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Houghton Install/Thermostat Dead


klcdenver
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I currently have 2 penguin II A/C Heat Pump units. I am in the process of removing the front unit to install a Houghton. I turned off breaker and disconnected the 2 molex connectors and Dometic 5 Button Thermostat still has power. There are 2 RJ45 plugs going into the penguin control box. When I disconnect 1 RJ45 thermostat still has power. With both RJ45's disconnected the thermostat has no power. Does anyone know what is happening and how to rectify this problem?

Thanks,

Kenneth

402-319-3445

 

I was wrong on the above. When I disconnect the molex that has 12 volts going thru it I get the thermostat back.

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22 minutes ago, klcdenver said:

I currently have 2 penguin II A/C Heat Pump units. I am in the process of removing the front unit to install a Houghton. I turned off breaker and disconnected the 2 molex connectors and Dometic 5 Button Thermostat still has power. There are 2 RJ45 plugs going into the penguin control box. When I disconnect 1 RJ45 thermostat still has power. With both RJ45's disconnected the thermostat has no power. Does anyone know what is happening and how to rectify this problem?

Thanks,

Kenneth

402-319-3445

 

I was wrong on the above. When I disconnect the molex that has 12 volts going thru it I get the thermostat back.

Don’t know your knowledge of the Penguin system….so here goes.  Each HVAC (2 or 3….doesn’t matter) has 12 VDC going to each of the Penguin Control Modules.  When all three are hooked up, and the “furnace” dip set correctly for either the forced air or the AquaHot, there is a multiplexed loop that runs via the phone lines to all units.

The Thermostat has NO DIERCT DC input,  the four lines are broken down (over a phone line or 4 individual strands).  Two of the wires carry the DC to the Thermostat.  The other two is a complex multiplex circuit that controls all the functions.

If you remove a control module or reprogram it, you must reset the system.  That is accomplished by a reboot.  You hold the top and bottom buttons (Mode & Zone? Memory).  The Thermostat must be off.  Then you turn on the Thermostat while holding these down.  Then it will display FF.  That is like disconnecting all the peripherals from a desktop PC and the totally rearranging the USB cords.  The computer will do an automatic “reset” and figure out (Plug snd Play) and identify all the new residents..many are the same….but on different ports.

That is how the Dometic Thermostat works,  it checks out each of the HVAC Control modules and how they are configured.  FWIW  your rear HVAC PROBABLY has a hard wired remote sensor.  When it is connected to the rear HVAC Control Module, that info is put into the Thermostat’s brain,  thus all the zones and modes and options and controls points are known,

NOW what I don’t know is how much you understand the circuitry and the MPX system,  there is a phone line from the thermostat to the front HVAC.  It plugs through a Dual Inline Male to Male phone line,  there are TWO Male phone lines that come from the Control Module in the unit,,,,and the Control Module is located inside the HVAC unit but only accessible from the outside or roof.  The two phone lines are bi-directional.  It matters NOT which one is plugged in to which wire,

So the Multiplex loop comes from the Thermostat…..and goes into the unit (inside under the filter housing)….then that goes up to the Control Module and comes back down.  Then there is a phone line going to the rear (or middle if you had one) unit.  That Phone line must be plugged into one of phone lines coming down from the external Control Module.  Since this is the “end of the line”, the other phone line is not used…but there is a hard wired line to the remote temp sensor on the wall.

This handshake or reboot tells the thermostat how many little boys  and girls and what they like and so forth.  Then the thermostat controls everyone and all is well

You CAN byoass a unit, for example, your new unit up front can be bypasses by plugging the thermostat line into the one going to the rear.  You can program the rear  Control module to be Zone 1….and the internal temp sensor in the thermostat will be bypassed and the remote wall sensor will work.

This is NOT a conventional home system.  It does how have a conventional ON/Off and heating and cooling switches,  all is done electronically.  If your Hiughton unit does not use the same controller as a Dimeric, it will have to have it’s one thermostat and power and such.

YES….this is deep, but one must know this and he advantage and disadvantages of mixing systems,

There MAY Abe some new electronic or Bluetooth thermostats that will work with the existing Penguin and your new unit,  I don’t know about them.

