Replacing a/c dometic

[Les Hurdle]

It looks to me as if it is going to be wise to keep old machines running as long as possible........... is there a scrap yard somewhere for older a/c units?

[Dennis N - 2005 Windsor]

I, like many have replaced a couple of fan motors and capacitors over the last few years. When our rear unit quit putting out cold air, (it was probably the valve that switches it from air conditioner to heat pump), we decided it was best just to replace the two 18-year-old units. The new 15 kbtu heat pumps are almost $2,000 a piece now. But the idea of being on a trip and an AC unit going out again convinced us the replacement cost was justified. Talin RV is doing the work for us right now. Talin indicated a aftermarket thermostat could void the warranty on the units, so a new 10 button dometic is also being installed. Although it's expensive, I decided it was best to replace it all, have someone else do the work, and know that it's all done right so that we can enjoy using the RV instead of working on it!

Edited May 22, 2023 by Dennis N - 2005 Windsor

[jacwjames]

25 minutes ago, Dennis N - 2005 Windsor said:

I, like many have replaced a couple of fan motors and capacitors over the last few years. When our rear unit quit putting out cold air, (it was probably the valve that switches it from air conditioner to heat pump), we decided it was best just to replace the two 18-year-old units. The new 15 kbtu heat pumps are almost $2,000 a piece now. But the idea of being on a trip and an AC unit going out again convinced us the replacement cost was justified. Talin RV is doing the work for us right now. Talin indicated a aftermarket thermostat could void the warranty on the units, so a new 10 button dometic is also being installed. Although it's expensive, I decided it was best to replace it all, have someone else do the work, and know that it's all done right so that we can enjoy using the RV instead of working on it!

This is what I did in 2021, at the time I bought two high capacity 15K BTU heat pumps for $2700 including shipping and tax.  I did decide to go with the MicroAir thermostat, in all the posts I read on here and the IRV2 forum never heard of a issue with a voided warranty but I guess it's not out of the realm of possibilities. 

I did the work myself, it was pretty much plug and play but the new AC's came with a fancy connector, I didn't have the house side so I just cut it off and hardwired it. 

I have not had any issues with the AC's or MicroAir thermostat.   In moderately hot weather (high 80's) one of the 15K BTU units could keep the coach cool. 

But one thing I did prior to installation was buy a remote camera to inspect my duct work, glad I did, had several holes from mice/varmints and there was one duct joint that was not sealed taped and allowed for a loss of the conditioned air.  see picture, this is the top of the vent and the air just dumped up into the area below the roof.    I was able to fix the holes pretty easy but the gap was another story.  It was between two ducts and no way to fix it so I just cut a hole to repair and then added another duct.  Can't even tell it wasn't suppose to be there.

Edited May 22, 2023 by jacwjames

[Dennis N - 2005 Windsor]

4 hours ago, jacwjames said:

But one thing I did prior to installation was buy a remote camera to inspect my duct work,

That is a great idea! Can I ask what camera you purchased?  I have lots of uses but don't know where to start the research... Years ago I bought a USB connected camera but the focal length is not appropriate; only good for very close items.  

[Tom Cherry]

I purchased this one.  It does fine for my use.  I THINK that @Frank McElroy has the same one....so, I just piggy backed on his research. I use it with my iPad so I have a larger image.  Old eyes....like this better than iPhone, but it just depends.  Easy to install.  Just gotta follow the instructions.  From Amazon.  It is highly rated and not a fortune....

Technology is unbelievable.  I have a buddy that has a similar one, except it is for your ear canal and he says that it is almost as good as the one that our ENT (we both have hearing aids and have annual ear exams prior to our Audiograms) uses at a major (never bought anything cheap) teaching hospital uses....

 

DEPSTECH Wireless Endoscope, IP67 Waterproof WiFi Borescope Inspection 2.0 Megapixels HD Snake Camera for Android and iOS Smartphone, iPhone, iPad, Samsung -Black(11.5FT)

 

[jacwjames]

I bought a cheap one off Ebay and it surprisingly worked pretty well.   https://www.ebay.com/itm/264797559966?var=564621749467

The wire that it uses to communicate to my laptop is stiff but not stiff enough to control it.  So I had a long flexible piece of wood that I taped the camera too and I was able to push and control it and monitor the screen.  The piece of wood was ~8' long so I had do the front going up through the AC return vent, then turned it around and went the other way, then had to take down one of the vents in front of the kitchen and work may way back. 

I found holes at each end of the ducting, which I couldn't reach to fix but what I did was took a piece of sytrofoam and cut it in a wedge shape and placed it in the end ducts sot that it sealed the back portion and then forced the air directly down/out the vent.  I think this help on reducing turbulance in both the front and rear ducts resulting in better air flow. 

