Free 7 Day Trial RV GPS App RV Trip Planner Campground Reviews RV Maintenance Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Monaco Owner's Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 07-24-2021, 05:53 PM   #1
Member
 
Join Date: Jul 2017
Posts: 59
Did I kill the A/C thermostat?

Ok, my AC units are just slightly older than God, but they have never given me an ounce of trouble. Just came back from a 2000 km trip and they worked flawlessly with our genset and also 50A power at a campground.


Went to plug in at home for the first time on our 30A garage plug only to discover that it was 30A but 240v. Ug.


Quickly unplugged and checked out the RV and surprisingly EVERYTHING but the AC units works. No blown fuses, and as far as I could tell only one breaker popped.



But the AC units wont operate. There is no power to the wall thermostat controller. And there's the problem. They are 1991 Dometic Duo Therm 806069042 and yeah, that's prehistoric but they are made in Japan, great quality and have worked fine til now.


I checked the AC fuses both 12v and 120v breakers. All good. Checked 120v power and its live right to the box inside the AC unit. But I dont know if there is any way to check the actual thermostat. It looks like this. Cant even find a pic of it online but did find some other people who converted to another controller but they started out with one newer than this. Trick is mine has 10 wire flat pin connector and most of the new ones have 6 or even 4. Not sure why so many wires when its just an AC unit, no heat pump, no furnace control.


Anyone got a clue how these connect? Does the 12v power for the thermostat come FROM the AC unit and down to the thermostat or does it come from the fuse box to the thermostat? Is there any way to check if its functioning.


Just kinda dont want to give up and maybe Im missing something that can get them functional again.
Attached Thumbnails
Click image for larger version

Name:	20210724_135818.jpg
Views:	14
Size:	102.6 KB
ID:	337098  
NorthOrSouth is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 07-24-2021, 06:12 PM   #2
Senior Member


 
Winnebago Owners Club
Join Date: Sep 2015
Posts: 1,085
Quote:
Originally Posted by NorthOrSouth View Post
Ok, my AC units are just slightly older than God, but they have never given me an ounce of trouble. Just came back from a 2000 km trip and they worked flawlessly with our genset and also 50A power at a campground.


Went to plug in at home for the first time on our 30A garage plug only to discover that it was 30A but 240v. Ug.


Quickly unplugged and checked out the RV and surprisingly EVERYTHING but the AC units works. No blown fuses, and as far as I could tell only one breaker popped.



But the AC units wont operate. There is no power to the wall thermostat controller. And there's the problem. They are 1991 Dometic Duo Therm 806069042 and yeah, that's prehistoric but they are made in Japan, great quality and have worked fine til now.


I checked the AC fuses both 12v and 120v breakers. All good. Checked 120v power and its live right to the box inside the AC unit. But I dont know if there is any way to check the actual thermostat. It looks like this. Cant even find a pic of it online but did find some other people who converted to another controller but they started out with one newer than this. Trick is mine has 10 wire flat pin connector and most of the new ones have 6 or even 4. Not sure why so many wires when its just an AC unit, no heat pump, no furnace control.


Anyone got a clue how these connect? Does the 12v power for the thermostat come FROM the AC unit and down to the thermostat or does it come from the fuse box to the thermostat? Is there any way to check if its functioning.


Just kinda dont want to give up and maybe Im missing something that can get them functional again.
You got lucky. Is it a 50 amp RV and you were using a dog one to connect to 30 amp? Not even sure how you could do tha as the 30 amp RV plug is way different than a 30 amp dryer or welder plug.

It sounds like you did not try to run anything on 240 volts.

Do you still have 12 power to everything else? The power converter/charger is normally always on. Could you have fried it?

If all other 12v is working but you have no 12v to the line in to the thermostat is it possible that even with the AC off something in your AC units blew. I think 12v goes to the AC control board, then down to the thermostat.
First thing you need to do is find out why you have no 12v coming into the thermostat. That may not have been what failed. If the thermostat was on, there may be a relay that is run by 12v but handles the 120 to theAC units.
__________________
2006 Winnebago Journey
39K
Cat C7
amosnandy is offline   Reply With Quote
Old 07-24-2021, 07:13 PM   #3
Member
 
Join Date: Jul 2017
Posts: 59
Quote:
Originally Posted by amosnandy View Post
You got lucky. Is it a 50 amp RV and you were using a dog one to connect to 30 amp? Not even sure how you could do tha as the 30 amp RV plug is way different than a 30 amp dryer or welder plug.

It sounds like you did not try to run anything on 240 volts.

Do you still have 12 power to everything else? The power converter/charger is normally always on. Could you have fried it?

If all other 12v is working but you have no 12v to the line in to the thermostat is it possible that even with the AC off something in your AC units blew. I think 12v goes to the AC control board, then down to the thermostat.
First thing you need to do is find out why you have no 12v coming into the thermostat. That may not have been what failed. If the thermostat was on, there may be a relay that is run by 12v but handles the 120 to theAC units.

Yeah its a 50A RV and I was using the adapter to connect to 30A. I did try to turn on the AC's when it was plugged in. I dont have the original converter/charger anymore so I have a 3000w inverter and a separate 10A battery charger for the house batteries. They both still work fine.


The AC was off, I switched it on for a second. Nothing. Then I noticed my voltage gauges were showing way off the scale past 120v and realized I was feeding the bus 240v and quickly unplugged it so its possible the ACs got a shot of 240v for sure. Wonder what part that would fry? I took off the control panel cover on the unit but nothing looks burnt and theres no visible fuse.


ps. Not that it matters now, but the reason that Nema TT-30 plug was wired for 240v was because I was using it to charge my EV and I wired the plug because that was the receptacle and plug that I happen to have handy, never thinking that I would use it for the RV. D'oh. I forgot it was 240v.
Attached Thumbnails
Click image for larger version

Name:	20210724_154805.jpg
Views:	13
Size:	224.1 KB
ID:	337109  
NorthOrSouth is offline   Reply With Quote
Old 07-24-2021, 07:15 PM   #4
Senior Member
 
Join Date: Jul 2014
Posts: 28,402
The thermostats often use 12 volt power from the heater circuit to power them.

