Jump to content

Short cycling


Recommended Posts

Along with all the problems I have been having my rear ac is short cycling.  Fan is running all the time but the compressor comes on for about 30 seconds and turns off. When I was troubleshooting my phone wire connections I found this wad of balled up wiring in the ceiling. I think this is for the temperature regulation so I don’t understand why this 15-20 feet of wire is balled up in there. I have a sensor in the bathroom under the cabinet and verified a wire is going to it so I’m not sure what this one is for or where it’s supposed to be. Is this supposed to be there right next to the evaporator? It has a little black sensor on the end of it.

F0BFAC8A-DF0B-475E-AB9B-34215DF4E3D4.jpeg

640089D9-5971-4373-B731-254C82D0F74B.jpeg

Link to comment
Share on other sites

If that ball of wire is your phone cord to the ac I suspect it was cheaper to leave the ball of wire vs the labor to cut it and add a new connector.  I have seen 4" heat ducts in the ceiling 5 ft longer than needed that restricts the air flow. 

  • Like 1
Link to comment
Share on other sites

The dark colored end of the wire looks like the sensor that is behind the little plastic hocky mask in my bedroom.

Like ben said that's where your's should be too.  Can't imagine why they left it unfinished or how you would go about installing it where it should be.   However it being up there in the cold air stream is probably why the compressor is short cycling.   If you can see the other end and can unplug it that'll probably stop the short cycling.  I have been told that if you unplug it there is a sensor inside the wall thermostat that will become active.

Link to comment
Share on other sites

Does the short cycleing happen if you set the temp really low forcing the compressor to run all the time?

Where is your thermostat located.

Mine is in the bedroom and it has the temp sensor in it for the rear AC.  My front AC has a separate sensor mounted in the overhead cabinet right above the passenger seat. 

X2 on unplugging it and see if the thermostat takes over. 

Link to comment
Share on other sites

Yes I have turned the thermostat down and it still only runs for about 30 seconds. I am going over today to work on another problem and plan on running the generator so I will unplug it and see what happens. Since I have the sensor out of there it might work better as well. 

Link to comment
Share on other sites

Posted (edited)
1 hour ago, Georgia Mike said:

Yes I have turned the thermostat down and it still only runs for about 30 seconds. I am going over today to work on another problem and plan on running the generator so I will unplug it and see what happens. Since I have the sensor out of there it might work better as well. 

I think you mentioned that you had a sensor in your bathroom.  In my coach that could be in the toilet room or in a hall way where my shower and 2nd sink is. If that sensor is in a hall that would be a reasonable place for it.   Have you looked to see if there is a sensor actually under the plastic cover?  Is it possible that is where the sensor that is hanging hanging down was menant to be?

Edited by Ray Davis
Link to comment
Share on other sites

I think that I would first isolate whether the cycling is due to loss of power or temperature triggered. If the fan is set at anything but AUTO, does it shut down along with the compressor?  If not, it isn't likely due to EMS or other power source. My rear and front units use internal thermostat sensors,  two different thermostats, the only remote sensor is for the center unit, near the shower. Bedroom cycles faster than front or center but that's because the room is much smaller. Certainly not at 30s intervals. If cold air blows directly on the sensor, there is an issue with its location and the solution is obviously in its relocation. As far as I know, there is no low pressure switch, not in my units, so freon level would not stop the compressor. If there are 3 units on a single thermostat, then the 2 external sensors are needed. Freeze sensor as any sensor could also go bad just as the board, hopefully the solution is simpler than that.

Link to comment
Share on other sites

I went over today and unplugged the long sensor wire that was balled up in there. I fired up the generator and the rear ac ran non stop for about 15 min until I shut it off. I had the thermostat set at 65 so it seems like that sensor being up there was causing the issue. And when I say it ran nonstop I mean the compressor ran nonstop. Thank you all for the responses.

Link to comment
Share on other sites

Posted (edited)

If you leave it unplugged it will use the temperature sensor built into whichever thermostat controls the unit.

Certainly odd that it was left coiled up there, unless a previous owner was doing some modifications to the walls / cabinets.

