Duo-Therm Control Panel not working - maybe

[Pat]

Today I turned on the air conditioner at the Duo-Therm Control Panel.  It worked ok.  After an hour or so, I noticed that the compressor would click on and then click off in about 5 seconds.  Fan continued to run.  It was set on low.  I tried turning the temp down to keep the compressor on, but that didn't help.  I tried turning off the Control Panel and then back on, but that didn't help.  I turned the fan on high, which didn't help.  Eventually, the compressor clicks quit occurring, too.  I read the manual.  It says the air conditioner needs two minutes before the compressor will kick on.  I read the Control Panel manual, and that showed how to pop off the cover.  Underneath is a single RJ11 plug.  I pushed in the plug.  I took the stuff out of the cupboard and didn't see where the plug had any tension on it.  Still, no air.  Fan, but no cooling.  I popped the Control Panel cover off again, unplugged the RJ11 jack and replugged it in.  No compressor.  So Missy the cat and I sat in 5 hours of afternoon heat.  Then I tried it again and sat for two full minutes waiting to see if the compressor would kick on.  I had the temp set very low - 63 or something - to make sure it would attempt to cool.  After about 2 1/2 minutes I got up to turn it off, and the compressor kicked ON.  And stayed on for a minute or two. 

Recently I read in "Motorhome" or one of those magazines about someone else having this problem.  One of the suggested explanations was that something  had interfered with the RF of the Control Panel.  I wonder if completely unplugging and replugging fixed this.  This control panel runs the air, heat pump, fan, and furnace.  The furnace ran fine this morning. 

Any suggestions?  If it is the control panel, is there a reason everything seems to be working except the compressor?  I suppose I should try the furnace again to see if that's working.  I'll experiment with these things tomorrow, but I don't want to start something else going wrong at 10pm. 

--pat

 

[John From Detroit]

It is entierly possible that your control panel and control electronics are working perfectly Pat, it's highly unlikely that anytihng is interfering with the "RF" as it's unlikely the panel is RF.

What you have described is a classic motor overload, normally caused by one of three things on an air conditioner

1: Over charge (Solution, have an EXPERT check it out)

2: Siezed compressor shaft (Solution, Have an EXPERT check it out and replace the compressor)

3: Burned out compressor motor (Solution, same as 2)

Note in all cases the "Have an expert" part

If it's one of the above what is happening is the motor gets power... It can't turn so it quickly overheats, this trips the tehermal safety breaker within the motor's housing, It cools a bit, the breaker closes and the cycle starts over... Eveuntally the breaker itself is destroyed and then you get Nothing, Nothing, Nothing.

As I said, sure what it sounds like to me...

This does not, however, rule out other failure modes which can mimic the same symptom

 

[Pat]

JID:? The Duo-Therm is running the furnace fine this morning, so I'm afraid you may be right about the air conditioner having the problem.? I haven't really used the a/c that much in the 3 or 4 years I've lived in here.? Shouldn't have fried so quickly.? ?The a/c worked okay for the couple minutes I left it on last night.? I'll try it again this afternoon.? Then I guess it's off to the vet.? Unfortunately we're heading into a weekend, so I imagine I can expect a few warm days until I can get it looked at.?

What's "Over charge" mean?


--pat

 

[Gary RV_Wizard]

Unfortunately, John's diagnosis is likely to be right on the mark.  Since you have seldom used the a/c, there is a good chance the compressor motor has seized (rusted in place) and cannot start.  Sometimes an a/c technician can free it up, but  often it needs replacement (Ouch!).  In any event, you need to get it to an a/c repair shop or find a mobile service that will come to you.

There is zero chance that the Control Panel has anything to do with the problem.  If you hear the compressor trying to start, the Control Panel has done its thing and it is the a/c itself that is failing.

Sorry to be the bearer of such bad news...

 

[Pat]

I might have understated the amount of my use.  I run the air conditioner for maybe 4 or 5 hours every day here.  I use the heat pump occasionally, too, to make sure those parts are working. 

Much to my relief, the little sucker worked fine all this afternoon.  So, I'm thinking praying helped. 