There was a larger hole ~1/2 forward of the front AC but luckily it was right above one of my ceiling lights and I was able to remove it to gain access to repair the hole. 

And then adding the vent to fix the separated duct work fixed all the leakage in the ducting. 

I ran/tested each AC last week as my wife is getting ready to go to the Asheville dog show.  I ran each individually on all 3 speeds and was pleased with the amount of airflow I was getting out the vents.   My bet is she'll easily be able to run one AC to keep the coach & dogs cool.  And at night she can run the front AC to keep the bedroom cool. 

Edited May 22, 2023 by jacwjames

[hbr509]

Well after alot of bs I bought the dometic 10 button thermostat and it was plug and play . Works with the original phone cord .  all better now . 

[amphi_sc]

1 hour ago, hbr509 said:

Well after alot of bs I bought the dometic 10 button thermostat and it was plug and play . Works with the original phone cord .  all better now . 

As I bought heat pumps and since Dometic changed the logic/default state of the reversing valve, an old board couldn't work for me so I had to buy the backward compatibility board or new compatible thermostat. But my understanding at the time was a straight A/C unit could have worked by swapping old board into new unit with caveat losing the 3 speed fan settings.  I wonder if the fuse on your old board was good?  Were yours straight A/C units or heat pumps?  Anyway, mute points since you say all is better now.

As for "keeping old machines running", the new penguin's have a much stronger cover that I think will hold up better than the thin fiberglass glass of the old units.  Also there is styrofoam insulation around the box for exchanging hot/cold air with the house that would seem to help efficiency. From the start up noises the new makes compared to the old it almost seems like the new starts smoother, and my Aladdin doesn't show a big spike with inrush current anymore. I wonder if the newer boards offset the fan and compressor startups? After a certain age I think it makes sense to replace old failing units with new rather than trying to keep 15-20 year old units running.  With that said I'll add that the longevity of the new Penguin III model is yet to be proven.

My experience with the Microair is okay with the caveat that I have to set a temperature about 3 degrees off from what I really want.  Verified by "what my body feels" AND with a couple different thermometers sitting on that thermostat that show a different actual temperature 🌡️ from the Microair.  I compensate by learning I need to set a temperature 3 degrees from what I really want.  The Microair is the only thermostat that will physically fit in the narrow wall space where my original 5 button was mounted between my cabinet and my bathroom door.  Your wall space could be different.

Just my 2 cents...

[jacwjames]

Another positive thing about the newer Dometic that I bought is that there is a removable cover over the internal fan that can be removed to clean so now both the condensing and evaporator coils can be cleaned easier. 

I also notice that the set temps have to be different on each unit.  The thermostat has an internal sensor and is mounted on a cabinet next to the bed and seems to read a little higher then a stand alone thermostat.  Front sensor is mounted on the underside of an overhead cabinet and depending on direction of sun will cause hot/cold swings as the AC tries to keep up.  But that happened with the old thermostat also and I've just learned to live with it. 

[CAT Stephen]

On 5/21/2023 at 10:01 AM, Les Hurdle said:

Hi Folks, newbie here.

v- 13.5K BTU Low profile version: https://www.recpro.com/rv-air-conditioner-low-profile-13-5k-quiet-ac-with-heat-pump-remote-non-ducted/.  will the shroud/cover of the old [to be replaced  unit] fit the new unit so roof appearance will be the same?

Have to admit I am finding the incompatibilities somewhat scary [even silly].  Years ago when MIDI was introduced the musical equipment companies decided on a global protocol so all product 'talked' to each other.This is also the case re DAW's and plug-ins etc.

How come RV'ers haven't yelled at the manufacturers to be compatible? 

Les

Hello Les,

 

All rooftop AC units are custom and unique to a manufacture's product series.  For example, the "Dometic Penguin 2" series shares a common shroud/cover.

Thus, the shroud/cover of the old unit to be replaced will not fit the new unit.

If you elect to utilize the Houghton (RecPro) products, these units are entirely self contained and independent of your current thermostat.  But, you still need to keep your current thermostat installed to run your existing propane furnace.  Nothing to fear and easy as pie! 

[Les Hurdle]

Ok Stephen thank you.

 

Anyone know of RV HVAC people in the Antelope Mohave Victorville area?

 

Les

 

[Tom Cherry]

5 hours ago, CAT Stephen said:

Hello Les,

 

All rooftop AC units are custom and unique to a manufacture's product series.  For example, the "Dometic Penguin 2" series shares a common shroud/cover.

Thus, the shroud/cover of the old unit to be replaced will not fit the new unit.

