Advice ? My Air conditioner stopped midday during camping...

[highender]

hello all:

I have a 2009 WInnebago Navion on Sprinter chasis.

This past July 4th weekend, it was hot when we went camping...and after the hookups were in place . We left AC on during midday while we were out. It was hot in SHasta area. During midday the AC stopped. No fuses were tripped. At afternoon or evening the AC works fine, as well as mornings.

Does this Coleman type AC unit reset when it is overworked ? DOes it need a rest period ? Is this normal ? Was unit shutting itself off to protect from overuse ?


(I recall one of the sprinter trucks I used to drive, when deliverying during hot days, would stop cold AC , and I had to turn it off , for about 5 min, and after that, the sprinter AC would work fine again.
Does it need time for refridgerant to cycle back ? So I am wondering if the same could be going on for the House AC unit for the winnnebago )

[Wyatt]

Is there a way to follow a post like this without typing “following”, or doing what I just did?

[backtrack15]

Thread tools > subscribe to thread

This happened to us as well after 10 hours of continuous use. It was not due to ice on the coil. Seemed to work again later. I am subscribed as well.

[imnprsd]

* To follow a thread without posting a comment, first you need to log-on, and then you just click on the Thread Tools tab above.

OP: Was it over 100F?

I don't know your particular AC, but when an AC has a hard time starting in 100F+ heat, the reason could be the PTC-R "motor starter." Why?

ACs use a "Hard Start Kit" that includes a Start Capacitor and a PTC-R. The PTC-R is a bi-metal semiconductor switch that is supposed to open milliseconds after the AC starts... and it remains open so the start capacitor is no longer "active" in the circuit. I.e., the PTCR creates an "open" the circuit.

The problem is that the PTCR can be affected by outside high heat. And YES, it is COMMON to wait up to 10 minutes before you can restart your AC, so the PTCR can cool down.

TIP: In high heat, lower your thermostat so the AC never cycle on-off-on. This way your AC is never needing to re-start; and re-starting the AC is harder on the system vs. the fist start.

the PTCR "motor starter" does not fail that often, but the outside casing can melt if your shore power or generator is not putting out 110+Vac or more. And they are hard to find for sale... except of you buy one on Amazon made for a refrigerator and then you wire in the device.

ALL ACs NEED SERVICE

You need to do a visual inspection and if you find an AC start or run capacitor out of spec, or a PTCR that is not measuring 20-ohm to 25-ohm range, then you just need to replace these parts.

The truth is: ALL AC's need maintenance and you would be wise to do it every 3-5 years or ASAP if you spot a symptom like described above or any other symptom. Including your AC not working as efficient as you remember.

HARD START ALTERNATIVES IF YOUR AC WILL NOT START IN 100F+ WEATHER

* IF you AC did not come with a hard start kit, you can add one.

* You can replace your OEM Hard Start Kit with a Supco SPP4E, which does does not use a PTCR to switch-out the start capacitor after the AC starts.

* The more popular Supco Hard Start Kit is a SPP6, but I think you may find the capacitor value is too high for a good working AC system; and I would only try this if your AC compressor is showing signs of wear; and none of the other recommendations above work.

SOME SMALL GENERATORS HAVE TROUBLE STARTING AN AC DUE TO HIGH "INRUSH" CURRENT

* When your AC starts it pulls 4-6x the amount of current is takes to keep it running for split seconds during the start-up phase. That means your 10A AC will take 40-55A of "inrush" current; and if your generator can't handle this current demand your circuit breaker may trip or your AC will not start at all... or it will struggle to start and it won't be long (1-2-3 years ???) that your compressor burns-out.

* So you can play around with different Hard Start Kits or you can pay $300+ for a Soft Start device... and this little jewel is what most small generator owners do.

==> So if your AC works find on shore power, but flakes out on generator power, you may want to go this route.

[highender]

Thanks ... that was quite complete.


NOw mine was on shore power, not generator.... But like you said... maybe the AC was restarting and stopping, so it took a toll and had to reset and cool down ?