Would inadequate campground power make a difference?  I'm next to some really heavy duty users, and when they're home, my voltage readout goes down to 107 or 108 when the compressor kicks on.  Normally it's around 112 to 113.  Voltate when it wasn't staying on yesterday was 113. 

What exactly does the RJ11 jackand wire  in the control center do?

--pat

 

[John From Detroit]

I might have understated the amount of my use.? I run the air conditioner for maybe 4 or 5 hours every day here.? I use the heat pump occasionally, too, to make sure those parts are working.?

Much to my relief, the little sucker worked fine all this afternoon.? So, I'm thinking praying helped.?

Would inadequate campground power make a difference?? I'm next to some really heavy duty users, and when they're home, my voltage readout goes down to 107 or 108 when the compressor kicks on.? Normally it's around 112 to 113.? Voltate when it wasn't staying on yesterday was 113.?

What exactly does the RJ11 jackand wire? in the control center do?

--pat

Yes, low voltage will also cause the symptoms you cited.

What does teh RJ11 jack and wire do... Carries the control signals to the unit from the control center and power from the unit to the control center.  Standard theromostat setup.  That is why I said RF interference was not likely the culprit, no RF, it is a wired unit.  That is your "Thermostat wire"

 

[Pat]

JID:  Thanks for the last two points.  Goes to show I don't remember what the article said.  Is it at all possible that a slightly separated RJ11 connection would cause the temporary on/off condition I experienced with the compressor the other day?  I really hope so, because unplugging and replugging the thing exhausted my technical expertise. 

JID and Gary:  Please be assured that I never fix things that I shouldn't.  I'm terrified of fire and gas or anything combustible.  I never use my cooktop, because I don't want an open flame in here.  So far the things I've fixed have been within an RV owner's usual maintenance tasks, such as changing the holding tank valve.  The work on the furnace was part of normal maintenance that I got out of the manual.  Turned out that did the job; otherwise, I'd have had to get a professional to fix it.  Lucky break.  I've had about 5 things go wrong this summer.  The original converter was admittedly a piece of bad engineering.  The new one is a dream. 

One of the most important purposes of this forum is for people like me to avoid ignorant and/or malicious advice from supposed professionals in the repair industry.  I've gotten plenty of both.  You need to know the answers in advance before asking for repair work.  In a forum like this people have no financial interest in selling merchandise or work that I don't need.  They are also informed.  If somebody is wrong, there are 3 or 4 others ready to jump in with gentle suggestions that the correct solution could lie elsewhere.  Right now I'm fascinated by the discussion on AZ hard water treatment.  It has evolved into what I think will be the best solution, and I have even found a couple products that may work.

I bought an extended warranty for the first time, just before I left AZ in May.  I didn't realize the deductible is applicable to the entire year.  I thought it was per occurrence for every single repair, so I have been paying for everything out of pocket and trying to fix what I could myself.  Having reread the insurance contract, I see that it's worded that the deductible is an annual thing.  Fortunately, except for the converter, I haven't spent more than about $100.  Unfortunately, this summer is the only one in my life where my income is half what it would be, as I transition from pension supplement to social security.  Naturally everything in here knows that and starts acting up. 

--pat

 

[John From Detroit]

JID:  Thanks for the last two points.  Goes to show I don't remember what the article said.  Is it at all possible that a slightly separated RJ11 connection would cause the temporary on/off condition I experienced with the compressor the other day?  I really hope so, because unplugging and replugging the thing exhausted my technical expertise. 

Possible, yes, but probility is very very close to zero,  It's most likely a low voltage situtation from what you said.

Monitor voltage, if it goes too low fire up the genset and complain to park management

 

[Karl]

Hmmmmm...........  Was the question ever asked: "Does it work properly when running the genset?" If you have a 2kW genset, that should be plenty for 1 a/c unit; a 1kW genset would be marginal at best or not work at all. If it works with the genset, your problem is most likely low power at the site.

