Dometic Analog Control Board Needed

[shepardmike]

Hello,

I have a situation where my interface to my AC is analog. Forest River Berkshire 34QS 2019. There are CAT5 cables that run to a box built by Precision that converts the digital signal to analog. So the T-STAT is controlled by the Precision Plex and the wires coming out of the Digital/Analog converter are AFH, AFL, COMP, AHT and GND. They had a cable that went into the control relay board up in the AC, and I am assuming they tied into those wires to control the unit, fan low, fan high, compressor, heat etc.

So the AC failed and even though it was built in 2017 Dometic still made the same unit Penguin II which I then purchased. When it arrived it didn't have the control relay board. I called Dometic and got the part # and ordered it. When I got it, it turns out that it's Digital. The only external connections are +12 V to T-STAT, +12 From Supply, -12V from Supply and to T-STAT, and COMM.

I got the original part number (3106997.004) of the control board off an old picture and called Dometic. They said they don't make it anymore and I searched high and low and all the shops show it's discontinued. There is just the relay board on Amazon but I need the whole kit, cables and metal box.

Unfortunately the old AC and control board are probably already recycled.

What are my options?

[Krbjmpr]

If you can find the actual analog relay board, that is going to be the biggest task. Those are getting pretty rare, not as rare as the linear thermostats, and even rarer are Heat Pump thermostats...


Please post pics / model number of that digital / analog adapter. I don't think that I have seen it before, or maybe I have and didn't realize as thought was part of Firefly / Spyder / etc.



If it were me, I would order the relay board off amazon. Make sure that you get at least a 30day warranty (through Amazon). Seller might offer better. You will need the freeze sensor for that particular control box as well.



As far as the thermostat goes, just use a battery thermostat from Walmart or similar. If memory serves, Rc is 12v, Then you have your furnace, fan, compressor terminals, perhaps heatpump. As far as wiring goes, you should be able to use whatever is there already. Most units will use CAT4 (phone line, 2 pairs) or T-stat wiring (5 or 7 wires).


The only gotcha on using the residential thermostat is that you will lose a fan speed. Usually people who convert will wire it as High Only, and maybe add a switch to flip between high and low manually.


If you dont need heat pump, I did find an after market dometic replacement thermostat at amazon.


https://a.co/d/1sOHiSU


Hey, its your lucky day! Actual Dometic Analog T-Stat

https://a.co/d/9hwRRsC


Again, use the existing wiring, I believe you said it was CAT6.

[shepardmike]

Krbjmpr - thanks for your input.

This is the Digital /Analog converter - https://i0.wp.com/www.precisioncircu...-10058-000.png

2 CAT5 connections

I did get the control board but it doesn't have any plugs or wires attached to it. I need the metal box, the plug connectors, the whole kit.

If you look at the attached photo, there are 4 wires coming out of the CB, blue, yellow, green and brown, that goes into a plug/connector. The Precision D/A plugs into that.

Google hasn't turned up that kit, just the board inside. Any suggestions on who to call as far as RV parts suppliers?

[Krbjmpr]

Ah, now I understand.

You bought a replacement PCB that would normally go inside the 3106997.004 Control / Relay box.


Hate to say this, but you are going to be pissing in the wind trying to create / build what you need. Buying the molex to match that pcb in 1-off quantities are going to be relatively expensive, then you will need crimpers to crimp the sockets onto the ends of the wire before they are set into the backshells.


Honestly, you would be better off going to the RV Dealers around you. Talk to someone in the service shop, let them know that you are looking for an Analog Control Relay box, 3106997.004 and will put a $50 bounty on it. I have yet to come across any dealer that didn't have a parts hoarder who preferred to keep all the old take-offs.


The replacement PCB that you currently have in your possession is probably going to be used once you find a Control Relay box. Dometic Analog t-stats were the cats meow, many wish they never upgraded to the digital. One of the notable features is that when the analog t-stat begin to fail (resistor temperature set strip), it would kick on the compressor off and on rapidly. This caused the compressor relay to burn up, necessitating replacement of the PCB. Since RV Techs are by and far lazy (myself included), they didn't argue with parts department when the assembly was ordered, not just the PCB.


Taking this a different direction...
You *ARE* able to use one of the newer Dometic digital thermostats. As long as you have 3 wires (for 3 button) or 4 wires (10/11/12 button), you can install one. 3 wire (square one that everybody and myself bitch about) will be screw terminals under the tstat cover, and wire nuts up in the adb. 4 Wire will require phone jack housings, so you can get to RJ12 connector and then to the t-stat, and relay box. Yup, at both ends.


The digital variety will not work with your existing system, but your existing system can work around it. You would lose central control of one of your air conditioning zones, and it will have its own tstat installed wherever you deem fit / will fit.



If you can't find a relay control box near you, try giving Colaws RV Salvage a visit at Colaws RV Salvage. Do NOT hesitate to install as their return policy leaves a lot to be desired. You might even contact the dealer / mobile tech that did the change and ask if they still have the relay box from your old unit. See hoarder statement above.



If Colaws, or any other cant help, send me a PM. I would be shocked if I don't have any more of those assemblies. Yeah, I am one of the hoarders I mentioned above.


Incidentally, I was wrong on previous description using residential tstat. Dometic function wires are grounded to engage.