457]

Does the furnace have a separate fan? Or does it use the roof top unit fan

[@MyRVWorks]

The furnace has its own fan. The furnace operates as a standalone unit. It only gets its start signal from the thermostat. Typically your furnace will blow the hot air from the floor or registers close to the floor. Your air conditioner fan will blow from the ceiling ducts. Again two totally separate systems. They only share a common thermostat and since the thermostat communicates with the control board in the air conditioner, the furnace runs wires up to that control board only for its start signal.

[@pensacola07]

What is the advantage of having the fan on and the furnace on at the same time?, and also when my furnance

[@cheveco1981]

Air circulation advantage!!!

[@dave091125]

Thank you outstanding.

[@fisherwomanforJesus]

Ours keeps going off and coming right back on w ac on. Could it be a sensor ?

[@jamesbroderick3660]

Hi sir I hope you see this. I’ve been watching you for a while now and I have even went and looked at all of your videos but the one thing I can’t seem to find is. A video on having a problem worth the black tank and what I mean by that is. Say there is a clog in the black tank to where you have to take the black tank down. I have a 2018 Keystone hideout and I think I’ve got a problem. Yes I have tried everything you can think of to get it unstuck lol. But this is the one area where I need help

[@MyRVWorks]

I have created an attachment that I use a dedicated 16 gal Shop-Vac for (For obvious reasons). For the attachment I took a long clear section with the Bayonet fittings so I can put it in line with the sewer hose. Then I cut that section in half and used a flexible 3" Wye reattaching the clear section on either side. And leaving the angled part available so that I can slide in a 3-foot piece of pipe the same diameter as my vacuum hose. I also added a separate termination valve ( with the bayonet fittings) so that I can control the vacuum pressure directed towards the tank and then open it once the flow starts. This adapter and Shop-Vac 'tool' has cleared many, many clogged tanks. I will add this tool to my video queue and send it out soon.

[@jamesbroderick3660]

My RV Works, Inc. thank you sir. I’ll give it a shot and see how it goes.

[@melodyfulweiler7489]

Ok I'm having a problem! Full propane thermostat seems to be on 31 but can't get the temp up on my heater. I'm freezing

[@brianbrown6978]

If I could only figure out why my furnace won't cut on at all. I have that same switch

[@boss-tech8513]

What's the purpose of having the fan on with the furnace, and y doesn't it show the current temp on display?

[@MyRVWorks]

Some folks may opt to run the fan only in the ceiling while the furnace is blowing the hot air from the floor. They might do this to help circulate the heat throughout the RV. But as we all know that gets kind of noisy. Regarding the temperature display, I really wish they would display that. The thermostat knows the temperature but for some reason they chose not to display it. The next model thermostat up from this one does show the temperature. However, In the description of that video, we list how to access the Diagnostics mode on that thermostat. Within the Diagnostics mode you can read the room temperature.

[@jimtamilio]

I have the same thermostat. Can you tell me why my thermostat is flashing an E4 code.

[@MyRVWorks]

Down in the description of that video we listed all of the error codes and how to access the diagnostics mode.

[@JM-uk2ci]

Can you recommend me to an RV parts dealer.for door locks ac parts.ect ac thermostat.thanks

[@largecartransport9514]

I have a 2011 keystone raptor.... The 5500 onan evap generator is not charging the battery when running and the battery goes dead....what should I do to troubleshoot?thanks in advance

[@MyRVWorks]

On most coaches, near the battery within a few feet, you should find a circuit breaker fuse or something like that. You can check to see if that fuse is open or failed. If you are getting 12 volts in your coach for lighting, and things like that, then you can assume that you're converter is fine but on some converter/chargers there is also fuses on the converter/charger that may be separate from your panel box fuses, so look there as well. I've got several videos in my playlist that might help cover your situation.

[@stephengudac3527]

Thanks that helped alot

[@dontask8979]

Well explained 👍

[@thebluetravelers7544]

Thanks for video analogy so listen to this ac in camper the fan wont come on and I've got voltage coming from thermostat fan wire going into circuit board and I've got 110 going to it I have replaced circuit board and it's still same so what I've done for now is hotwire high fan low fan switches just the red wire tho to the 110 blue wire that is going into circuit board and it works for now by hotwiring it but I'm boggled by why my high and low fan prong connections are not being energized when I have a good thermostat and everything else checked out good going up to it! Please help if you can think of anything else to check she said converter needs replaced also

[@MyRVWorks]

On the description to my thermostat video, I added how to access Diagnostics mode into the description section. So try this, access the Diagnostics mode and cycle through the commands. Low fan speed will be commands 01 high fan speed will be command 02 see if you're getting good communication from the thermostat to the control board.

[@daviscrt]

great video

[@jacquelinelloyd2717]

How do you get it on AU

[@DANIELROMERO-cv3tu]

Great video I thought it was a bad board when my ac fan would not turn in furnace mode. That answered my question. Thank you

[@thomasheaney2087]

Thanks

[@davidpreece3616]

Dude, this all Greek to me! When it’s 95 outside I want my unit to be 70 on the inside. How do I do that? I never use my furnace here in Texas so forget that furnace stuff. Just want it COLD!

[@davidrobards9587]

Turn the cool on 70. Heat to 50 or what ever. It will cool. Fan can be on low, hi, or auto up to you it will cool in any of the fan speeds.

[@neni_minaj]

i have e1 ?????? what do i do ? any help

[@MyRVWorks]

Expand the description of the video. There is more info and error codes contained there.

[@sylvierichard1168]

Why my furnaise don’t start Fan and cool ok