About how much does the hard start kit costs ?

Or can I still go on with what I have now... since now it works fine. ( though I have no idea if and when we go on long trip ....

Maybe alternative is to turn off AC when ever we can ?

[imnprsd]

It's always a good idea to know how much voltage you are getting BEFORE you turn on your AC. Why? As your AC voltage drops your AC current (amps) increases. And it high heat your AC rotary compressor will work harder and draw more amps as well, albeit fractional.

"They" say to never plug into an AC source less than 108V or more than 132V (=/- 10% from 120V), but I will not plug in when less than 110V, and instead I will run my generator or move to another RV site or park.

Your AC is already putting your "load system" in the upper 90% of you RV service limit; and all RVs are build this way.

Further, when you draw amps from "inductive load" motors, like your ACs, your ATS relays can only handle so much current... for so long.

In this case your AC was running for a long time... near peak amps... and your "Thermal" circuit breakers popped when the heat in the wires got too hot, like they are supposed to.

And then the OP said his AC ran normal after the OTA cooled down and/or the "load system" cooled down.

The more important metric is to monitor the temperature of the cold air coming out of the vents. And what you want to see is -20F or more compared to the inside temperature.

===

In this case, it sounds like the OP's AC run and start capacitors should be with-in spec if your AC starts normal and runs normal, but if you should ever experience these symptoms again (as previously mentioned) then you really should check your AC components even if your AC is running and you think it's working properly. But if the cooling is less than -20F then you absolutely need to do an AC inspection and tune-up if necessary.

PS You can use a $10 digital meat thermometer to check the temperature coming out of your air vents; and I keep a volt meter plugged into a wall socket so I can give it a glance every now and then.

NOTE: If you have any problems with your AC you would do well by getting it checked out immediately, unless your problem occurred like this OP described and you CB popped after running the AC for a long period of time.

In fact, the bigger problem here is if there is any damage to your ATS relays which these days are made out of Contactor-Relays instead of the old style, heavy duty 8-pin relays.

So under high heat conditions and you pop a circuit breaker, you need to put both that appliance circuit on watch; and you need to put your ATS on watch. ...Which my work fine for years to come, so try not to forget about this incident.

Same goes for your engine anytime you get a "check engine" light flash and go off. I.e., you need to write down when, where, how, mileage, and any symptoms you experienced, because these may be relevant down the road.

As for HSK costs: $40 for both the capacitor and motor starter, but before you buy one you need to measure what you have and verify the capacitance values. For example, the Dometic HSK below has too small of a capacitor for my basement AC, but it maybe the right part for your rooftop AC... but we both use the same Motor Starter (PTCR). Note: You can also by separate capacitors for less than $20 and you can re-use your Motor Starter if the PTCR measures 20-25 ohms at rest and "continuity" is good. ...And PTCRs normally do not fail unless your voltage source is less than 110V, because then the PTCR can get so hot it can melt the plastic case it comes in.

So for $20 - $100 you can fully tune-up your AC with a multimeter that can read capacitance.

[09 harley]

Two choices. The ac usage was heavy during the hot day and with all the ac’s running the voltage went down and your ac shut off because of this.
The ac was not cooling itself properly and it shut itself off for safety reasons.
There are modifications you can make to the outer ac housing to improve airflow by over 200%. Not hard to do. Let me know if you’re interested.

[Morich]

A couple details before jumping to the idea that the RV has a failure.
One is to ask if you were there to verify the AC quit but the power coming to the RV was still good?
In areas where heat is not so common, it is true that things get overloaded in the campground or whole area and there are things that trip or get overloaded and shut down. So knowing if it was ONLY the AC which quit or the larger picture having problems can be a clue. No need to try to fix the RV if it was the whole campground out!
We are reaching a crisis point on keeping power flowing in many places. Interested in getting a wide view of what might happen?

