07 Monaco Sig - Communications problem with HVAC Control module.

[grizzly]

My back zone controller a duo therm, all of a sudden it won't turn on Zone 1 It was just working and I turned it off. Came back and turn it on and now it won't even show zone 1 at all. Tried a reset by turning off and holding down the top and bottom button and turning back on but still nothing. Any ideas?

[timaz996]

Pop it off the wall and unplug the "phone cord" and plug it back in a few times. Sometimes they build up oxidation. 

Edited January 1 by timaz996

[grizzly]

Can't get behind it. They left not more than 1/4- 1/2 in of slack wire. Can't even see if it plugs in. Wire in wall won't come out any more. The one zone doesn't even show on the controller now. Only shows 2 of 2 zones when you push zone button. And it was just working!

Edited January 1 by grizzly

[grizzly]

Finally got it off and checked and plugged back in and still doesn't show the 1 zone

[Tom Cherry]

58 minutes ago, grizzly said:

Finally got it off and checked and plugged back in and still doesn't show the 1 zone

Fix is as follows…. ALL THE SIGNALS TO HVAC OR AQUAHOT GO THROUGH THE HVAC DOMETIC CONTROLLER….

Pull off the covers or whatever on each AC. There will be TWO dual inline Phone cable connectors in the Rear and one in the Middle. The rear Dometic HVAC CONTROLLER IS “passing through” the signal, but has lost communication with the thermostat.

There is a poor connection in these connectors.  Use ELECTRONIC cleaner or some rubbing alcohol and a Q-Tip.  Clean the contacts on the male and female ends.  Then plug back in.  Push firmly.  Unplug and reseat.  Then do that a few times….the contacts are the issue in 90% of the “I lost a zone”.  After you do that, you have to do the reset. Thermostat OFF.  Hold top and botton buttons.  Turn switch on. This is like a reboot of a PC, but you have to have a good solid connection.

ODDS ARE, there was a flaky connection and when you turned it off, then it “lost” communication.  Only way to fix.  Clean and burnish the connections and then reset.

Anytime you loss a connection or remove or break a connection….the thermostat has to be reset. BTW, the two wires going up into the control board are NOT polarized.  You can swap the ends….the control modules are bidirectional.

Every once and awhile, there will be an issue in the connection to the Thermostat but usually at the unit. If this doesn’t fix, then swapping the control modules from one that is working to the one that is not….is the troubleshooting.

There have been, literally, a few hundred instances just like yours over the past 14, going on 15 years….the majority were a bad connection.

That’s it….don’t start taking things apart until you do the basics.  I have cleaned mine twice and now carry spare connectors.

[grizzly]

20 hours ago, Tom Cherry said:

Fix is as follows…. ALL THE SIGNALS TO HVAC OR AQUAHOT GO THROUGH THE HVAC DOMETIC CONTROLLER….

Pull off the covers or whatever on each AC. There will be TWO dual inline Phone cable connectors in the Rear and one in the Middle. The rear Dometic HVAC CONTROLLER IS “passing through” the signal, but has lost communication with the thermostat.

There is a poor connection in these connectors.  Use ELECTRONIC cleaner or some rubbing alcohol and a Q-Tip.  Clean the contacts on the male and female ends.  Then plug back in.  Push firmly.  Unplug and reseat.  Then do that a few times….the contacts are the issue in 90% of the “I lost a zone”.  After you do that, you have to do the reset. Thermostat OFF.  Hold top and botton buttons.  Turn switch on. This is like a reboot of a PC, but you have to have a good solid connection.

ODDS ARE, there was a flaky connection and when you turned it off, then it “lost” communication.  Only way to fix.  Clean and burnish the connections and then reset.

Anytime you loss a connection or remove or break a connection….the thermostat has to be reset. BTW, the two wires going up into the control board are NOT polarized.  You can swap the ends….the control modules are bidirectional.

Every once and awhile, there will be an issue in the connection to the Thermostat but usually at the unit. If this doesn’t fix, then swapping the control modules from one that is working to the one that is not….is the troubleshooting.

There have been, literally, a few hundred instances just like yours over the past 14, going on 15 years….the majority were a bad connection.

That’s it….don’t start taking things apart until you do the basics.  I have cleaned mine twice and now carry spare connectors.

Thank you. Will do once it quits rain ing and will let you know what happens

[Tom Cherry]

2 hours ago, grizzly said:

Thank you. Will do once it quits rain ing and will let you know what happens

The covers that I meant were whatever covers the air filters on each individual unit, not the “ROOFTOP” covers.  Sorry for not being clear and misleading you.  The communication cables are accessible from the inside and in the plenum.  So, whatever you take off or remove to install or wash the filters, that “cover” needs to come off.. You will find the connections behind the filter, up in the plenum.

