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Wet bay heater and fan


Paul Busch
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  • 5 weeks later...

Just had my wet bay heater replaced, tech shorted the two wires to the snap dics (t-stat) , told me is would automatically come on when the dics closed at 40 degrees. It's 32 today and when I activate the heater circuit on the inside control board it does not come on. The switch inside has a light that turns on, next to it is another light that to my understanding is supposed to light up when the heater come on. Idea on getting this to work would be appreciated.

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Put a remote temp sensor in the bay to see what the temp actually is.  With the water tanks there it may be warmer then you think. 

In 2021 I was traveling in some cold weather, I had the system heat on and kept watching for the indicator light.  Finally when the over night temps were in the high teens and I started driving did I see the light come on sporadically. 

I test my wet bay heat before any trips in cold weather by pulling both wires off the snap disc and connecting them together, which fools the system into turning on.  I check to make sure the heater is heating and the indicator light comes on.  I bought some of these and use one to connect the wires together.  https://www.ebay.com/itm/163923371022?hash=item262a98240e:g:oIYAAOSwiv5duK7u&amdata=enc%3AAQAHAAABAOa4dOjSvGGBLqJW48rp2aWKxkXbji2zoGBBl%2FudVNS74vWVLcp4mXrQa4edyGFe9Gw%2FnO5tKvj3pw5xSjWwi4HuBqUn7IzIxSlziS%2BETbs4zOAP2L7Gm6hUc9znKutU3huFLdmDjQ%2ByqC4NqV%2Fah5Kf6%2F7od4Ej59xYcx%2Fj5%2FUkuJqfDeiiAEJRy2ivSnHPuxvvFdOZ7Owwl6viqMqJdxi4W3tJQMx9C4%2BXqcj3LCR%2FSCdvmWZLjp63cqLrwHm6Ly%2BeIl1um2wXiiKI2bvpQuAfqHcsNg6unKevRs8JFWrrOnBzJ0b2vV0%2FNfxdhwMipyMw8%2B8ozM7BuKPSnWC0rTw%3D|tkp%3ABk9SR9qUnpXBYQ

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18 hours ago, Gospel said:

Just had my wet bay heater replaced, tech shorted the two wires to the snap dics (t-stat) , told me is would automatically come on when the dics closed at 40 degrees. It's 32 today and when I activate the heater circuit on the inside control board it does not come on. The switch inside has a light that turns on, next to it is another light that to my understanding is supposed to light up when the heater come on. Idea on getting this to work would be appreciated.

 

Go to this topic.  Your heater (the Cargo Heater) is one of the poorest things that Monaco did.  The original vendor had one of the heaters "almost melt", then the only person, who had been laid off, came back and modified the internal circuitry....as the LAWYERS got involved.  They put in an UNTESTED thermal overload.  This dates back to 2005/6.  Frank McElroy and myself were assigned to see if there was a fix.  YES, get rid of the original thermal overload and put in one that works.  The two page link goes through all that.  

The system works like this.  The thermostat (snap disk, usually hanging from the ceiling) provides 12 VDC to the Triggering or the ON Circuit in the heater.  There are THREE wires.  One is the Triggering or the Thermostat voltage. The other is the HEATER COIL LINE.  It is fused for 20 amps....but it does not draw that much.  The plate data on the heater is overstated.  It actually pulls 14 - 15 amps.  YES....this is a fact as the lady that checked every heater and repairs them,....told me exactly what she did and such.  SO, the heater only puts out 70% of the plate watts.  

SO, the new heaters usually fail within a few cycles....maybe longer.  MEMORY....when the heater thermostat comes on, that also powers the blower.  SO, you can get COLD AIR....but the internal thermal overload blows up....no 15 amp circuit to the heating coil.

YES....this may sound bizarre....but it is the facts.  There were many folks in the 2010 or maybe later years that were using all sort of fuses and such and trying to come up with a fix.  Frank actually set up a laboratory experiment and had a simulated bay and measured the temperatures and then came up with the new thermal overload fuse....and how to install it and what you need.  I did mine and it worked and then I wrote the "White Paper" of the fix that is in the files.

That's it.  Lots of info in the topic that I linked...but back and forth....if you have a NEW heater....it lasted as long as they do.  It is NOT whoever sold you the heater...it is the inherent design.  Folks have swapped out the heaters with other brands.  BUT, the fix is easy...

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I have mine working as it was setup originally however i would like to get to Tom Cherry's "fix", how do it get to it. not current of finding thing on the forum. Step by step would be appreciated.

A link would be nice!

 

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28 minutes ago, Gospel said:

I have mine working as it was setup originally however i would like to get to Tom Cherry's "fix", how do it get to it. not current of finding thing on the forum. Step by step would be appreciated.