Edited by 96 EVO
Link to comment
Share on other sites

16 hours ago, Georgia Mike said:

I’m not sure what this one is for or where it’s supposed to be.

Mike,

I am not sure about your coach, but do you have a Magnum AGS.  This could be the thermal sensor for that.

Link to comment
Share on other sites

11 hours ago, Scotty Hutto said:

I recently experienced virtually identical symptoms with the front AC on my Diplomat. Turns out I had a bad relay in the Intellitec EMS. 

When the compressor short cycles, do the lights on your Intellitec EMS cycle like you just powered up the coach?  If so, I’d expect a bad relay. 
 

5F3FBCFB-ABFB-4058-96AA-A2465FD1FD0D.thumb.jpeg.679027c7913f8aa9bdce7d4fb6ab5903.jpeg

95482AEC-0394-4F19-BFD5-8F770C9895F2.thumb.jpeg.0acee35be9a824ace31c7220362062fd.jpeg
 

I temporarily bypassed the relay to get my AC working until I could replace the board. 

He does not have the Intellitec EMS.  His Dynasty can be overloaded….as we discussed in a thread that I combined a week ago.

10 minutes ago, Bill R said:

Mike,

I am not sure about your coach, but do you have a Magnum AGS.  This could be the thermal sensor for that.

Nope…I don’t think so.  Monaco ran the AGS sensor from the AGS to right behind where the Dometic T’Stat is located.  That way, you use the same environment that the main TStat is using.  

Link to comment
Share on other sites

21 minutes ago, Georgia Mike said:

I went over today and unplugged the long sensor wire that was balled up in there. I fired up the generator and the rear ac ran non stop for about 15 min until I shut it off. I had the thermostat set at 65 so it seems like that sensor being up there was causing the issue. And when I say it ran nonstop I mean the compressor ran nonstop. Thank you all for the responses.

 

18 minutes ago, 96 EVO said:

If you leave it unplugged it will use the temperature sensor built into whichever thermostat controls the unit.

Certainly odd that it was left coiled up there, unless a previous owner was doing some modifications to the walls / cabinets.

That's good news, next is to leave it unplugged, set the temp to a realistic setting and see how it functions.

On my bedroom A/C I can't use the numbers showing on my thermostat as the temp that I really want.  As Ivan said the room is small so it wiil shut down too soon leaving me uncomfortable.  I end up going by trial and error.

Link to comment
Share on other sites

1 hour ago, Georgia Mike said:

I went over today and unplugged the long sensor wire that was balled up in there. I fired up the generator and the rear ac ran non stop for about 15 min until I shut it off. I had the thermostat set at 65 so it seems like that sensor being up there was causing the issue. And when I say it ran nonstop I mean the compressor ran nonstop. Thank you all for the responses.

OK…lost my original response.  Go to your manual.  Pages 135 and 136.

Front Thermostat controls Front AC and AH…ONLY.

Rear Thermostat controls Rear AC, Middle AC and the AH in these zones.

You are SUPPOSED to have a REAR REMOTE SENSOR, presumably on the wall.  There is a figure showing the design and that note.

So, DO YOU HAVE A as all 1 1/2 - 2” black/brown small dome with a grill or openings.  Look around.  It should be on the wall on the Wardrobe side…the front one.  
I tried to find a picture….but failed.  

NOTE FOR CLARITY.  The controlling thermostat, when installed or rebooted will determine which AC’s have remotes. Your front one does not have one….so the control defaults to sensor in the wall thermostat…

NOW…back on point…If NOT, Monaco GOOFED.  If you do have the raised dome metal cover, remove it.  Is there a wire or a sensor in it?

Now, the OTHER fallback position is to remove (unplug or maybe unscrew terminals) the remote sensor from the Rear AC. You will have to THEN do the infamous RESET.  Your rear Thermostat will no long “sense” or read the rear AC configuration that has a hard wired sensor attached to the control module.  You can pull the cover off the Front AC and look as the control module (has two phone cables going down.  There will be NO a remote sensor wire or cable. Then look at the REAR one there will be an extra “wire” or a jacketed two conductor cable with wires inside,  That MOST LIKELY goes to the sensor in manual’s picture.  The reset will default to the Thermostat’s temp sensor as you have removed the remote.

it you DO have the remote sensor on the wall and there is one just like you found behind it….then, maybe there are TWO wires going to read AC control module and you need to disconnect one and plug in or attach the other.  