[grizzly]

2 hours ago, Tom Cherry said:

The covers that I meant were whatever covers the air filters on each individual unit, not the “ROOFTOP” covers.  Sorry for not being clear and misleading you.  The communication cables are accessible from the inside and in the plenum.  So, whatever you take off or remove to install or wash the filters, that “cover” needs to come off.. You will find the connections behind the filter, up in the plenum.

OK Thanks for clarification. So the covering that is in the ceiling where the washable filter is correct? And I will be able to see those connections from there?

[DBRV.0]

On 1/2/2024 at 4:20 PM, Tom Cherry said:

The covers that I meant were whatever covers the air filters on each individual unit, not the “ROOFTOP” covers.  Sorry for not being clear and misleading you.  The communication cables are accessible from the inside and in the plenum.  So, whatever you take off or remove to install or wash the filters, that “cover” needs to come off.. You will find the connections behind the filter, up in the plenum.

Tom,

To be clear, your instructions are from the inside??  When I bought my used Dynasty with 3 AC units, the units that would fail to run intermittently, so my son and I went up on the roof and did something similar to your description.  Once the corrosion was taken care of (the 4-wire "telephone" data cables) all was good.  I haven't looked inside - are you saying that mine also has interior data cables?  If so, is there something I can read so I understand the logistics to be able to effectively diagnose in times of trouble?  For example, what is the "path" of data?  And why does the first unit have 2 cables and the last unit have 2 cables if they are all daisy chained together?

- Jeff

[Ivan K]

If you need a quick answer since it is getting late, the cables that you see from the top are just short jumpers to a splitter accessible from inside, below the unit. From those splitters the path continues to a thermostat and an other daisy chained unit so you can see both of them on the thermostat screen. 

[Tom Cherry]

1 hour ago, DBRV.0 said:

Tom,

To be clear, your instructions are from the inside??  When I bought my used Dynasty with 3 AC units, the units that would fail to run intermittently, so my son and I went up on the roof and did something similar to your description.  Once the corrosion was taken care of (the 4-wire "telephone" data cables) all was good.  I haven't looked inside - are you saying that mine also has interior data cables?  If so, is there something I can read so I understand the logistics to be able to effectively diagnose in times of trouble?  For example, what is the "path" of data?  And why does the first unit have 2 cables and the last unit have 2 cables if they are all daisy chained together?

- Jeff

Please go back and reread what i have posted….there was another thread that asked for a follow up.. See my last post….sort of a simplified version….

YES…most issues are inside…..and that, I dare say, is 90+%….rarely at the control module.  The 13.5K are supposed to be in the plenum and you don’t go to the roof.

If you had issues “up top”, then they might have reoccurred.  But, I would first clean the ones inside…..remember, you gotta RESET every time you disconnect….pulling the power kills the memory….and only resetting or rebooting will get it going.

Read the example…in your bedroom, the thermostat data cable goes to unit back there….there is another data cable that then runs to the middle.  That is the end of the line….there is nothing going anywhere else…so one end will be dangling   Maybe s connector on it…but you only need an incoming signal and ain’t no other zone, unless you saw a AquaHot (I think you do NOT have the hidden controller).  Up front….thermostat to the front…no connection to any other unit… Monaco MAY have run a cable....who knows…but the front controls only ONE HVAC…  these two systems are NOT connected….via any DATA CABLES….but they do have the 12 VDC power to every rooftop control module….

READ the owners manual for which thermostat controls which unit and where it is located.

Read the following carefully…especially the followup tonight,

 

[grizzly]

On 1/2/2024 at 2:20 PM, Tom Cherry said:

The covers that I meant were whatever covers the air filters on each individual unit, not the “ROOFTOP” covers.  Sorry for not being clear and misleading you.  The communication cables are accessible from the inside and in the plenum.  So, whatever you take off or remove to install or wash the filters, that “cover” needs to come off.. You will find the connections behind the filter, up in the plenum.

 

49 minutes ago, Tom Cherry said:

Please go back and reread what i have posted….there was another thread that asked for a follow up.. See my last post….sort of a simplified version….

YES…most issues are inside…..and that, I dare say, is 90+%….rarely at the control module.  The 13.5K are supposed to be in the plenum and you don’t go to the roof.

If you had issues “up top”, then they might have reoccurred.  But, I would first clean the ones inside…..remember, you gotta RESET every time you disconnect….pulling the power kills the memory….and only resetting or rebooting will get it going.