 

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I replaced our two Penguin IIs with Haughton (RecPro) about a year ago. The Penguin II units work in conjunction with a complex central processor for each unit plus remote room thermostats and a central 5 button control panel. The Haughtons are completely independent and stand alone. They each have an internal thermostat with  a monitoring unit attached to the return air side of the condenser coil. The unit is controlled by a touch pad integral with the ceiling unit. In addition there is a remote control that also can control the unit. I discovered that the remotes are not unit exclusive. That is either remote will control either unit so if the setting are from the remotes and you try to set different temps it will cause issues.

Even with the old Penguin controllers left connected and in the plenum, once the Haughton units are connected to the 120vac the 5 button control panel goes dead. I have tried several different rewiring schemes in order to use the wall unit to operate the LP furriness without luck. Although not yet done my workaround is to wire a new thermostat directly to each furriness (we have two).

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7 hours ago, 1nolaguy said:

I replaced our two Penguin IIs with Haughton (RecPro) about a year ago. The Penguin II units work in conjunction with a complex central processor for each unit plus remote room thermostats and a central 5 button control panel. The Haughtons are completely independent and stand alone. They each have an internal thermostat with  a monitoring unit attached to the return air side of the condenser coil. The unit is controlled by a touch pad integral with the ceiling unit. In addition there is a remote control that also can control the unit. I discovered that the remotes are not unit exclusive. That is either remote will control either unit so if the setting are from the remotes and you try to set different temps it will cause issues.

Even with the old Penguin controllers left connected and in the plenum, once the Haughton units are connected to the 120vac the 5 button control panel goes dead. I have tried several different rewiring schemes in order to use the wall unit to operate the LP furriness without luck. Although not yet done my workaround is to wire a new thermostat directly to each furriness (we have two).

Thanks for that summary.  Ken and I spent quite a bit of time on the phone last night.  We discussed how the Control module works and I advised to figure out if the furnaces required 12 VDC or a “power signal” versus a dry contact (thermostat relay) closure.  I hope he will PM you to discuss.

I took him down the path to understand the MPX system and was hopeful that he could use a relay to close the contacts on each heater

It seems that the Control modules has some sort of boot up or diagnostics where the AC has to be connected to work.  Just curious, did you try to do a parallel 120 VAC line to the Dometic Control module.  I cankt find any good explanation of how they work,  All along I had thought that the 12 VDC alone to each was providing control voltage for the board and that, in turn, provided the Thermostat voltage.

From what you posted, if I understand it, it would “SEEM” that the incoming 120 VAC actually powered the control board and there is a step down transformer that provides the Thermostats DC (Lo voltage AC?) power.  
 

Maybe the incoming 12 VDC is for a “shedding funtion”….so if the Intellitec EMS was properly wired….and Monaco NEVER DID….then killing the 12 VDC should shed or cut off the VAC.  Monaco use the EMS AC power relays, .which is a NONO.

 

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20 hours ago, klcdenver said:

I currently have 2 penguin II A/C Heat Pump units. I am in the process of removing the front unit to install a Houghton. I turned off breaker and disconnected the 2 molex connectors and Dometic 5 Button Thermostat still has power. There are 2 RJ45 plugs going into the penguin control box. When I disconnect 1 RJ45 thermostat still has power. With both RJ45's disconnected the thermostat has no power. Does anyone know what is happening and how to rectify this problem?

Thanks,

Kenneth

402-319-3445

 

I was wrong on the above. When I disconnect the molex that has 12 volts going thru it I get the thermostat back.

On my coach, I have 4 zones.  The first 3 zones have the factory AC/HP units and the 4th zone is for the aquahot only.  I just ran a test with the 120 VAC off and I reset the 5 button thermostat by holding the mode+zone buttons while turning on the thermostat.  I got the code FF and I can see all 4 zones.  Now, on mine, each of the 3 AC/HP control boards was only connected to 12 VDC and no 120 VAC.  The 4th zone is not connected to either 12VDC or 120VAC and it does work.  This tells me that if these boards are used to only control heat, at least one of them must be connected to 12VDC.  There is no need to connect to 120VDC.  But after you make all the connections, the thermostat would need to be reset.

Pictures are always worth a thousand words.  These are pictures of my 4th aquahot heat zone only.  The two white wires in the board go to a remote temperature sensor and the top two blue wires go to the aquahot.  The top red 12VDC wire was cut off.  The bottom white, black, and green 120VAC wires are cut off.  The two data cable connections at the bottom go between AC/HP#2 and #3.

Hope this helps. 

