Dying air conditioner?

[StarDancer]

I'm told I need a new air conditioner by my new RV tech.  Just need some opinions about this...

I'm guessing that it's the original, so 19 years old (2001).  It seems fine until it gets up over 100 degrees here.  It starts blowing warm air.  Mysteriously, when I turn my manual A/C on in the bedroom, somehow it causes the main A/C to start blowing cool air again.  I know, crazy, huh?  It makes absolutely no sense. 

But then the main one trips the circuit breaker (only when it's blowing cool air).  Yesterday, it tripped it twice--once after about 10 minutes, and then again after about 15 minutes.  That was just yesterday.  it tripped the circuit breaker a few times in the last couple of days.  This all started Monday. Yep, summer is here in Nevada.

My RV guy said that the compressor is wearing out and that's what causes the tripping.  This man appears to be extremely knowledgeable and I don't believe he's just trying to make a buck.  But still, I always like to get a second opinion or many more.  LOL

Since I'm parked and do not travel, I'm thinking about getting an evaporative cooler instead.  My neighbor has one and would set it up for me.  They have one in their house, and it stays nice and cool during the summer.  I'm hooked into his electricity, so it would help them with their bill.  (I'm parked in their yard. They are my friends.)  Of course, it would be much less expensive for me too...

I first thought that maybe my A/C unit just needed some "freon," but the fact that it trips the circuit rules that one out.  Right?  Now I also remember that there was a solar panel on the unit, which my last creepy RV "tech" removed and took with him.  He said it wasn't hooked up, wasn't any good.  How would I know?  I have no idea if that has anything to do with this whole scenario.  He also "serviced" my A/C in February and didn't even have it hooked up correctly.  I had to pay an electrician to connect the loose wire.

Sorry for the long (probably boring) post.  I don't log in very often, but so many have helped me so many times over the years, here I am again.  This is the best site for everything RV, hands down.  8) 8)

 

[Isaac-1]

I am going to say replace it, if you are having to pay labor rates it is not worth fixing otherwise and the "fix" might only last a year or two.

 

[donn]

Evaporative coolers are fine in the desert SW.  Unfornutately everywhere else all you get is a lot more humidity in your RV.  If you wwnt to be cheap go buy one of those split AC units.  Otherwise replace the roof AC units.

 

[StarDancer]

Yep, that's where I am, Nevada.  I'm not traveling.  My RV is parked, has been since 2012.  I don't know what you mean by a "split" AC unit.

Thanks. 

 

[Gary RV_Wizard]

I doubt if an evaporative cooler will be adequate for an RV, which is poorly insulated to begin with.  And somehow the evaporator needs to get connected to the interior of the RV, requiring some non-trivial mods, I would think.

A newer a/c unit  would be more efficient and use less power, but I'm a bit skeptical about the problem. My guess is that the a/c is freezing up when overloaded on a 100+ day, so running the second a/c helps cool & dry the interior enough so the primary can function again. A newer one might help with that too, though.
A "split system" has the compressor outside and a heat exchanger inside, similar to a residential a/c.  A "mini-split" system is very effective and the components aren't hugely expensive, but installation labor could be a killer.

 

[StarDancer]

I am going to say replace it, if you are having to pay labor rates it is not worth fixing otherwise and the "fix" might only last a year or two.

 

I'll be paying the guy for the installation.  I only asked if it was possible that freon just needed to be added.  Because when it blows warm air, maybe that's what gets the unit so hot and then trips the breaker.  I'd have to pay for that too, the freon to be added.  Either way, I'm paying. 

 

[ChasA]

How about a portable unit to supplement the rv ac?
https://www.homedepot.com/b/Heating-Venting-Cooling-Air-Conditioners-Portable-Air-Conditioners/N-5yc1vZc4m4

 

[Gary RV_Wizard]

RV roof a/c's can't just have freon added - they have no inlet to do that, making it a significant mod just to add the filler port.  Besides, you said it works up to around 100 and it works when you run the other a/c.  If that's the case, it's "freon" is just fine.

What about previous years - did it do the job at 100+?

 

[donn]

Yep, that's where I am, Nevada.  I'm not traveling.  My RV is parked, has been since 2012.  I don't know what you mean by a "split" AC unit.

Thanks.

Look at lowes, home depot or do a simple google search for split AC.  Basically the whole unit sits outside is plugged into 120VAC and through a small hole in the wall or through an open window the air is pumped inside. Their pretty cheap, reliable, quiet and efficient.

 

[Lou Schneider]

I'm in southern Nevada.  Several of my neighbors have evaporative coolers and they're happy with them.  They work well in dry air, not so well when the occasional monsoon humidity and thunderstorms roll in.  The key is they're one pass devices - instead of recirculating inside air they draw in fresh air from outside the RV.  You need to open a window at the other end of the RV to let air out so more cooled air can replace it.  If you don't allow airflow through the RV all that will happen is the swamp cooler will make the inside very muggy.