 

[Pat]

A while ago the voltage read 109.  That's the lowest it's been today.  I've seen 107 on a couple days.  Most of the time it's 112 or so.  This is with the compressor running.  Voltage goes up 3 or 4 volts when the compressor cycles off.

What seems to have fixed the problem was to reset the Duo-Therm by unplugging and then replugging the RJ11 jack.  One of the first things I tried was pushing the plug in tight enough, and that had no effect.  A complete unplug must have caused some kind of reset. 

We're in a weekend heat wave up to 94, so I'm really glad this thing is working.  At least I don't have to shave the cat.

Since it's working, I can't comparison test it with the Genset, but during the last monthly exercise thereof, I ran the air conditioner to put a half load on the generator, and it was fine.  Volts are always better with the 4k generator than with the campground.  The family next door and their friends next to them have been away all weekend, so maybe when they return and fire up their equipment I'll have problems again.  Then it's time to talk to management.  My monitor says anything 105 and above is acceptable.

I hate to run the fridge on LP in this heat.  Would it help, or would I just be providing more power for the neighbors?

--pat

 

[Karl]

Anything you can do inside to reduce power consumption will benefit you AND your neighbors. Make sure your power cord is not part of the problem. If possible, don't use extensions because this will increase the resistance and lower available power to your rig. If you are using extensions, you should be using heavy-duty ones made for RV's; not just those so-called heavy-duty extension cords you can get at Home Depot or the like. They just aren't big enough (wire size). Feel the plug. If it is hot, chances are that it is not making good contact inside the plug or with the receptacle - another cause of low power. Take the plug apart and clean away all corrosion. There may be corrosion in the receptacle box too. Have the campground owner check and clean it. Refrigerators can run a long, long time on a little propane. Depending onwhere you are, it may even be cheaper than running on electricity. I'm not sure how your monitor can make a general statement the "Anything 105 iand above is acceptable". Geneerally, that MAY be true, but it doesn't take into account that motor bearings, in particular, can run dry and require more power to run than one that is properly lubricated. Unfortunately, an a/c compressor is a sealed unit and there's no way to lubricate it, but a load test should would tell if there is a problem - but that's not something you can do; a technician would be needed to run that test. 

 

[Pat]

Karl:  You're a mind reader.  I was just about to ask the effect of removing the 25' extension cord from my power cord.  Generally when I'm hooked up for months, I like to use my RV-specific, heavy duty, 30amp extension cord and not expose my 25' built-in cord to the elements.  Today I removed the extension, and I think I picked up a volt or two.  No more, but something. 

I always close power post boxes that people lazily leave open.  No need to add more dirt to those plugs. 

Would it make any difference to plug into a 30amp to 50amp adapter and connect the 50amp plug in a power post?  My unit is 30amp as noted. 

Also, is it or isn't it true that nearby power users could affect the amount of power available to me?  People keep telling me that neighbors' use can't affect the 30amp available to me via my post.  I tell them that a certain amount of power is allocated by whatever central source is feeding our power posts, and if there is too much usage by the individuals added together, the posts won't get the full amount of power indicated.  I'm saying this clumsily, but I hope the meaning is sort of apparent.  So, if the guy next door, and his inlaws next to him return from out of town and fire up their air conditioners, might I notice a change in available volts?

--pat

 

[John From Detroit]

Would it make any difference to plug into a 30amp to 50amp adapter and connect the 50amp plug in a power post?? My unit is 30amp as noted.?

Likely no, depends on the camp ground but likely no

Also, is it or isn't it true that nearby power users could affect the amount of power available to me?? People keep telling me that neighbors' use can't affect the 30amp available to me via my post.? I tell them that a certain amount of power is allocated by whatever central source is feeding our power posts, and if there is too much usage by the individuals added together, the posts won't get the full amount of power indicated.? I'm saying this clumsily, but I hope the meaning is sort of apparent.? So, if the guy next door, and his inlaws next to him return from out of town and fire up their air conditioners, might I notice a change in available volts?

Now this is a tougher one... The answer is campground dependent.