IMG_20150420_133450731.jpg

IMG_20150420_133535143.jpg

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I Just finished getting done. I removed the front #1 Penguin 13,500 BTU. On the 13,500 the control box is in the plenum like Frank's picture shows. I removed all the AC wiring from the box. I also removed P3,P4&P5 connections from the box. My front furnace works as it should in furnace mode without adding a new thermostat. My rear unit #2 still works in heat pump, AC and furnace mode as it should.

Note: the newer Penguin's 15,000 BTU has the control panel mounted to the roof under the shroud. It will need a different route to get it to work.

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21 minutes ago, klcdenver said:

I Just finished getting done. I removed the front #1 Penguin 13,500 BTU. On the 13,500 the control box is in the plenum like Frank's picture shows. I removed all the AC wiring from the box. I also removed P3,P4&P5 connections from the box. My front furnace works as it should in furnace mode without adding a new thermostat. My rear unit #2 still works in heat pump, AC and furnace mode as it should.

Note: the newer Penguin's 15,000 BTU has the control panel mounted to the roof under the shroud. It will need a different route to get it to work.

Bingo,

Frank and I have discussed this. What you will be able to do is have split systems.  Don’t run the AC when you are in Furnace mode

Your experiment works

What Frank and I are debating is whether the control sends out 12 VDC to tour furnace or is closing a contact 

Thanks

Loel might be able to reset his system and get it working. 

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22 minutes ago, klcdenver said:

I Just finished getting done. I removed the front #1 Penguin 13,500 BTU. On the 13,500 the control box is in the plenum like Frank's picture shows. I removed all the AC wiring from the box. I also removed P3,P4&P5 connections from the box. My front furnace works as it should in furnace mode without adding a new thermostat. My rear unit #2 still works in heat pump, AC and furnace mode as it should.

Note: the newer Penguin's 15,000 BTU has the control panel mounted to the roof under the shroud. It will need a different route to get it to work.

If you had a remote sensing thermostat connected to P4 and you're not using it on the new unit, you could leave it connected to the old board.  Just be sure to reset the thermostat.  If P4 is empty, the temperature sensor inside the 5 button thermostat will be the default temp sensor for that aquahot zone.

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Thanks. I do not have aqua hot but I should reconnect P4 as it goes to the indoor temp sensor. I am pretty sure it requires a 12 volt thermostat. Take a look at the attached wiring diagrams. Both diagrams show 12 volts to t stat. The plug with thermostat coming of my furnace is square Molex and not long like this diagram but I could not reach it without dissembling a lot of stuff to check voltage on it.

Thanks for the help guys. Oh yea I plugged the Houghton in prior to installing it and it is extremely quieter on the outside than my dometic penguin. In fact the penguin on the roof drowns out the Houghton on the ground standing beside it.

thermostsat.pdf

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I am in a similar ‘boat’ having to replace an a/c but will install a new Penguin.

Dometic advised to install a different control module in the new a/c to ‘dumb it down’ to enable to communicate with the 5 button thermostat. When I replace the other a/c Then I will reinstall the original board and replace the thermostat.

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1 hour ago, Tom Cherry said:

Bingo,

Frank and I have discussed this. What you will be able to do is have split systems.  Don’t run the AC when you are in Furnace mode

Your experiment works

What Frank and I are debating is whether the control sends out 12 VDC to tour furnace or is closing a contact 

Thanks

Loel might be able to reset his system and get it working. 

Tom, the 12 volts signal comes FROM the aquahot control board via Therm-0 and the thermostat board must pass that 12 volts signal BACK to the aquahot control board.

Screenshot_20230223-163724.png

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4 minutes ago, Frank McElroy said:

Tom, the 12 volts signal comes FROM the aquahot control board via Therm-0 and the thermostat board must pass that 12 volts signal BACK to the aquahot control board.

Screenshot_20230223-163724.png

Agreed, per our discussion.  This dates back several months or so when a member kept “blowing up” his control boards.  During the trouble shooting, we asked him to use a VOM and measure the incoming signal, DISCONNECTED, from the AquaHot board.  He set his front and rear thermostats to Furnace.  Both lines measured 12 VDC, but WERE another tested under load.  From our consecrations and texted today, the 12 VDC he read was incorrect from a practical stand point.  All I know iis what he said he read….and both the functional rear and “wondering if I am functional front” looked the same.  He actually reversed the zones and the front unit or registers and pump worked.  This was totally baffling as he would repetitively “blow” the front AquaHot zone section of the main AquaHot control board.  It appears from what the rebuilder told him, the resistor in the Fan control section was toasted.