This is an article about an MIT study done in the '70's:\
https://www.dailymail.co.uk/sciencet...y-reveals.html

Not that it will change the campground power situation today but I've been to Lake Powel to see what's going on there!

[Wyatt]

Originally Posted by 09 harley

Two choices. The ac usage was heavy during the hot day and with all the ac’s running the voltage went down and your ac shut off because of this.
The ac was not cooling itself properly and it shut itself off for safety reasons.
There are modifications you can make to the outer ac housing to improve airflow by over 200%. Not hard to do. Let me know if you’re interested.

Who wouldn’t be interested?

[Lowdie24]

09 Harley,

I too would like to hear how to increase air flow by 200%.
Please enlighten us.

[R2D2]

Originally Posted by Lowdie24

09 Harley,

I too would like to hear how to increase air flow by 200%.
Please enlighten us.

Me 3.

[Podivin]

Originally Posted by R2D2

Me 3.

As would I.
I'd also be interested to learn how you measured the air flow to know that it's double what it was before. Or would that be three times what it was. Hmm... so if air flow as improved 50% that would mean that it's moving all the air it was before plus 50% So a 100% improvement would be double, a 200% improvement would be triple. That's enough air moving to mess up my hair!

[09 harley]

Originally Posted by Lowdie24

09 Harley,

I too would like to hear how to increase air flow by 200%.
Please enlighten us.

Not sure where I read about this suggestion but it works as reported. I’ve made this change with several of my friends and we have all been more than pleased.
Air flow is key to any cooling process. The change made helps increase the airflow of the AC exhaust. The air is drawn in and usually exhausted out the back. I have an anemometer and the increase in airflow is over 200 % as stated in the article I read. This enables the unit to run for shorter times and also to maintain efficiency as the temperature rises. I can be in 100 + temps and no problems maintaining the temp I want.
The change involves taking off the AC cover. On my Coleman Mach unit I have exhausts on the back and both rear sides. These openings have vertical bars that are U shaped. The air flows over the U’s on the intake side pretty well. The problem is that the exhaust strikes the open part of the U. This causes severe turbulence and really impedes airflow. To test this yourself put your mouth close to the U’s and blow. Most of the air will come back and hit you in the face. Now you understand why this tip helps. Cut out the vertical bars and use screen door metal screening to replace them. I used the aluminum tape used for your heating vents at home. Cut the screen oversize and use the tape to hold it in place. I’ve had this in place for 3-4 years. It won’t let go. That’s it. Put the cover back on.
This is similar the keeping your AC unit at home clean. You wash your coils every year or at least you should to maintain the efficiency.
A side benefit is that my AC is quieter because all the turbulence is gone.
Let me know if you have questions.
My changes to my fridge have enabled me to get down to my set temperature in a couple of hours and I can put ice cream in the freezer and it stays rock hard. Runs less and temperature doesn’t affect it ability to cool. I have helped others make the same changes. My daughter has a fridge with both the intake and exhaust on the side. Those are notoriously inefficient. Works great now. Also with the internal fan controlled by the control the ice formation is completely eliminated. Great modification.
Airflow is very important.

[crah]

Originally Posted by 09 harley

Not sure where I read about this suggestion but it works as reported. I’ve made this change with several of my friends and we have all been more than pleased.
Air flow is key to any cooling process. The change made helps increase the airflow of the AC exhaust. The air is drawn in and usually exhausted out the back. I have an anemometer and the increase in airflow is over 200 % as stated in the article I read. This enables the unit to run for shorter times and also to maintain efficiency as the temperature rises. I can be in 100 + temps and no problems maintaining the temp I want.
The change involves taking off the AC cover. On my Coleman Mach unit I have exhausts on the back and both rear sides. These openings have vertical bars that are U shaped. The air flows over the U’s on the intake side pretty well. The problem is that the exhaust strikes the open part of the U. This causes severe turbulence and really impedes airflow. To test this yourself put your mouth close to the U’s and blow. Most of the air will come back and hit you in the face. Now you understand why this tip helps. Cut out the vertical bars and use screen door metal screening to replace them. I used the aluminum tape used for your heating vents at home. Cut the screen oversize and use the tape to hold it in place. I’ve had this in place for 3-4 years. It won’t let go. That’s it. Put the cover back on.
This is similar the keeping your AC unit at home clean. You wash your coils every year or at least you should to maintain the efficiency.
A side benefit is that my AC is quieter because all the turbulence is gone.
Let me know if you have questions.
My changes to my fridge have enabled me to get down to my set temperature in a couple of hours and I can put ice cream in the freezer and it stays rock hard. Runs less and temperature doesn’t affect it ability to cool. I have helped others make the same changes. My daughter has a fridge with both the intake and exhaust on the side. Those are notoriously inefficient. Works great now. Also with the internal fan controlled by the control the ice formation is completely eliminated. Great modification.
Airflow is very important.