This makes them largely incompatible with an existing air conditioner - you run one or the other, not both at the same time or you'll just dump cooler air out the open window.

As far as installing one on an RV, it works best for a stationary installation.  You build a platform outside the RV to support the evaporative cooler and figure out a way to get it's outlet into the RV.  Usually this means removing a window and building a panel around the inside part of the swamp cooler to block off the rest of the window opening.

 

[TonyL]

If your unit is anything like ours, the two separate AC units share a common supply duct to the vehicle. With only one unit running, at high ambient temperatures it becomes undersized. The return air, which is used to boil the liquid refrigerant back into superheated vapor  so the compressor can raise it back into high pressure high temperature vapor, is so hot, it will not cool the compressor. Therefore, the compressor windings get hot, discharge pressure rises and it trips the breaker. Running the second unit reduces the load, so the compressor runs nearer to normal.
If the system had a leak, it would not take long for the entire charge to be lost, then the unit would not work at all. Ensure the outdoor coil is clean, and reduce the compressor discharge pressure by running a stream of cold water over the front of the coil to see if performance improves.

 

[Ex-Calif]

The solar panel is a red herring - nothing to do with this.

It is possible that an old unit will have the compressor wear out so your tech could be right. I would probably no opt for an evaporative cooler.  I've used them in the past in California but as others have noted they can add humidity to the interior - probably not an issue where you are.

We bought a portable A/C unit for our boat to use when we were docked up.  You can get an 8,000 btu unit for mid-$250 that advertises it can do 250 Sq feet.  They do take up a little floor space and the smallish vent pipe need to be routed outside through a window.

Final solution of course is to replace the roof top one.

 

[StarDancer]

Yeah, it's easy to say, "just get a new unit."  Trying to economize here. 

Here's another thought.  I'm one to investigate and research before I go the way ONE person told me to go. (RV tech)

I've been reading about capacitors and, apparently, when they start going bad, the same kind of "symptoms" appear that I'm experiencing.  RV units have two:  The "motor run" for the blower (fan), and the "motor start" for the compressor.  My friend suggested this because his friend's A/C wasn't coming on, bla bla bla, and they just replaced the capacitors.  From what I've read online: "The capacitor is a small part inside your cooling system that helps regulate the electrical flow. A capacitor that is not working properly will blow fuses left right and center."  And when it blows warm, it's because of the motor start capacitor is going bad (compressor).  Which is exactly what is happening!

Also, I have a regular home thermostat installed (Honeywell).  This is the third one I've had, same one was here when I bought the RV (2011).  But it's only one-speed.  And I hear my A/C unit "reve up," so to speak.  I'm purchasing a Dometic plain old analog with two speeds.  The new unit I would be buying is three-speed...

BTW, I called the RV tech and told him about the capacitor "theory"...and he was indignant, told me he's been doing this for a long time, he knows what he's doing, etc.  These RV techs piss me off, with their big egos.  Don't question him, how dare me!  He never looked at my unit, just climbed on the roof to tell me what BTU it was by looking at it.  ??  I wish I could fix every damn thing in this RV.  I paid him $80 for that. 

 

[StarDancer]

RV roof a/c's can't just have freon added - they have no inlet to do that, making it a significant mod just to add the filler port.  Besides, you said it works up to around 100 and it works when you run the other a/c.  If that's the case, it's "freon" is just fine.

What about previous years - did it do the job at 100+?

Previous years, A-OK!  No problems.  Been in current location since 2012.  Hot, desert.

 

[Arch Hoagland]

You need to know exactly what your voltage is coming into your RV.

If it is low...under 105 volts for example, your air conditioner will draw MORE current and kick your circuit breaker off.

You say you are connected to your neighbors power. It's important you keep an eye on your power.

I use one of these inside my RV plugged into a wall outlet

https://www.amazon.com/Eversame-80-300V-Voltmeter-Measuring-Household/dp/B015H0A3FO/ref=sr_1_6?dchild=1&keywords=ac+power+meter+plug+in&qid=1591329454&sr=8-6 

When it says 105 volts or less I immediately turn off my air conditioners. 

 

[Isaac-1]

The symptoms you describe don't really shout capacitor to me, though I guess it is possible, and is certainly straight forward enough to try.  You will likely need to get someone to go up on the roof, pull the cover off the air conditioner and get the specs off the capacitors, then order a pair of new ones that match the ratings for the old ones, and install them.  Removing and installing the capacitors is straight forward, they are probably held in place with a clip or clamp, and each have a couple of wires connected with push on connectors at the top, call it a 5 minute job to change out once the cover is off the air conditioner.  If ordering online form Amazon, etc, the capacitors should be $25 or so if you buy generic branded capacitors.