The rebuilder devised a work around,  they had an isolation relay for the income signal from the front Control board…..and then used another relay to isolate the fan circuit.  I asked for a circuit, but that never was provided.  

The debate or issue was whether the signal from the Dometic was just a “dry contact closure” provided to the AquaHot or s 12 VDC signsl.  That also raised the question of how does a on/off capillary tube thermostat control the bay heater when the drawing shows not DC in the circuit.

From your extensive research and experiments, I agree with you.  There would be no logic for the bay heater to have no voltage and work, unless the AquaHot was providing it and the controller was just a pair of dry contacts.  Your offline comment about the poster maybe not measuring the two leads or misunderstanding something like an MOSFET leakage and being misconstrued as s 12 VDC signal now makes sense.

Bottom line, for what ever reason, his AquaHot rebuilder isolated the two 12 VDC from the original board and whatever “leakage” situation was causing the repetitive board failure now makes sense.

In addition, we now know that the Dometic control board is just “closing” a circuit….and it has 12 VDC on it.  That really clears up the mystique about the infamous “2 blue wires” that are often brought up.

I now have a much better understanding…..and appreciate your doing a deep dive to resolve the mystery….

This will help me and probably others assist folks in the future….

Thanks…

 

1 hour ago, klcdenver said:

Thanks. I do not have aqua hot but I should reconnect P4 as it goes to the indoor temp sensor. I am pretty sure it requires a 12 volt thermostat. Take a look at the attached wiring diagrams. Both diagrams show 12 volts to t stat. The plug with thermostat coming of my furnace is square Molex and not long like this diagram but I could not reach it without dissembling a lot of stuff to check voltage on it.

Thanks for the help guys. Oh yea I plugged the Houghton in prior to installing it and it is extremely quieter on the outside than my dometic penguin. In fact the penguin on the roof drowns out the Houghton on the ground standing beside it.

thermostsat.pdf 1.57 MB · 3 downloads

My gut feel as well as talking about your situation.  Unless you want to get into all the circuit configurations and such…. Leave everything as is in the front Control module.  If I understand correctly, you have pulled the AC power, and unlike Loel, your thermostat is still displaying and you can operate the furnace from the front thermostat and the rear furnace works,  I have a hard time understanding.  Monaco went cheap on the systems….and cheaper as they were used in lower ends.  Don’t take that as a slam.  If you have no “remote” sensor anywhere up front, like you do int the rear bedroom, then the Thermostat, like mine, has the built in thermocouple so it effectively measure or responds like any home system.  The remote sensors were used on higher end models.  I have seen and assisted with a problem in a Patriot,  it was one of the few that I have ever seen with an UP FRONT REMOTE sensor.  Never say NEVER, when it comes to Monaco.  But if you can’t find a remote sensor upfront or never saw it, then the Thermostat is reading the Front Control module as “does NOT have hard wired remote sensor” which translates into “Use the Thermostat internal sensor” for control.

That’s my take…..once you get it going, as discussed, give us a complete field report on how you like it as well as how you rewired or used the existing hardware.

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20 hours ago, Tom Cherry said:

Thanks for that summary.  Ken and I spent quite a bit of time on the phone last night.  We discussed how the Control module works and I advised to figure out if the furnaces required 12 VDC or a “power signal” versus a dry contact (thermostat relay) closure.  I hope he will PM you to discuss.

I took him down the path to understand the MPX system and was hopeful that he could use a relay to close the contacts on each heater

It seems that the Control modules has some sort of boot up or diagnostics where the AC has to be connected to work.  Just curious, did you try to do a parallel 120 VAC line to the Dometic Control module.  I cankt find any good explanation of how they work,  All along I had thought that the 12 VDC alone to each was providing control voltage for the board and that, in turn, provided the Thermostat voltage.

From what you posted, if I understand it, it would “SEEM” that the incoming 120 VAC actually powered the control board and there is a step down transformer that provides the Thermostats DC (Lo voltage AC?) power.  
 

Maybe the incoming 12 VDC is for a “shedding funtion”….so if the Intellitec EMS was properly wired….and Monaco NEVER DID….then killing the 12 VDC should shed or cut off the VAC.  Monaco use the EMS AC power relays, .which is a NONO.