A link would be nice!

 

The LINK is already  there.  Click on the LINK to the older post.  It was included so that you can read and learn.  THEN start at the TOP of Page ONE.....  Towards the bottom of that page is the FIX FILE LINK  that is in our files.....it gives the details....then keep reading...may or may not learn things, but it was written for folks that thought the heat were working buy did not understand HOW to test it or the thermostat...

I chose NOT to double post the FIX Link as most folks benefit from reading and researching the previous posts and information.

OK...practice and experimenting makes perfect.

The Search Box in the upper Right corner can be confusing.  You have to do TWO THINGS.  First find a KEY WORD....then use the DROPDOWN to select WHERE to search.  I sometimes just put in a WORD and click on it....on my iPad it is tough.  That will take you to a screen that might say....NOTHING FOUND or use the Advance Search screen.  I have dual monitors on my laptop and use a docking station, so I get a SPLIT image of each....

Therefore the resolution is way too grainy to print as a JPG or PDF and post...  Look at the pictures below.  I used HEATER in the search box.  Then I selected TOPICS.  that will get you ALL the topics or posts with that....that is what got me to the TOPIC that I posted.

NOW....You can use EVERYWHERE...but that really gets you a lot.  Once you click of the SEACH icon on the right....you will get a screen....with all the info.  If you look the second picture.... that is the ADVANCED Search Option.  If you click on it, it will look like the second picture. 

I KNOW (and others also) that we have Wiring Diagrams and all sorts of HOW TO's or writeups in the FILES....so HEATER and then SELECTING FILES (I didn't change it....just snapped a photo) would take you directly to this....or the THIRD picture.

Now you know....it took me a while to figure out and experiment....but I learn slow....

Hope this helps you and others.....

 

 

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  • 2 weeks later...

EDIT…..

There was an Extensive Topic that is still current on how to test and also how to fix this problem.  Rather than have folks repeat past posts, this topic is merged with that topic.   End of EDIT

Good morning Monacoers, I appreciate this forum.  Might anyone know this answer?  I have a 2002 Monaco Diplomat that came with a Cold Weather Pkg.  Therefore I have a ceramic heater in the bay that has a thematically controlled activation if I turn on the switch on the panel.  Problem is that it seems that it is sporadic.  Might one of you know where that thermo switch is located and what does it look like??  Also is there a way of testing it?? 

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Did you look at the wiring coming to the htr itself, mine was mounted on the htr. Not sure of the parameters for testing, it’s a 12v htr however. I opted for a very small cubed sized 120v htr that I will plug into the receptacle for the block htr and turn it on and off from the block htr switch in the cockpit when needed. I know someone that might have the original htr he would sell. 

Edited by tmw188
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My heater is in good condition.  My concern is the thematically controlled switch that controls it.  I don't know what it looks like or how to test it.  Once the temp is in the 20's and it did not turn on the heater its too late.  There must be a way of testing it......I would think.

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It is little silver snap disc with 2 wires going to it. It is about the size of a sewing thimble located somewhere close to the heater, sometimes all the way on top of the holding tanks. It works on a range of about 40-55 degrees. Best way to test it is to turn system heat switch on and spray it with computer keyboard cleaner or electrical contact cleaner to cool it down so it closes the loop.

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As stated: it is a small snap disk. It can be tested with an ohm meter. However mine was doing the same as what you are stating yours is doing. I tested it and it seemed to be ok but since the problem was intermittent, I decided to just replace it anyway. Now the heater works as it should. Mine was located at the back of the wet bay. A little hard to see and get to, above the drain pipes. I attached a picture of the disk. Ordered

directly from the manufacturer.

20221113_113757.thumb.jpg.42a8f25cf747a19e6e00b7eac3fb602a.jpg

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I have the parts pages for a lot of things on my rig, they have the "Monaco PN" and vendor PN.  This is what it looks like

https://revrvparts.com/item-detail?itemId=24127&organizationId=9

So if you go to a shop to have them fix your rig you could pay up to ~$100 for a snap disc.  YIKES>  do some searches and buy one that it comes on at ~35F and off at 55F, probably can by for ~$10

 

 

Edited by jacwjames
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Larry, 

Your topic and issue was merged with a complete topic just a few weeks old.  It has details about how to find and isolate and when it should come on,  FWIW, your ceramic or Cargo Heater is probably and older one and may not have had the Factory “REVISION”.  In other words, it probably works.  There is a fix that works for the newer heaters.  The light that turns on the SYSTEM HEAT is just a light in the switch.  That gives poser to the Thermostat.  When the thermostat closes, it sens a signal to the TRIGGER or ON control circuit in the heater.  It also sends voltage to the IN USE or ON Pilot light next to the switch.