What RV/Coleman model do you have? On my 2020 View, they switched to the Coleman mach 10. The condenser fan is mounted on the inside back but it sucks air into the shroud from the very back and it blows out through the 2 sides of the shroud. Not sure of the u shape bars you are talking about. I'm willing to make any mod necessary that will help any little bit. I'm having a hard time understanding that you can actually keep a coach cold when over 100 degrees. I'd be happy at getting to 76 degrees inside if temps get to 100-110 outside.

[09 harley]

My only suggestion is to remove the shroud and look at it. Not sure if they redesigned the bars or not. If they are U shaped then the mod should help. On my unit my AC cycles on and off in hot temps. I rarely see low triple digits in the Pacific NW.
For the ease and low cost involved this modification is hard to beat.

[backtrack15]

Originally Posted by 09 harley

My only suggestion is to remove the shroud and look at it. Not sure if they redesigned the bars or not. If they are U shaped then the mod should help. On my unit my AC cycles on and off in hot temps. I rarely see low triple digits in the Pacific NW.
For the ease and low cost involved this modification is hard to beat.

I’m curious if you tried using tape to change the bars from U to D and measured the air flow? Regardless, thanks for the interesting tip regarding the U shape.

[Bo Walker]

My front AC stopped working as well. Now I'm trying to find the start capacitor and the run capacitor. I was surprised yesterday that I could not locate replacements from Jhonstone Supply, Grangers, KCW and Camping World in Tallahassee. My guess is that I'll have to order them. My motor home is a 2002, so maybe it's too antique.


I am glad there is a way to get more efficient cooling by altering the AC shroud. I think I'll try cutting the plastic bars away and installing hardware cloth with 1/4 inch squares.

[Fotoguzzi]

Pictures of the u shape things would be more than nice to understand where to cut etc.. pics anyone?

[Jopopsy]

As to the voltage discussion above and increased heat due to low voltage, I always use a autoformer to handle those scenarios.

30 Amp Hughes Autoformer

They have a 50 amp flavor as well.

The unit automatically starts boosting 10% if the voltage drops to 113 or below. It will boost 10% until the voltage gets to 90 volts which is the minimum amount of volts for the unit.

I also plug a Hughes Watchdog EMS into my coach. Pedestal —> Autoformer —> EMS —> Coach. This way the Autoformer has a chance to correct low voltage scenarios, and my EMS will disconnect me if the voltage gets too low even WITH the Autoformer.

[09 harley]

Originally Posted by Bo Walker

My front AC stopped working as well. Now I'm trying to find the start capacitor and the run capacitor. I was surprised yesterday that I could not locate replacements from Jhonstone Supply, Grangers, KCW and Camping World in Tallahassee. My guess is that I'll have to order them. My motor home is a 2002, so maybe it's too antique.


I am glad there is a way to get more efficient cooling by altering the AC shroud. I think I'll try cutting the plastic bars away and installing hardware cloth with 1/4 inch squares.

The larger surface of the 1/4” grid will impede airflow compared to smaller screen door material. I used the black aluminum material and it’s good. I’ll try to find some pictures.