That's where I would be looking.
twinboat is online now   Reply With Quote
Old 07-24-2021, 07:24 PM   #5
Senior Member
 
Join Date: Apr 2018
Posts: 1,648
If you used a 30 amp 220 dryer plug to a 50 it should not have done anything. If it had no neutral nothing could go back to complete the circuit. Did you make your own dogbone?
shootist is online now   Reply With Quote
Old 07-24-2021, 07:55 PM   #6
Member
 
Join Date: Jul 2017
Posts: 59
Quote:
Originally Posted by twinboat View Post
The thermostats often use 12 volt power from the heater circuit to power them.

That's where I would be looking.

The furnace did turn on when I tested it but didnt seem like it ignited. I shoved the thermostat all the way up but its a hot day. Have to try it tonight but I would think if the furnace blower works it has power even if the auto igniter isnt clicking.
NorthOrSouth is offline   Reply With Quote
Old 07-24-2021, 07:59 PM   #7
Member
 
Join Date: Jul 2017
Posts: 59
Quote:
Originally Posted by shootist View Post
If you used a 30 amp 220 dryer plug to a 50 it should not have done anything. If it had no neutral nothing could go back to complete the circuit. Did you make your own dogbone?

For the RV? No. Its a commercial one. 50A down to 30A dogbone.


The receptacle I wired had a black wire to one side and a red to the other side and a green to the ground but yeah, no white neutral was connected.
NorthOrSouth is offline   Reply With Quote
Old 07-24-2021, 08:15 PM   #8
Senior Member
 
RamiDav's Avatar
 
Join Date: Jan 2016
Posts: 1,731
Losing the neutral can fry or knock out lots of things. With 240 in the coach and no neutral coming in current can flow thru an A/C or other
high amp device thru some lesser amp electronics, they will see most
if not all of the 240v.
An open neutral on a 50a RV is a bad thing.
That is why I have a Progressive EMS HW50C to guard me against being
able to accidentally connecting to a bad pedestal and I recommend that
all other coach owners install one too.

http://https://www.amazon.com/Progre...57977890&psc=1
RamiDav is offline   Reply With Quote
Old 07-24-2021, 08:21 PM   #9
Senior Member
 
Join Date: Oct 2014
Posts: 3,376
Yup, you have "let the smoke" out of any 120 VAC item running when you plugged into a 240 VAC 30 amp outlet.


Check every 120 VAC device carefully-- either on a REAL 30 amp RV outlet or off the generator. Yes, you could also use a 15 amp shore power outlet with adapter (and limit what you run to under a 15 amp draw).
__________________
Brett Wolfe
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240
wolfe10 is online now   Reply With Quote
Old 07-24-2021, 09:02 PM   #10
Senior Member
 
Join Date: Apr 2018
Posts: 1,648
Still can't see any current being able to flow. Both legs are separate 120 in the rv. It would be like the old stuff wired hot and the switch completes the circuit to neutral. In this case there was no neutral. Something could have leaked, like capacitors I guess.
shootist is online now   Reply With Quote
Old 07-24-2021, 09:07 PM   #11
Senior Member
 
Join Date: Oct 2014
Posts: 3,376
What he plugged into had a HOT on the "RV hot" and a HOT on the "RV neutral".


That is 240 VAC to anything running when this happened.
__________________
Brett Wolfe
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240
wolfe10 is online now   Reply With Quote
Old 07-24-2021, 09:08 PM   #12
Senior Member
 
Join Date: Apr 2018
Posts: 1,648
Ok, he used a 120 dogbone. I get it now
shootist is online now   Reply With Quote
Old 07-24-2021, 09:13 PM   #13
Senior Member
 
Join Date: Oct 2014
Posts: 3,376
Quote:
Originally Posted by shootist View Post
Ok, he used a 120 dogbone. I get it now

OP: "Went to plug in at home for the first time on our 30A garage plug only to discover that it was 30A but 240v".
__________________
Brett Wolfe
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240
wolfe10 is online now   Reply With Quote
Old 07-24-2021, 09:29 PM   #14
Senior Member
 
RamiDav's Avatar
 
Join Date: Jan 2016
Posts: 1,731
If the neutral is missing then devices on leg 1 that are turned on will provide a path to any devices on leg 2 that are turned on.

Now if the loads on the 2 legs are balanced all would be fine.
However, realistically that is not likely.
A more likely case is an A/C on leg 1 and the TV on leg 2.
In that case, the A/C is for practical purposes a straight wire for the
TV to get a dose of 240v

Maybe not very clear but it's late for me, 10:30 and past my bedtime.
RamiDav is offline   Reply With Quote
Reply

Tags
thermostat



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Did my inverter kill my Wally? Campingkris Technology: Internet, TV, Satellite, Cell Phones, etc. 8 02-18-2021 08:45 AM
Did my rv kill my pepper tree? Radacravitz Just Conversation 8 06-14-2020 08:12 PM
Did I Kill my Water Pump? Dollie02 RV Systems & Appliances 13 11-08-2019 07:05 PM
Did I Kill My Battery? BigJohn1 Travel Trailer Discussion 7 05-14-2019 10:51 AM
Did I Kill My New House Water Pump Guardsman Class A Motorhome Discussions 10 08-17-2018 10:31 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 09:45 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.