NOW, at least you know, in theory, how it was supposed to be installed….and you should be able to figure it out now.

Let us know….

 

12 minutes ago, trailmug said:

Misplaced (and malfunctioning) frost sensor? I think that's basically the only cycling control these have.

BINGO….I think we have a winner.  The original photograph was not very clear.  If you read my “theory” post, the remote sensor is different….or at least what I could pull out.

https://pantherrvproducts.com/dometic-duo-therm-3312303-005-rv-air-conditioner-thermistor-freeze-control-sensor/
 

Mike should be able to look at either the front or middle unit and see the sensor….or Google it as to where and how it is affixed.  If the rear AC does not have one, then this one needs to be routed topside and installed correctly.

I was having difficulty in believing he did not have the rear sensor…maybe just didn’t comment.  So… now two explanations….

Thanks for this post…. I understand the circuits but have never had to get involved in the top side that much,  learned something…as usual.

5E10B10C-4120-4384-A683-655F663E2932.jpeg

Link to comment
Share on other sites

I have looked all over for a sensor cover like the one under the bathroom cabinet. There is a wire going from the middle unit to the bathroom but it seems the rear bedroom just had the sensor balled up and stuffed up in the return air box. There is only one of those sensor grills and it’s in the bathroom. So since I have disconnected it from the rear ac from what you are saying it will cycle from the thermostat now or do I have to connect this sensor and run it somewhere. I think I could figure out some way of installing it but if I don’t need to that would be great. Here are a couple of pictures of the wiring in the rear ac. I have unplugged the sensor wire.

AAD99763-0551-4140-AC54-6717EBD5FAAA.jpeg

32B3CA2C-1429-4AE7-B973-713EFEA492E4.jpeg

This is the sensor that was stuffed up in there that I took out

0EB91136-6FAC-48F9-A6A5-A0CD2511A666.jpeg

Link to comment
Share on other sites

Is the thermostat that controls this unit in the bedroom as well?

Suppose someone at the plant could have forgot where they were at when they returned from lunch.

Link to comment
Share on other sites

1 hour ago, Georgia Mike said:

I have looked all over for a sensor cover like the one under the bathroom cabinet. There is a wire going from the middle unit to the bathroom but it seems the rear bedroom just had the sensor balled up and stuffed up in the return air box. There is only one of those sensor grills and it’s in the bathroom. So since I have disconnected it from the rear ac from what you are saying it will cycle from the thermostat now or do I have to connect this sensor and run it somewhere. I think I could figure out some way of installing it but if I don’t need to that would be great. Here are a couple of pictures of the wiring in the rear ac. I have unplugged the sensor wire.

AAD99763-0551-4140-AC54-6717EBD5FAAA.jpeg

32B3CA2C-1429-4AE7-B973-713EFEA492E4.jpeg

This is the sensor that was stuffed up in there that I took out

0EB91136-6FAC-48F9-A6A5-A0CD2511A666.jpeg

WHOA....your pictures and the description are confusing me....as well as I am working with another member....so FROM THE BEGINNING...

EDIT>>>>IMPORTANT...  As I said, I have two of these going. I NOW fully understand your post.  FIRST....GOOD JOB.  You have removed the WHITE Plug or the Remote Sensor from where it was plugged in on the board. The first photo in your post showed it running to the ceiling. The second showed the end....THAT is what confused me. I just found an OLD manual for trouble shooting.  The WHITE WIRE or WHITE PLUG is the REMOTE....

You do NOT need to do any MORE rewiring or such. Keep that sensor and store it....for posterity....I never throw mess away.

NOW....you MUST do the SYSTEM RESET...  I'll bet the board looked like the one below....you did great....White is pulled.....read on...