Read the example…in your bedroom, the thermostat data cable goes to unit back there….there is another data cable that then runs to the middle.  That is the end of the line….there is nothing going anywhere else…so one end will be dangling   Maybe s connector on it…but you only need an incoming signal and ain’t no other zone, unless you saw a AquaHot (I think you do NOT have the hidden controller).  Up front….thermostat to the front…no connection to any other unit… Monaco MAY have run a cable....who knows…but the front controls only ONE HVAC…  these two systems are NOT connected….via any DATA CABLES….but they do have the 12 VDC power to every rooftop control module….

READ the owners manual for which thermostat controls which unit and where it is located.

Read the following carefully…especially the followup tonight,

 

 

On 1/2/2024 at 4:29 PM, grizzly said:

OK Thanks for clarification. So the covering that is in the ceiling where the washable filter is correct? And I will be able to see those connections from there?

Thanks. Did it today and that solved the issue.Just had to reset the thermostat and it worked the way it should. Problem solved Thank you

[DBRV.0]

11 hours ago, Tom Cherry said:

Please go back and reread what i have posted….there was another thread that asked for a follow up.. See my last post….sort of a simplified version….

YES…most issues are inside…..and that, I dare say, is 90+%….rarely at the control module.  The 13.5K are supposed to be in the plenum and you don’t go to the roof.

If you had issues “up top”, then they might have reoccurred.  But, I would first clean the ones inside…..remember, you gotta RESET every time you disconnect….pulling the power kills the memory….and only resetting or rebooting will get it going.

Read the example…in your bedroom, the thermostat data cable goes to unit back there….there is another data cable that then runs to the middle.  That is the end of the line….there is nothing going anywhere else…so one end will be dangling   Maybe s connector on it…but you only need an incoming signal and ain’t no other zone, unless you saw a AquaHot (I think you do NOT have the hidden controller).  Up front….thermostat to the front…no connection to any other unit… Monaco MAY have run a cable....who knows…but the front controls only ONE HVAC…  these two systems are NOT connected….via any DATA CABLES….but they do have the 12 VDC power to every rooftop control module….

READ the owners manual for which thermostat controls which unit and where it is located.

Read the following carefully…especially the followup tonight,

Hey Tom,

I've tried reading your details, but sometimes I can't translate words into an understanding.  I guess I'm more of a visual person.  This is not @grizzly's setup, but is what I understand of mine.  Perhaps you can review and comment?

The attached image is the extent of my understanding of my configuration.  Maybe AC units are reverse numbered, but in tinkering with the topside (roof) telephone data cables, they behaved like there was a communication chain as shown in red.  When cleaning telephone wire contacts, we cut AC power from the unit being worked on.  Then and now, the telephone data cable out of AC3 is disconnected and all seems to work correctly.  It would be nice to know what it does.  We never did a thermostat "reset", but perhaps that happened by default if power was cut to it.

This morning, I accessed AC3 interior and found telephone wires and a connector inside (picture shown).  Don't know where the wires/cables go.  Don't know if they are related to the topside telephone wires.

Also in the schematic, I don't know if the temp sensors are chained, or a home-run wire to the thermostat, so I show no wiring.

You seem to know boatloads about the setup.  Perhaps you can clarify?

Thanks, Jeff.

[Tom Cherry]

6 minutes ago, DBRV.0 said:

Hey Tom,

I've tried reading your details, but sometimes I can't translate words into an understanding.  I guess I'm more of a visual person.  This is not @grizzly's setup, but is what I understand of mine.  Perhaps you can review and comment?

The attached image is the extent of my understanding of my configuration.  Maybe AC units are reverse numbered, but in tinkering with the topside (roof) telephone data cables, they behaved like there was a communication chain as shown in red.  When cleaning telephone wire contacts, we cut AC power from the unit being worked on.  Then and now, the telephone data cable out of AC3 is disconnected and all seems to work correctly.  It would be nice to know what it does.  We never did a thermostat "reset", but perhaps that happened by default if power was cut to it.

This morning, I accessed AC3 interior and found telephone wires and a connector inside (picture shown).  Don't know where the wires/cables go.  Don't know if they are related to the topside telephone wires.

Also in the schematic, I don't know if the temp sensors are chained, or a home-run wire to the thermostat, so I show no wiring.

You seem to know boatloads about the setup.  Perhaps you can clarify?

Thanks, Jeff.

OK...from the TOP.... here is how your MH is wired.  OPEN the print...  close the left tab so you have a bigger view...then use the PLUS key in the lower right and blow it up.

This is the CORRECT layout.  your drawing needs to be revised...

The data cable runs from Zone 1 (front) to Zone 2 (middle) then DOWN in the bowels of your MH...where Monaco HID THE BRAIN.... On the PRINT that is called ZONE 4.  If you trace the Thermostat or the ON/OFF wires to the Aquahot, that is ZONE 2.  You see the HVAC Brain ZONE 4 Thermostat leads go to the Aquahot Zone 2.  Then you trace back the fan leads from Zone 2. That goes to the VANITY and LAV VANITY Heat EXCHANGERS. 