Some campgrounds are set up so sections of the camp ground are all on the same circuit, for example, one CG I was at recently all the campign sites on one side of the road were on one 100 amp circuit (the other side of the road had another circuit also 100 amp) each site had 20/30 amp boxes but there was only 200 amp (divided) for the entire facility (Small, perhaps 10 sites per side of the drive 20 total)

Now they used good heavy wire, but if too many folks ran AC, you suddenly got zero amp service

Some campgrounds use wire that is far too small for the sites they service,  Now if there are a lot of tent campers running a television or radio and perhaps a lamp, no problem... But if you have a bunch of 30 amp loads (or 50's) it can quickly start to see brownout voltages (What your have)

Fifty amp service is a different animal entirely since it's 240 volt split phase (120-0-120)

Now to do it right you use some very good wire from the main power panel in the park to each sub panel, then at least 10 ga or heaver for 30 amp service and still heaver wire for 50 amp service. (Note this assumes copper wire, heaver still if it's aluminium, which was used some years back) and heaver for longer runs (to reduce voltage drop)

Now, aluminum wire, there is another can of worms.  Where aluminum wire joins the copper in the box there is a mis-matched metal juntion,  This can be fairly reliable but it needs to be inspected regulary, and you need to use special procedures or fixtures as well  Most campgrounds wired with Aluminum were done before I was born, the current management has no clue as to how to maintain the wireing and may well not even know that it's not copper.  Thus bad things happen..  Then there is the power transformer feeding the park,,, It too can be too small.

Side note: One campground I visit all the time,  the main power transformer that feeds the park fried, The power company put in a "Temporary" replacement till they could get a proper sized replacement in (about 1/3 the physical size of the original) this worked, sort-of, for some  years (Temporary appearantly means something different to Consumers power and myself) till the the main 120/240 lines from the transformer to the main distribution panel went up in smoke (They were indeed aluminum)  Well, as it happens the park manager was a licensed electrician, he replaced the old wire (all 3 legs) with brand new, heaver guage, copper wire.

Within six months the temporary transformer blew

The power company finally brought out a proper transformer.. Which they hooked up wrong..

So instead of 120-0-120 they had 120-120-0,  This means half the park had 240 volts where 120 belonged

or, in short POP goes the microwave, tv, radio, power converter and other electronics.

 

[Pat]

JID:  VERY interesting.  I've copied and saved for future reference.  I love stuff like this. 

I think this campground is new enough to have copper wires, but I'm not sure about gauge and whether there's enough power to go around.  I do know that the folks got home next door, went inside, and probably turned up the air, etc., because my available volts dropped by two.  Timing was too exact to be coincidence, and this isn't the first time I've watched it happen.  Things will get worse when the trailer next to them is also occupied later this week and and least all of next.  The guy next to me has his 50amp plugged in plus a 110 extension going to a truck camper he's been permitted to park in front of him temporarily.  I don't think they realized he was going to run another power cord.  When all of them were going the other day, and my compressor was running, my available volts went down to 107.  Our side of the park has to be inadequately powered, because someone on the other side says his available volts stay above 112, regardless of how much air he's running or how many big rigs surround him.  We in a sort of isolated little section with only 5 spots. 

The transformer near the park had to be replaced a couple weeks ago when somebody hit it with a car.  I think they just ran a temporary line across the river from another transformer. The bigger side of the park was having power outages a few days before that, but apparently it's been fixed. 

I have been speaking with the woman who runs the office, but I will talk with the owner now that they're back from a short trip.

--pat

 

[middle.american]

In case someone else has a Duo-Therm suddenly not working and finds this topic....

The last time my Duo-therm suddenly "did nothing" it was merely a blown fuse in the unit. I took the plastic cover off, took the galvanized cover off and changed the car style fuse. I read that low voltage can blow a fuse. In any case, if your Duo-Therm suddenly doesn't do anything check this little $1 fuse before calling in the big guns.

 

[fredethomas]

Make sure your AC voltage is good.  125 to 122 volts or such.  I think the cut out is about 108 VAC.  But if the input lines are too small - there will be a voltage drop that goes below the A/C's tolerance level.  Read the input voltage as you start the unit.