 

The furnace only needs a connection to be made between the Blue wires in order for it to ignite, therefore any thermostat that is powered by a battery and has isolated contacts will work. See the photo below, I added an additional Suburban furnace to my Cedar Creek 5th wheel.

image.jpg

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I am going to summarize what I did to rectify and get things to work on my 2007 Monaco Diplomat 40SKQ. This is not going to apply to models above a Diplomat as best I can tell. The Diplomat does not have aqua heat and some of the fancy things. It only has 2 Penguin II's originally both being 13,500 BTU. If you have upgraded to 15000 BTU your control boards are located inside the unit on the roof. The 13,500 BTU units control boards are located in the plenum between the roof unit and the air diverter box. The communication system to operate the 5 Button Control (standard on Diplomat) for the HVAC system is 12 Volts, AC power has nothing to do with it. Note I can only assure this works with how it is wired thru the front or #1 unit. I removed the front unit (13,500 BTU) to install the Houghton 3800 in it's place. I had to leave the control box in the plenum with only the 12 volt connector hooked to it an P1 &  P2 RJ11 (telephone Jacks). P4 needs to stay which is the temp sensor for the inside for zone 1. I have verified everything worked as before except the Houghton is a stand alone system with it's own remote control. If you want the number 1 furnace to work you will have to select it on the 5 button control board and set your required temperature in Zone 1. The Houghton does not interface with any dometic equipment. I cannot tell you anything about adding a new thermostat or connecting into the 2 blue wires etc... as talked about in other post.  I have my HVAC system working without adding or rewiring anything.

Good luck if you are doing the same thing and feel free to contact me if I can help or assist you. Thanks to Tom for helping me understand some of this better also. I did contact Dometic originally for help and they would not even give me the time of day. The Houghton is much quieter inside and outside. Parts are also available for them where they are not for dometic. Will follow up with decibel readouts when I get everything tidied up.

Kenneth Cox

402-319-3445 or klcdenver@gmail.com

 

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2 hours ago, klcdenver said:

I am going to summarize what I did to rectify and get things to work on my 2007 Monaco Diplomat 40SKQ. This is not going to apply to models above a Diplomat as best I can tell. The Diplomat does not have aqua heat and some of the fancy things. It only has 2 Penguin II's originally both being 13,500 BTU. If you have upgraded to 15000 BTU your control boards are located inside the unit on the roof. The 13,500 BTU units control boards are located in the plenum between the roof unit and the air diverter box. The communication system to operate the 5 Button Control (standard on Diplomat) for the HVAC system is 12 Volts, AC power has nothing to do with it. Note I can only assure this works with how it is wired thru the front or #1 unit. I removed the front unit (13,500 BTU) to install the Houghton 3800 in it's place. I had to leave the control box in the plenum with only the 12 volt connector hooked to it an P1 &  P2 RJ11 (telephone Jacks). P4 needs to stay which is the temp sensor for the inside for zone 1. I have verified everything worked as before except the Houghton is a stand alone system with it's own remote control. If you want the number 1 furnace to work you will have to select it on the 5 button control board and set your required temperature in Zone 1. The Houghton does not interface with any dometic equipment. I cannot tell you anything about adding a new thermostat or connecting into the 2 blue wires etc... as talked about in other post.  I have my HVAC system working without adding or rewiring anything.

Good luck if you are doing the same thing and feel free to contact me if I can help or assist you. Thanks to Tom for helping me understand some of this better also. I did contact Dometic originally for help and they would not even give me the time of day. The Houghton is much quieter inside and outside. Parts are also available for them where they are not for dometic. Will follow up with decibel readouts when I get everything tidied up.

Kenneth Cox

402-319-3445 or klcdenver@gmail.com

 

Ken, you nailed it. I am going to list the experiments and the discoveries your made. Your phone call this morning was great.

No AC to either of the Control Modules.  The thermostat in the front worked for both the front and the rear furnaces….so you don’t need any AC.

Both Modules have incoming 12 VDC from a fuse in the House distribution panel.  With DC still hooked up, the Thermostat will work and control both furnaces.  Unplug the 12 VDC from the rear unit…..both still work.  BUT…PULL the front DC and leave the rear DC hooked  up….Thermostat Is dead.

