Dometic Dometic™ Penguin II Trouble Shooting. Any technical people out there?

[Nik]

I bought a used Dometic Duo-Therm 641815C Penguin 2 on facebook marketplace. I then purchased the required thermostat (Dometic 3314080) and hooked up the 120v and the 12v to the Penguin and the phone plug (RJ11) coming from the Penguin to this new thermostat.



Nothing happens. The LED on the thermostat doesn't light up. 120v power is getting inside the unit. I tested it in its power box.


Any experts in this field out there? Or can anyone recommend a highly technical forum? Thanks!

[Raspy]

What did the previous owner tell you about it?

Did the RJ11 wire and plug come with it?

Are you sure you don't need an RJ45?

[Civilguy]

The Panther RV site selling that air conditioner seems to suggest that the compatible thermostat is a Dometic 3314082. The CCCII board seems to be the factor they are noting.

https://pantherrvproducts.com/dometi...w-cccii-board/

[Nik]

I overlooked the one digit. I ordered from https://www.rvpartscountry.com/Domet...hermostat.html
Their site shows the model ending in "2" not "0". They sent me an older model. But I find it hard to imagine both wouldn't work. The box the T-Stat came in doesn't list my "64XXX" series Air Conditioner, either. I assume my AC hadn't been built yet.

Dometic sent me a detailed manual for their thermostats and they don't refer to different model numbers. They refer only to "the CCC 2 Thermostat."

DIAGNOSTICS:

The T-Stat does light up when I apply 12v to the two center wires on the RJ11 plug. It does not light up when connected to the Air Conditioner's RJ11 plugs. (there are two RJ11 plugs from the AC. Only one needed with one zone.)

Apparently there's no 12v getting to the T-Stat when it's connected to the short RJ11 plug coming from the AC.

Opinions - experiences?

Thanks to everyone. I know this kind of post isn't for everyone, so I really appreciate the guys who enjoy diagnostics.

[Civilguy]

Hmm. CCC2 "sounds" equivalent to CCCII. So, it "seems" that you do have the proper thermostat.

If there are only two wires between the unit and the thermostat, then one would be power and other one would return power to the air conditioning unit when the thermostat is actuated and calling for cooling.

However, these two wires would not provide power to the thermostat.

Normally there would be at least three low-voltage wires; power (from any source), switched power (the output" of the thermostat's circuitry back to the AC unit), and a ground which would provide a return circuit so that the thermostat's circuitry could be powered by the trailer's 12 volt power, (or, less likely, powered by a transformer in the AC unit supplying some special voltage to the thermostat).

Does this make sense?

Does the thermostat have or require batteries?

[Nik]

Sorry, I wasn't clear.

The only wire from the Air Conditioner to the Thermostat is a standard four wire flat cord telephone plug (RJ11). The middle two of these four wires provide the 12v. The outer two wires on this flat plug provide data
I opened up an old RJ11 jack and connected 12v to the two middle wires. The Thermostat lights up.

But when connected to the Air Conditioner by the Air Conditioner's RJ11 plug the Thermostat does not light up.

So the Air Conditioner is not providing 12v to the thermostat. That's the first thing I've determined.

The Air Conditioner requires 12v input and 120v input.

[Civilguy]

Well, I don't know that this will provide any help but here's a one thought based on a quick fan through the 18-page manual from the Dometic site.

Figure 4 on page 6 of the manual indicates that the RJ-11 cable, referred to in the manual as the "communication cable", should have the connectors flipped so that the plastic retainer is on opposite sides of the flat cable. This point is echoed on page 11:

"Important: RJ-11-6C4P connectors must be installed
with the same polarity on each end. Standard telephone
cables will not operate the controls."

Other than that, they appear to describe the additional cabling requirements and the dip switch settings pretty clearly, with good quality illustrations and wiring diagrams. In other words, I don't see anything else that really pops out.

[Nik]

Thank you, Mike, for diving so deep into this issue. You may be onto something here. I don't have the same manual as you. The manual I have mentions the communication cable as a "4 conductor telephone cable", but it then goes on to show that the terminals must be flipped.

I looked into this and found confusion on the subject of flipped or "reverse" and straight cables as it relates to phone vs. data service.

I thought I would simplify the issue by plugging into the cable as it comes out of the Air Conditioner. This way I'm using their cable and not introducing any other cable or adapter. Their cable (two cables, actually) are plugged into the power box and dangle out about a foot from the AC unit. I thought for sure using their cable would do the trick.

In the morning I'll do the next step and test the two center wires on that cable with my little jack. I'll see if maybe the 12v is there but coming out reversed and now requires another reversal in the form of an extension (possibly a normal phone line extension?) to the final location of the T-Stat.

Thanks very much for your research. Could you please send me to the 18 page manual you found? I have two manuals, but not the one you refer to. Really appreciate your help.

[Civilguy]

Originally Posted by Nik

Could you please send me to the 18 page manual you found? I have two manuals, but not the one you refer to. Really appreciate your help.

https://www.dometic.com/en-us/us/sup...uin-ii-_-20681

It's the second link on this page under "Manuals Download"; let me know if that works.

[Nik]

Success!

Mike, you pointed me in the right direction. Thanks.

I determined that the hot wire in the communication cable coming from the unit is green and not the red one. I reversed them through my electron gauntlet of multiple old phone jacks and splitters.

The T Stat now gets the polarity it wants - the reverse of what's coming out of the AC Unit and lights right up.


I still don't know what type of cable to use as an extension.