E625BCE8-084F-4F1C-A1EF-AF8F42F8F856.jpeg

The above is what the Control Module or the Board looks like. Notice the three plugs....the Patriotic ones.... the RED, WHITE and BLUE....you should have ALL THREE of these on your MIDDLE AC....I SUSPECT that you have ALL THREE on the REAR AC as well.  That means that BOTH AC's are controlled by a REMOTE sensor. We NOW know that is the WHITE ONE.  SO....do the following....

System Reset or Reboot....like a computer....

Turn OFF the Thermostat.  Hold IN BOTH the ZONE and MODE BUTTONS. TURN ON THE POWER.  FF should appear... When you release the two buttons....it will be good to go and show you the normal display modes and such. You are NOW ready to test. The absence of the REMOTE sensor then allowed the Thermostat to DEFAULT to the internal sensor....which is what you wanted.  If should work fine....and the middle one will still be remote sensor controlled.....

NOW....when you have time....READ the following. I like for folks to UNDERSTAND what they did and how it works.....

I just copied if from another Dynasty 2006 post....as we are doing DUAL AC FIXING TODAY....

NOTE: I am adding the MANUAL for trouble shooting that I just found buried in my vault of files.  It has PICTURES at the end and identifies the THREE wires or sensors.....  

OK....I HOPE that is clear.  You really NEED to understand how this works.  I just posted this on another thread....so it explains....BOTH have a 2006 Dynasty....READ ON...

Front Thermostat ONLY controls the Front AC.  The FURNACE DIP (Fifth from the LEFT) must be ON....NOTHING ELSE

Middle AC (the one I THINK in your picture).  Labeled as ZONE 2 NOTHING ELSE.  NOW a word of Explanation. You have the OLDER AH unit. It does NOT have a fourth zone, like the 08's or maybe the 07's do. SO...the FURNACE SWITCH IS OFF....

Rear AC - Bedroom.  ONLY the FURNACE SWITCH IS ON.  NOTHING ELSE.

Now, for you information and logic. When there is NO ZONE designation, then the Thermostat that "feeds" that loop or end....designates the Unit as ZONE 1.  Thus, no ZONE 1 switch on the DIP. 

Your FRONT AC is controlled ONLY by the Front TSTAT.....

NOW...applying that Logic to the REAR.  The Rear AC only has the FURNACE Switch on. That then designates the Rear AC as ZONE 1.

The MIDDLE, as you know, MUST be selected as ZONE 2.

NOW....to the AquaHot (AH). You only have TWO AH zones. (like mine). There is the REAR Zone.  So the rear AC's control Module has a set of wires going to the AH. When you selected the FURNACE switch, that will allow you to see the FURNACE mode on it....AND it will then control the AH on and off from the setting on Zone 1 or the REAR Bedroom AC.

Zone 2 has NO FURNACE setting because your AH only has TWO PUMPS for interior heat. Thus....leave the Furnace on....

Front....same as the REAR AC. You only have ONE ZONE....and that is what works it....

NOW....for the KILLER....  There are, in reality, TWO separate AC systems.  The phone cables do NOT connect the Thermostats to each other. The Thermostat is the BRAIN...but any time you make a change, you HAVE to reset the thermostat....otherwise, it does NOT know what is downstream

OK....GO GET A CUP OF COFFEE....Seriously I HOPE that explains it. You NEED to check ALL the boards and make sure that ALL the DIP Switches are set correctly.  Seems simple...but Monaco did not do a good job or programming....and in your case, a LOUSY Job of installing as the SENSOR....assuming it is the one...and it DOES look like the Remote Sensor was never installed.  

I have included TWO prints.  The HVAC (38041023) shows what I said in the narrative....and the OTHER is a complete Electronic Copy of your drawings.... Also the Dometic Trouble Shooting manual for the control....

You should be GOOD to go...

2006 Dynasty HVAC Layout 38041203.pdf 2006_Dynasty_Wiring_Diagrams.pdf

ccc5 Trouble Shooting.pdf

Link to comment
Share on other sites

Right!

If that coil of cable has a telephone jack on the other end, it's not for a remote temp sensor.

The plug in end of a remote temp sensor is behind the metal cover. Believe the red plug in Tom's picture.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...