If you elect to utilize the Houghton (RecPro) products, these units are entirely self contained and independent of your current thermostat.  But, you still need to keep your current thermostat installed to run your existing propane furnace.  Nothing to fear and easy as pie! 

YES….but you also need to remove the control modules from each zone and reinstall them snd keep them functional to allow for furnace/AquaHot. The new units have their own thermostat system and controls and do not have an option, as of now, for integrating the existing furnace/Aquahot control circuits.  Therefore, the out of production 5 button thermostat and the older control modules must be functional.  

The concern is that for heat one has to eventually replace the 5 button with a Microair ($300), assuming that the control modules will continue to work.  Otherwise, you need to replace the thermostat with a new CC2 or the equivalent Microair and also upgrade the control modules.  Just a matter of understanding the restrictions, parameters and evaluating the pros and cons as well as the total cost….New technology vs replacing 20 year old components, and their availability.

It would be good to have a white paper on how to do this and the steps…..as well as the costs.  We have had more questions about how to salvage a conversion than comments about success..  The concept is “easy as pie”, but the actual implementation has been the the topic of several threads as to “how do I fix my installation”.  If one is knowledgeable and understands the Dometic system, it should not be that difficult….but there are other threads on other sites where the Tech that did the install was less than knowledgeable….far less.  The result was running wires to a wall thermostat….as there are no Furnace/Aquahot control wires inside the walls….from the ceiling and down the wall…and that takes a special thermostat for each zone…$50 - $75 each.

Thanks in advance for some straightforward instructions and pictures.. i can provide the info on a self contained thermostat if needed.

[Dr4Film]

On 5/19/2023 at 2:15 PM, CAT Stephen said:

Key here is that the Houghton rooftop units (RecPro) allow you to completely abandon the expensive and complex interface boards and manufacturer specific thermostats as their controllers are self-contained in these units.  You may also remotely control these units via a SwitchBot infared repeater provided that you have an internet connection on your RV.  These units do not attach to your existic Dometic controls as their controls are self contained.

Compared to spending $100s on controller boards and MicroAir thermostats, the RecPro units are a bargin and are tremendously quieter than Dometic, Coleman, ect. 

 

You will still need to keep your legacy Dometic thermostat installed to control your furnace.

Not true!

The furnace or Aqua-Hot functions through the control board located in the roof AC using the data cables. Without that control board the furnace will not function.

The Houghton Rooftop AC's are a good replacement providing that your current AC system is a standalone system controlled with either a 4 or 5 button CCC and your furnace is controlled by a completely different and separate thermostat.

[Les Hurdle]

Hi Tom,

Found this. https://www.etrailer.com/question-613963.html. is it helpful?

 

 

[Tom Cherry]

47 minutes ago, Les Hurdle said:

Hi Tom,

Found this. https://www.etrailer.com/question-613963.html. is it helpful?

 

 

Wonderful answer.  Maybe on the 4 button Thermostat….but not on the 5 button ones.  There are NO dip switches inside the 5 button systems.  I have had mine apart down to where the actual buttons come out.  I have cleaned the carbon pads on them.  If you ever take apart any modern car remote, the buttons have a “carbon” pad on the back.  When you push a button, the carbon pad then contacts an “array” on the PCB.  That array is like a maze of 2 circuits.  See the photo.  When the carbon pad contacts or covers the array, a circuit is made.  That is how the buttons work on the 5 button system.  There ain’t NO DIPS in that thermostat….i know….nor has anyone EVER discussed or talked about them.  

OK….for the record….i found the Dometic 4 button thermostat and system trouble shooting guide.  Same deal. There is Nothing to set or do to the Thermostat.  It is “snapped shut” jut like the 5 button.  NO internal DIP switches.  The control modules with it are different so the DIP settings are different.

Here is a picture of the DIP for your units. The only DIPS are in each INDIVIDUAL control module and they are labeled very specifically.  DIP 2 & 3 & 4 are for designating zones.  If NONE are turned ON….that control module is Zone 1.  DIP 5 is for controlling a “furnace”.  Furnace means either a gas one or an Aquahot.  See the infamous BLUE wires.  If there is a furnace for zone 1, then that DIP is ON.  All it does is act like a dry contact switch.  When the thermostat calls for heat in that zone, the blue wires are jointed and make a circuit.  There is NO voltage on the wires.  If you had a middle zone, but NO furnace….the nomenclature assuming one upfront AC, Middle AC and rear AC would be Zone 1 & Zone 3 (rear bedroom)….FURNACE DIP ON.  Zone 2 would be OFF.  In that scenario you would have ducts from each furnace in the middle and if zone 1 furnace was on….the cross over cuts to the middle would be blowing…same for zone 3.  In the Aquahot system, it is the same,  I have two zones,  Monaco originally labeled them 1 & 3.  Confusing so I changed the rear to zone 2.  When the Aquahot comes on for the bedroom, it heats the hall and bath….and I have a wall switch for the bathroom if it is too hot,

