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StrokerAce · 04-29-2012, 07:22 AM

Well folks here we go again with the ongoing story of the A/C problem. And you have REALLY got to be kidding me on this one. Hope I can get all this in. As you can see from earlier post I have changed the "Hard Start Kit" and even Bypassed the "Overload Protector". I had even gotten brave and opened up the "Control Box" that has the relay board in it and checked the 3 amp fuse this is in it. After much talking with the local RV dealer that I bought the camper from I dug a little deeper. Had to go online to find the wiring diagram for the control box. And after looking at it I found the "K6 relay" that provides 120V that goes to the compressor. After checking that I found that the "K6" relay that supplies power to the compressor was not letting 120V's go through to the compressor! Wonderful! I had found the problem. So I called up the loacl RV dealer and gave him the number of the "Control Box" and he had one. Only $118.00 after taxes and it came with a new analog thermastat. Good! I think that mine was acting funny anyway. But thats another story. Happy as I could be I installed the new "Analog Control" as it is called with the new thermastat. Might as well go all the way with it. Now for those of you who have ever been in one of these know that the "Black" wire coming in supplies 120V of power to the "K6" relay that feeds the compressor and the "Blue wire" that comes out goes to the compressor and that starts the compressor. Now somewhere in all of this, there is a signal somewhere from the thermastat the is suppose to "trigger" the "K6" relay to open to supply 120VAC to the compressor. So after installing all of this I am ready to give it a go! And to my wonderful suprize when I turn the A/C on...................IT STIL DIDN'T WORK!!!! Can you believe that! So I started checking all the wires. All hooked right and everything. BUT....and here we go again.....power that comes into the "K6" relay is still not coming out the otherside of it. So I think that it might be the wiring from the "thermastat" to the "control box" so off I go back to the RV dealer to tell him that. After getting there and talking about it, and now he is scratching his head to, we think that it might be the thermastat wiring. So I change that. And still no power coming out of the relay! I didn't run the wire through the camper yet just wanted to hook it up and see if it would work. Now the rest of the story. One of the "techs" there said to check the "voltage" readings at the thermastat and that there should be around "7 volts DC" reading on the "yellow" wire when A/C is command on. Well there isn't. Now I wrote down how the wires were installed on the old thermastat and installed it the same way. The only way the I can get voltage to the "yellow" wire is to not turn the A/C on. Right now there is 8.27 volts to the "yellow" hookup at the thermastat. When you turn the A/C on it goes down to "0.01" volts and the output voltage from the "K6" relay is 0.07 VAC. And the thermastat is turned dowm to 60 degrees. Readings acrossed the thermastat without the A/C on are as follows.
+7.5 "Red" 7.65 A/C on 7.57
Cool "Yel" 8.27 A/C on 0.01
Fur "Wht" 19.36 A/C on 18.66
Hi Fan "Blu" 19.32 A/C on 18.67
Fan "Brn" 19.32 A/C on 0.07
Gnd "Grn" .003 A/C on .009

So what do you all think? Thanks again for all of you that have responed to me. Maybe this will help someone else.

StrokeAce

TXiceman · 04-29-2012, 07:29 AM

StokerAce, it is baffling to me. I wish I was not so far away. Best advice, since you have a wiring diagram is to go back to the start and check each wire fro the proper signal.

Ken

StrokerAce · 04-29-2012, 08:44 AM

I would if I could find what the proper signal is suppose to be at the thermastat. Is what I wrote in my message the right readings? And does everything that I have done sound right or did I make a mistake somewhere? And thanks for the kickback on my post.

StrokerAce · 04-29-2012, 10:08 AM

Sorry about wrong info on last msg. I said that it was the "K6" on the circuit board and it should have been "K4". Don't know where I came up with that one. Hope it didn't confuse anyone.

StrokerAce · 04-29-2012, 03:14 PM

Quote:

Originally Posted by StrokerAce

Didn't get a chance to work on it last week because of work. But did find a wiring schematic online when I went to "Duo Therm A/C by Dometic" and found it. I think that it's the blue/white stripe. But will checkand let you all know. Just wondering if I might be wasting my time and the A/C unit is bad. But with the prices of "units" and what what shop labor is, you are looking at a big slice of your paycheck to get it looked at and new one installed. Good old shade tree mechanic's is what I say! LOL! Will let you know what I find.

StrokerAce

Yea Jim I just seen your quote" from yesterday. If you seen my "BIG" message, you seee where that 120V is not coming out of the control box. Someone on here told me or seen it somewhere about a website that had the whole manual for Duo Therm. I went there and it is 126 pages long with a lot of good info. Went through it and got some readings and getting ready to go out and see what I can make of it. Man is this getting touff! LOL! Though owning a camper was suppose to be "FUN"! I guess thats only when they work right, huh? LOL!