There is ALSO a separate Temp Sensor for this unit....the Temp Sensor (remote Thermistor).  SO, the one in the BATH area is controlling the Zone 4 which is your Aquahot ZONE 2, but is labeled on the Print as Zone 4.  So, you have to go to ZONE 4 on the thermostat to turn it ON and set the temperature. 

NOW....look at the HVAC Zone 2.  Note where the Temp Sensor is located.  THAT controls the ROOF TOP (HP and AC) for Zone 2... 

Same deal for the Rear Bedroom.  It is called or labeled Zone 3 and there is a remote temp for it.

Read the Owner's manual. It goes into GREAT detail and tells you HOW to use and how to control the system.

Monaco added the Zone 4 Brain circa 2007...but the manual was crappy. I KNOW this exists in the 2008 as Frank McElroy's Zone 4 was messed up. He had to tear a[art some cabinetry and then finally found the hidden brain. It is NOT in any of the ROOF TOP UNITS...  It is simply a "Control Module" that is standalone and buried.

You can PM @Frank McElroy if you want the location or the specifics.

NOW, on SOME of the Monaco Drawings, there is a 12 VDC line that runs from the rear distribution panel and there is a fuse.  It runs directly to ALL ZONES....regardless of whether you have ONE or TWO Thermostats.  In Frank's unit and yours, that would be Zone 1, Zone 2 and Zone 3.  Monaco did NOT run the 12 VDC power to the brain. They depended on the Data Cable to power the Zone 4 brain.  DON'T ASK WHY....we do NOT know. Dometic DOES say that you ONLY need 12 VDC power to ONE of the controllers in the system...and that then powers all... The 4 conductor wire has a pair of DC powered (low voltage...maybe 5 VDC). BUT, Monaco wanted redundancy and did power EACH of the zones, but running that power to the Zone 4 controller was, at least in the 2008's, LEFT OUT...but it will work as it gets 5 VDC from all the other Zones.

The OTHER pair of wire in the data cable is a Multiplexed BUSS run....as in it can communicate, just like your Intellitec MPX in either direction and the Thermostat and sensors can work simultaneosly or MULTI-TASK....like a computer.

That's it...

OK...SPECIFICALLY to your questions....  There is NOT a home run on the power or the data cables. The "data cable" run starts at the FRONT thermostat...and it ends in the REAR (Zone 3) Plenum.  There ain't nothing to plug into.  NOW>>so we're ALL on the same page...when you look inside a unit (and don't ask me about the Middle Zone 2 if it is a 13.5K..  BUT, in the 15's...like UP FRONT.  There are TWO cables hanging down from the top. These are SHORT cables that go up into the interior of the roof top (pull the cover). they plug into the CONTROLLER...they are NOT pictured or called out on the print.  The Thermostat line comes in....then it goes to one of the short cables from the top....then the OTHER short (hanging down) cable) is plugged into the data cable going back to Zone 2...same deal...there is a controller back there....  SOME say it is inside...maybe not.  BUT, regardless, the data cable goes INTO the middle Controller...and then OUT and it goes to the BRAIN (buried) and from the Brain, it goes to the Rear (Zone 3).  Zone 3 only has ONE connection....  the OTHER hanging cable just "hangs out".  It has NO ONE to send the signal to.

That's it....hope this is clear...see the print...

There is (ok...on SOME Patriot Thunders....I saw ONE) NO UP FRONT Temp Sensor. The Thermostat is the SENSOR.  The Patriot has a temp sensor up front on the side of a cabinet.    SO, you do NOT have a front Temp Sensor.  NOW...in the Galley, you have a Temp Sensor.  It does DIRECTLY to the Control Module. It is NOT a data cable or MPX affair... Just a 2 wire run in a jacket. It has a SEPARATE and DIFFERENT plug...   

Next up is the BRAIN....  That is why there is TEMP sensor in the hallway...  The Galley temp sensor controls the UP TOP Zone 2 or middle AC/HP.  The middle (hall) sensor controls the BRAIN for Zone 4 Furnace Aquahot...  Finally, in the rear....the Remote is plugged in to the Controller for Zone 3.

End of lesson.  Study your notes.  You will do well on the pop quiz...  

 

AquaHot Schematic - 2009 Dynasty and up...probably 2008 also.pdf

[DBRV.0]

23 hours ago, Tom Cherry said:

OK...from the TOP.... here is how your MH is wired.  OPEN the print... 

The schematic has an amazing amount of detail - shows that it is a complex HVAC system.  I appreciate your mentioning of a hidden piece (brain) to the puzzle.  Certainly gives me a lot of valuable reference material.  Thank you!