The “spooky” thing is that the thermostat leads from the Control Module will read 12 VDC when disconnected.  BUT that is a FALSE or Phantom reading,  Your Atwood furnaces, just like the AquaHot control board provides a 12 VDC set of contacts. So, all the Atwood or AH wants is a “dry” set of contacts.  When the Dometic thermostat calls for HEAT, then the two thermostat wires are merely a “closed” switch. These switches are, what I think and learned from Frank McElroy a MOSFET computer integrated circuit component.  In reality is is a miniature electronic relay.  However, if you measure the voltage, one would think that they provide a 12  VDC circuit.  But the current is so low, it probably would not even activate a Bosch relay.  The proper way to test them for “continuity” between the two wires when the thermostat is calling for heat via the thermostat.

Your plan, as I understand it, will be go figure out a way to keep the rear Control module and move it down to the plenum or mount it under the shroud Ike it is on the Dometic…..if you install a Houghton in the bedroom.

All of this was a great education and learning exercise,  Frank and I talked and what you did confirms our understanding as well as provides us with more information to pass on and help others.

Thanks again 

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Ok. It seems like I have a lot of questions but it’s all small things. 
 

I have a dual thermostat that runs 2 ACs. The back AC seems to run just fine with no issues. We have been on a trip since Thursday and Thursday-Friday we had no issues. No issues while technician was working on Rv most of the day Friday. When we packed up to come home we started noticing the front AC was not cooling properly on auto. Would not run or would come on and run for aboit 5 minutes then shut down. It would do this from time to time. 
 

last night and this morning it seemed to do just fine. Compressor would run and it would cycle to keep temp down to where we had it set. I set both AC at the same temperature just to see if they would cycle on and off about the same and they did for the most part 

as the day has gone on and the temperature has risen some. The back ac seems to be fine but the front ac now won’t stay on long enough to cool down to desired temp. I spoke to my normal mobile rv technician who I use for lost everything and he seems to think it’s a control board issue. I cannot get a definitive answer on the web for my exact issue. Most tall about single control issues. 
 

I am assuming if it were a thermostat issue it would be an issue with both ACs. Is my technician on the right track and if not any other thoughts. I have nO diagnostic tools with me and he is scheduled to come see me this week. I am just looking for some info because I trust this group. 
 

thanks

 

Dometic AC 

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I don't know if this means anything in this conversation, but the rear remote thermostat was mentioned. At a ramblin'pushers rally about 15 years ago, the rear remote thermostat  was also mentioned.  In my 05 Ambassador, 5 button control, you can remove the rear, remote thermostat and the 5 button control panel becomes the active rear thermostat.

Gary 05 AMB DST

Edited by Gary 05 AMB DST
better explanation
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9 hours ago, Gary 05 AMB DST said:

I don't know if this means anything in this conversation, but the rear remote thermostat was mentioned. At a ramblin'pushers rally about 15 years ago, the rear remote thermostat  was also mentioned.  In my 05 Ambassador, 5 button control, you can remove the rear, remote thermostat and the 5 button control panel becomes the active rear thermostat.

Gary 05 AMB DST

Yes.  If I understand the terminology…..please look on page  164 of your manual, there is a description and pictures of conventional system used in your Ambassador.  The correct term is remote temperature sensor.  It is NOT a thermostat.  All it does is tell the front Thermostat what the temperature is back there….and then the front Thermostat, which is the BRAIN, allows the remote sensor to activate ON or OFF the rear unit.  To the best of my knowledge, you do NOT have TWO 5 button Thermostats….nor has Monaco ever made a Motor home with TWO five button Thermostat and “interconnected”, using a phone patch line.  The two thermostats would’ve fighting.  When there are two thermostats, typically the front and middle unit work off the front thermostat and the rear works off the rear thermostats.  BUT they are, in reality, two separate and NOT connected systems.

YES…if you “disconnect”, the hard wired remote temperature sensor from the roof control module….one side would be sufficient, then you also have to do a SYSTEM reset.  That reboot (hold in the mode and zone buttons with the lower On/Off switch OFF….then turn on the switch…) then displays  FF.  NOW the Thermostat brain knows there is NO rear remote sensor.  So, the only thing it can do is use ITS upfront temp sensor (see the picture  in the manual) and you have a single temperature control point….but no guarantee of a uniform temperatures. Connect it back up…do a reset.  Bingo, the rear is sends a On or Off signal to the front.