[Civilguy]

Here's a screen capture of the cables from the Dometic manual.

[Nik]

Oh yeah, that diagram I've seen. I'm ordering that same "straight" cable.

When ordering the female to female coupler there's plenty of comments about how one is straight and another crossed over, but again there's contradictions. I'm ordering a few to cover my bases.

It's pretty exciting that I got it to light up. And frustrating to wait till the parts come to see if it'll fire up.

Thanks again.

[Jon Vermilye]

Originally Posted by Nik

Oh yeah, that diagram I've seen. I'm ordering that same "straight" cable.

When ordering the female to female coupler there's plenty of comments about how one is straight and another crossed over, but again there's contradictions. I'm ordering a few to cover my bases.

It's pretty exciting that I got it to light up. And frustrating to wait till the parts come to see if it'll fire up.

Thanks again.

I do wonder why since the phone industry at least by volume, established the polarity of phone cables using the RJ11 connector. A number of other uses of the RJ11 decided to reverse the polarity from the phone company standard. It does make wiring things like inverter remotes, battery monitors, etc, interesting...

[Jon Vermilye]

Originally Posted by Nik

Oh yeah, that diagram I've seen. I'm ordering that same "straight" cable.

When ordering the female to female coupler there's plenty of comments about how one is straight and another crossed over, but again there's contradictions. I'm ordering a few to cover my bases.

It's pretty exciting that I got it to light up. And frustrating to wait till the parts come to see if it'll fire up.

Thanks again.

I do wonder why since the phone industry at least by volume, established the polarity of phone cables using the RJ11 connector. A number of other uses of the RJ11 decided to reverse the polarity from the phone company standard. It does make wiring things like inverter remotes, battery monitors, etc, interesting...

Of course the computer industry didn't do any better with the RJ45, and even ZAMP managed to reverse the standard for SAE connectors.

[Nik]

Agreed, cables and connectors in this realm are pretty messy. I can't believe I had to order phone cable! I used to have boxes full. I just hope they actually come with four wires!

[Civilguy]

Standards, standards, standards...

I've recently started assembling a build list to update my desktop PC after several years and it's definitely a whole new ball game.

[Nik]

As I was digging for phone cables I found all kinds of old computer cables. Very old firewire. SCSI cable, even. Wall block chargers, etc. Everything except simple phone line!
I'm not going to throw anything out!

I just pulled out a DVD/VHS deck. A great machine that records from one to the other. The cables? Only RCA. Luckily I have a ton.

[ThomasC]

Originally Posted by Civilguy

Standards, standards, standards...

I've recently started assembling a build list to update my desktop PC after several years and it's definitely a whole new ball game.

I spiffed up my two Ivybridge units last year with some eBay bargains because I didn't want to spend the money on new stuff. I also have a Surface 3 LTE that I use in my camper for my entertainment system.

The Surface 3 was getting tired. It was never that good because of the Atom processor so I bought a new Surface Pro X that has a Qualcomm processor. Wow what a unit it can run two 4K monitors at the same time and it finds cell service where my other things don't. I may never build another PC.

[Civilguy]

Originally Posted by ThomasC

I spiffed up my two Ivybridge units last year with some eBay bargains because I didn't want to spend the money on new stuff. I also have a Surface 3 LTE that I use in my camper for my entertainment system.

The Surface 3 was getting tired. It was never that good because of the Atom processor so I bought a new Surface Pro X that has a Qualcomm processor. Wow what a unit it can run two 4K monitors at the same time and it finds cell service where my other things don't. I may never build another PC.

Other than hard drives, I've typically bought mid-range, ho-hum hardware when I updated my desktop as I primarily ran business applications. Now that I'm retiring and closing the business, I started looking at the new Dell XPS 13 with 32GB of ram. I started getting pretty excited about that little gem.

Then I thought about traveling, in the trailer or otherwise; I'd like to take something I wouldn't mind losing or ruining. I realized the five-year-old, non-touch screen XPS-13 that I bought used a few years ago is perfect for the job.

Then I looked at the desktop case and realized I should just rebuild it again as it's gone pretty stale since 2014 or so. The last interim upgrade was doubling the memory and putting in a used processor from eBay.

So, as much as I'd like to have that awesome sleek, do-anything-go-anywhere machine, I think I'll keep the snappy new hardware locked up in the house here.

At least that's what I think I think right now.

[Nik]

Just to update: I got the AC Unit connected with its communication cable and am able to follow instructions to 'init' the T Stat.

There are four potential zones. 2,3 and 4 have dip switches. They are all set to off. After init the T Stat display flashes zone 1. And zone 4 is static. In other words the number 1 blinks and the spaces where two and three would be are blank and number 4 is showing steady.
This state is unchangeable.
Pressing the zone button repeatedly doesn't change anything. No effect. Re-init = no effect.

One note: When the T Stat first went on it read "FURN" as one of the modes. In fact Furnace was the only dip switch on. I turned it off. "FURN" stopped appearing. I flipped its dip switch back on. No effect. No "FURN" in the read out.
Any and all dip switch changes (since the initial turning off of the furnace) have no effect on the read out at all.
I paid $200 for this AC Unit. I've not been ripped off since the 1980s. I'm not inclined to chase down the guy I bought it from. The local RV shop can look at it on June 15th, if I like. I am more inclined to cut my losses, sell the T Stat cheap on ebay where I see them listed for 30% over retail (who buys them for that price?).

I imagine a new board will cost more than a good used unit purchased from someone with some integrity.

Anyone recommend the best quality 13,500btu units?