StrokerAce · 05-04-2012, 01:13 PM

We campers.....StrokerAce here. Have been busy at work so have not had time to work on A/C problem. Ordered a "Run Capacitor" and installed it just a minute ago. So now that I have checkout all the parts in this system and all check as per the service manual I found for Duo Therm units. So from the thermastat to the over load protector and the compressor wiring checks good.
So I just installed the run compressor and reconnected the 12v to the thermastat and turned on and checked the 120v feed into the control box that is brand new also as well as the hard start kit and new thermastat wire and lo and behold guess what happen?
THE SAME THING AS BEFORE! YOU HAVE GOT TO BE KIDDING ME! STILL NOT GETTING 120V TO THE OTHER SIDE OF THE RELAY IN THE CONTROL BOX! The odd thing is that I have 8.73v on the "yellow" wire in the thermastat that is suppose to supply power I guess to the control box circuit board to energize the relay and let 120v go to the compressor but as soon as you turn the A/C switch to "cool" on the thermastat that voltage goes to 0.06v. So I am totally lost now! HELP ME! I'M DROWNING HERE!

StrokerAce
Lost in Florida's A/C world!

Rikmac · 05-04-2012, 01:56 PM

Just a thought, have you put a set of gauges to check the freon pressure? If you have too low of a pressure the compressor will not kick on. I remember a few years ago this happening to a friend and when he added some freon all started working as normal.

jlfbatonrg · 05-04-2012, 07:18 PM

StrokerAce,

Two things concern me a bit, first shouldn't the red feed wire have 12V on it?
Second the yellow wire voltage drops to 0 when activated. It would seem possible you might have a bad ground coming to the thermostat. Check to be sure the ground wire is solid. If not try to make it solid.

Jim

StrokerAce · 05-05-2012, 12:09 AM

Quote:

Originally Posted by Rikmac

Just a thought, have you put a set of gauges to check the freon pressure? If you have too low of a pressure the compressor will not kick on. I remember a few years ago this happening to a friend and when he added some freon all started working as normal.

This unit is a sealed unit and cannot be serviced. I have seen no trace's of a freon leak anywhere. If there was there would be some sort of oil residue where it was leaking.

StrokerAce · 05-05-2012, 12:42 AM

Quote:

Originally Posted by jlfbatonrg

StrokerAce,

Two things concern me a bit, first shouldn't the red feed wire have 12V on it?
Second the yellow wire voltage drops to 0 when activated. It would seem possible you might have a bad ground coming to the thermostat. Check to be sure the ground wire is solid. If not try to make it solid.

Jim

Yea Jim there is 12v. Lost all of last reply so have to start over. Ground seems to be ok but will check again though. The service manager at the RV dealer where I bought the camper said that there should be no voltage on the "yellow" hookup in the thermastat until you select "Cool" on the thermastat, then it is suppose to supply 7.75v through the "yellow" wire to the control box and open the "K4" relay and hold it open and let 120v go to the compressor. I have voltage on that "lead" on the thermastart board and I shouldn't have and I don't know why? He said that something might be "shorted" somewhere that might be causeing that. But all that is left to the 12v supply wire that is coming from the batteries? Don't know how to check that? If you want, I can see if if there is someway that I can email or somehow send you the website of the manual that I am useing. I really think that it is something simple but this last time I went down to the dealer another service person I was talking to said that I should bring it in to have them check it out. Thats $114.00 and hour! I don't have but $150.00 in parts so far and think I'm doing about as good? LOL! Plus I could have another whole unit shipped in here from Texas for about $529.00 with shipping from PPL. You have been a great help so far, thanks. Just don't know where I am at now?

StrokerAce · 05-05-2012, 12:37 PM

Hope this works. if not try this Jim.
http://bryantrv.com/docs/acservice.pdf

StrokerAce · 05-05-2012, 05:41 PM

Hey Jim. Went and checked the compressor again and my reading were as followed.
Common-Start .002 ohms
Run-start .003 ohms
Common-Run .000
You think that, that little of resistents is enough to cause the compressor to not start? it says in the check "Lack of continuity between any of the terminals indicates faulty wirings in the compressor, and the compressor should be replaced".

StrokerAce · 05-06-2012, 10:56 AM

Here is one of the odd things. With the plug that goes up to the roof unit is unplugged and checking voltages, the yellow wire on the thermastat that has 8.73 volts that is suppose to let 120v go through the relay that supplies voltage to the compressor, voltage goes away. So it is doing the same thing with the roof unit plugged in or not plugged in. Odd?