WHEN we see 3 AC systems and a front and rear thermostat, the two systems are totally separate in that there is NO Phone patch cord connecting the two AC systems.  I don’t know how dual thermostats would or would not communicate nor work.  If you have a print, that would be great.  Based on your comment and what is in the manual and what we know from reading the manuals and practical troubleshooting shooting, I can only offer this explanation.

I would also ask you to look at your system and see if you have the “wall mounted” remote sensor.  If you have “two” 5 button thermostats, them Monaco must have been out of remote sensors and you have two, not connecting, systems.

Let us know.  Thanks…

 

 

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Sorry Tom, I had thermostat in my head and never thought about sensor. I have only one thermostat and it is in the bedroom. I also disconnected the front sensor since it was under the TV in the front. I bought a new sensor w/cable and put it near the front A/C. There was a technician at the seminar that gave us that knowledge. Sorry for the misuse of thermostat and 5 button control, I was on a roll!

Gary 05 AMB DST

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3 hours ago, Tom Cherry said:

NOW the Thermostat brain knows there is NO rear remote sensor.  So, the only thing it can do is use ITS upfront temp sensor (see the picture  in the manual) and you have a single temperature control point….but no guarantee of a uniform temperatures.

 

 

When a control board does not have an external temperature sensor connected to it, the internal temperature sensor inside the 5 button thermostat becomes the default temperature sensor for that zone. 

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On 2/24/2023 at 2:43 PM, klcdenver said:

I am going to summarize what I did to rectify and get things to work on my 2007 Monaco Diplomat 40SKQ. This is not going to apply to models above a Diplomat as best I can tell. The Diplomat does not have aqua heat and some of the fancy things. It only has 2 Penguin II's originally both being 13,500 BTU. If you have upgraded to 15000 BTU your control boards are located inside the unit on the roof. The 13,500 BTU units control boards are located in the plenum between the roof unit and the air diverter box. The communication system to operate the 5 Button Control (standard on Diplomat) for the HVAC system is 12 Volts, AC power has nothing to do with it. Note I can only assure this works with how it is wired thru the front or #1 unit. I removed the front unit (13,500 BTU) to install the Houghton 3800 in it's place. I had to leave the control box in the plenum with only the 12 volt connector hooked to it an P1 &  P2 RJ11 (telephone Jacks). P4 needs to stay which is the temp sensor for the inside for zone 1. I have verified everything worked as before except the Houghton is a stand alone system with it's own remote control. If you want the number 1 furnace to work you will have to select it on the 5 button control board and set your required temperature in Zone 1. The Houghton does not interface with any dometic equipment. I cannot tell you anything about adding a new thermostat or connecting into the 2 blue wires etc... as talked about in other post.  I have my HVAC system working without adding or rewiring anything.

Good luck if you are doing the same thing and feel free to contact me if I can help or assist you. Thanks to Tom for helping me understand some of this better also. I did contact Dometic originally for help and they would not even give me the time of day. The Houghton is much quieter inside and outside. Parts are also available for them where they are not for dometic. Will follow up with decibel readouts when I get everything tidied up.

Kenneth Cox

402-319-3445 or klcdenver@gmail.com

 

I have the exact same coach and all of a sudden my front zone 1 ac unit will not run long enough on auto to cool down near the desired temperature. Compressor and fan both come on and then cut off long before reaching desired temp. It seems to actually get to the desired temp at night when it’s cool but no where close during the warm part of the day. The zone 2 ac runs just fine and keeps the temp in the back where it is supposed to. My normal tech is coming out Friday and seems to think it’s a control board issue. Any thoughts. 

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8 hours ago, Gary 05 AMB DST said:

Sorry Tom, I had thermostat in my head and never thought about sensor. I have only one thermostat and it is in the bedroom. I also disconnected the front sensor since it was under the TV in the front. I bought a new sensor w/cable and put it near the front A/C. There was a technician at the seminar that gave us that knowledge. Sorry for the misuse of thermostat and 5 button control, I was on a roll!

Gary 05 AMB DST

There’s nothing to forgive.  It actually allowed a bit of an explanation.  The more that folks understand about the MPX Dometic systems and the revisions that might be necessary if one wants the furnace(s) or AquaHot to work WITHOUT an extensive array of external thermostats, the better and more informed choices folks can make when they upgrade.

Have a free adult beverage and don’t get depressed.  I had to re read and then decide how to answer as I didn’t think you had two 5-button Thermostats….but with Monaco, you never know….

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