Bottom line.  The E-Trailer lad is wrong as the 2005 Endeavor has a 5 BUTTON thermostat.  See the screen shot from the manual.  He reminds me of the MicroAir tech support folks I talked to, when they would talk to you…now ONLY EMAIL  They have reverse engineered and sell two different thermostats.  One will work with a 5 button as well as the other, a different one to work with the new 10 or 12 button units..  WONDERFUL.  But they don’t have a clue about dip switch settings or compatibility.  All they say.  YOU MUST HAVE A FUNCTIONAL HVAC SYSTEM….or all the modules and the units are working.  If so, our thermostat will work, assuming you order the exact replacement for the type, old 5 or new 10/12 button.  We cannot assist you with trouble shooting if there is a communication cable issue or any control or electrical issues within the systems….contact Dometic.

LES….my past several posts have said this.  Either accept that your 5 button thermostat, which has been taken apart and appears from your posts to be flaky as some functions don’t work as they should and then look at your alternatives.  We talked about those on the phone.  If you don’t want to replace the two units with Dometics and upgrade to the new CC2 thermostat, then find units that the vendor and your “guy” say will work.  But there is no system out there that will install if it requires 5 or 6 conductor cables…or has a “state of the art” BT digital thermostat that will interface with your existing furnaces.. You only have phone communication cables.  They are multiplexed and NOT hard wired analog.

Therefore the Rec Pro or whatever will not control your furnaces.  It (thermostat) does NOT have the ability to turn on or off a furnace nor the furnace mode.  If you want them, there is a thermostat and BT for each unit or zone.  BUT, you have to keep your old control modules and have them gutted and rewired to work with the phone lines or communication cables.  You will need a rebuilt 5 button thermostat and it will be a bit funky as the AC and HP zones will show up..,but are NOT connected to anything.  The Furnace zones will work, if the tech understands HOW to salvage them and connect the two furnace circuits.  They have to be installed in a separate box or enclosure and fitted inside the plenum in the ceiling.  Folks have done this.  Many have not understood and failed and ran separate on the wall with exposed wire mold strips and abandoned the 5 button thermostat.  If your guy understands this and knows how to gut the old units, rewire the control modules and mount them and hook up the power to and the wires to the furnace and then can do a reboot and the new thermostat (rebuilt or MicroAir) works…good to go.

BUT, there are few techs that do.  We have more hands on knowledge and experience here….some shops read us to learn.  It is just that simple and nothing has changed since we talked several months ago.

The E-Trailer guy is wrong.  Your 5 button thermostat does NOT have internal DIP switches….  But, it is your call.  

This is what I and others that understand the systems plus the ones that have made, as well as failed, to integrate the 5 button (or 4) thermostats with the Rec Pro.  The E-Trailer unit does NOT appear to work with the 5 (4) button thermostat that came in the 2005 Endeavor….there ain’t no DIP’s in either thermostat.  How it will work with your system since you do not have a thermostat with DIP switches is beyond me.  If your guy says he can make it work, then get a full warranty and if doesn’t, he charges you NO LABOR to install the correct new Dometics and you buy the hardware and E-Trailer refunds the cost of whatever you buy from them.

This is a NEW world of electronics.  I had my daughter my GK’s 2011 Nissan Maxima to our local Caddy dealer.  The service manager said he THOUGHT he could replace the MAF sensor and it would work and he would clear the codes and the SERVICE ENGINE light would go away.  He had his parts guy pick up an aftermarket, guaranteed to work, MAF.  Light came back on after 3 drive cycles.  The service manager took it to the Nissan dealer.  Any NEW MAF must have the ECM programmed snd calibrates for the new unit.  They did that.  Light still on. Then they tried again as they ASSUMED it was an OEM MAF from Nissan.  Nope…OK, Nissan’s software has an option for a NISSAN approved MAF.  NOPE.  That MAF was NOT on the list or made like the Nissan.  Finally…put in a OEM Nissan MAF.  WORKS!  I talked to the Caddy tech and service manager and the Nissan tech and service manager.  That is how i know the gory tale.  

Your system is way more complex than the above.  But…it is your call.  Let us know if you decide to go the ExTrailer way and the results after your guy installs it and gets your 5 Button NO DIP thermostat to work.  It will be a first and then others will have options….