 

[Ex-Calif]

I totally understand you don't want to get ripped off and that "techs" often go to the easiest solution which is change parts.

I reread your post about how the front A/C starts getting cold again when you turn on the back one. I am with the others that it is probably not a capacitor.  A capacitor is fundamentally a "surge" device. When the A/C starts or the compressor cycles the capacitor stores "some" energy to help the surge. If the unit didn't start or blew a fuse every cycle I would be looking at a capacitor. If the unit is running and the compressor has cycled the capacitors have nothing to do with whether it blows cold air.

Before I started spending money on labor I would buy 2 vent thermometers. The AC guys have accurate ones but you can find cheap ones online or at an autoparts store. They basically clip onto the face vents (in a car) and read the temp coming out of the vents. Put one on the front unit and rerun it as you describe.  Then do your trick to turn the back one on and measure the temps on both under all conditions.

You may be perceiving the front is getting colder but it may be the back is just helping out over all - temperatures at the vents will tell us something. I am worried you're going to go down the $$ labor and $$ parts and eventually end up at the same place with a $$$$ replacement unit.

If the unit runs and cycles and does not blow fuses then it is working.  There are a couple of other things that can go wrong - refrigerant leaked out or fluid expansion valve is blocked/dirty or (if it has one) the high pressure fluid filter is clogged. I have done auto A/C work and the theory is exactly the same - what I don't know about window type/split type is whether they are serviceable as far as fluids/expansion valves and filters. It the unit has servicing taps then 5 minites with an A/C servicing manifold will tell the tech exactly what's going on.

I am 100% with you.  Before I spent a ton of money on a new one I would tear it up and try to fix it. Unfortunately (for you) I can do all my own work and you have to spend labor hours on someone who may or may not know what they are doing.

(ETA - The question about the shore power is not a bad question. I am curious what kind of circuit you are on.  The idea of low voltage makes some sense but low voltage would indicate that there is a high draw into your grid or a low voltage coming from the circuit in the house you are tapped into. The fact you can start a second unit and everything gets cold again indicates there is sufficient power into your unit. If we knew what the circuit size/quality was we could eliminate that as a cause. Do any of the supply cords get warm/hot? Are you blowing any house fuses?)

 

[StarDancer]

It is my neighbor who says it's the capacitor.  The unit works great until it starts pushing 100 degrees.  It works just fine, went all night.  However, the circuit just now tripped, and it's not even noon...99 degrees.

He is the person who would be installing the motor start capacitor (compressor).  Quite frustrated right now just trying to locate the correct capacitors for my RV using the model and serial numbers.  Asking him to check the unit for spec numbers, well, is like pulling teeth.  He's busy with his business and whatever else he does.  ;D ;D

Just about ready to say, "screw it" and order the freakin' new unit, over $800.  I'm also going to order a Dometic thermostat.  I'm wasting too much damn time with this.    I'll instead focus on increasing my income since I do write books, and that's what I should be spending time on!

I took my dogs to the groomer yesterday and didn't have the second unit on.  It was 103 degrees inside my RV when I got back.  Of course, the circuit had tripped.  It took a while to get that temperature lowered.  My poor dogs were noticeably uncomfortable and I was too.  I quit!

Thank you for your input!

 

[StarDancer]

If your unit is anything like ours, the two separate AC units share a common supply duct to the vehicle. With only one unit running, at high ambient temperatures it becomes undersized. The return air, which is used to boil the liquid refrigerant back into superheated vapor  so the compressor can raise it back into high pressure high temperature vapor, is so hot, it will not cool the compressor. Therefore, the compressor windings get hot, discharge pressure rises and it trips the breaker. Running the second unit reduces the load, so the compressor runs nearer to normal.
If the system had a leak, it would not take long for the entire charge to be lost, then the unit would not work at all. Ensure the outdoor coil is clean, and reduce the compressor discharge pressure by running a stream of cold water over the front of the coil to see if performance improves.

Nope.  The second unit has no ducting...  It's like a window a/c unit only on the ceiling.  LOL

 

[sadixon49]

I would make sure that the cooling coils are clean. What you describe is a classic sign of high head pressures, and that is usually caused by dirty evap coils. So open up the top covers and hose it out. If this has already been done, or you KNOW the coils are clean, then I suspect that your RV tech is correct. Yes, you may get it going with a capacitor, which will have some cost to install, but a 19 year old Rv AC unit which has been road hard and put up wet, has very little life left in it. Living in the desert is a hard life for an AC unit. Other peoples suggestion to check incoming power is a good one, but all that being checked out, I would be inclined to replace it.