People hav dipped the snap disk in ice water and some actually shorted them.  If you remove the thermostat (cut or unplug), you should be able to put it in a refrigerator or freezer with a couple of alligator clips on the leads going to a VOM.  It should CLOSE and the continuity scale or ohms scale will read a circuit,  it is mechanical and does not have to have voltage to make it work,  it is supposed to come on around 35 degrees and go off around 45.

Read the topic from the start and you will understand and then know how to test and which works best for you.  There is, I think, a link to a new thermostat…

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EDIT…. Gentlemen and other members….please do a little research and use the search box.  This is the second new topic that was merged with a very informative and recent topic that should answer all the questions.  Your help is appreciated…End of Edit

Hi Monacoers, it appears that my snap disk does not work.  I opened up the Monaco Parts List and looked up the Bay Heater.  I found alot of good info and have a couple of  questions, if I may.

After reading the information about the failures rate I began to think I would rather just set it up to go on and off when I hit the power switch on my panel.  I noticed in the information on page 144 about "snap disc" in the last sentence.  It says, "if you install a heater with NO Thermostat or On or Trigger Circuit, you MUST put in a Bosch type relay to provide power to the relay.  The Bosch 87 Relay is doing the switching."

1- Can I remove the snap disk and install the relay and be good to go?

2- If yes where would this relay be installed?

3- Would the system be safe to use? I would assume that it is protected with a fused circuit.  Correct?

Thank you in advance for your time and expertise.

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If you bypass the snap disk, it will always be on won’t it? That runs on your house batteries as well.  Be careful.  
I’m assuming for this scenario you would be using the heater switch to energize the 12VDC coil on the relay and wiring the heater leads across the contacts of said relay?  If that’s the case, then the switch is all that controls the heater.  No temperature regulation.  Correct me if I’m missing something.

Fwiw, I questioned the functionality of mine as well, turns out it just wasn’t cold enough.  Once it gets closer to freezing it turns out it worked just fine.  Never had an issue. 
The light only comes on when it’s heating. 

Edited by BradHend
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49 minutes ago, BradHend said:

If you bypass the snap disk, it will always be on won’t it? That runs on your house batteries as well.  Be careful.  
I’m assuming for this scenario you would be using the heater switch to energize the 12VDC coil on the relay and wiring the heater leads across the contacts of said relay?  If that’s the case, then the switch is all that controls the heater.  No temperature regulation.  Correct me if I’m missing something.

Fwiw, I questioned the functionality of mine as well, turns out it just wasn’t cold enough.  Once it gets closer to freezing it turns out it worked just fine.  Never had an issue. 
The light only comes on when it’s heating. 

I don’t know exactly where the quote and information about using a relay rather than the snap disc came from.  It may be in a previous post….and it got overlooked by us (moderators”.  The way the system works is this.

The System heat light feeds 12 VDC (very low amperage) to the Snap Disc thermostat.  When the switch is closed (ON), and the Snap Disc closes (temperature drop), there is a continuous circuit or signal to one of the three wires in the Cargo Heater pigtail.  As long as that signal is on, then the control board in the heater will energize and the fan will run.  There is an INTERNAL Thermostat that cycles on and off the heating element.  BTW….the heater and its data plate is incorrect.  It is only a 15 amp unit….so the 12 VDC calculates out to 1,800 watts.  This is explained and was verified and is included in the file on how to repair a defective unit.  The final Inspector has an Ammeter and she said when it reads around 14, we know it is good and it will be shipped.  She did not have a technical background so EE 101 Elementary DC Circuits was not brought up.

Back on point,  when the Snap Disc closes, the signal to the heater is also sent back up to the “System ON” pilot light..  if you see it come one and stay on for a while and cycle off for while that is normal,  Delta T or differential on the cheap snap disc is about 10 Degrees….so it comes on at 35 and then stays on, until the snap disc warms up to 45.

Therefore the internal thermostat controls the actual heat output and it does cycle on and off.  Larry, the first poster today, may or MAY NOT have the new and NOT IMPROVED model.  We never could pin down a date when they started using the infamous One Shot Thermal Overload “fuse” that has a failure rate ot near 100%.  It was circa 2005/6….

There was a failure of a unit in the field and the owners of the company, who had cut back and laid off the only person with an electrical background, were concerned and, we presume, an attorney pointed out the liability issues.  The heater “ran away” and “melted down and caught fire” is the gist of what we were told when we called and asked about the system and the repeated failures.  The final inspector was responsible for tearing them down and replacing the Thermal Overload “fuse”.  She said that they maybe had had one failure or a few up to the one that melted and then the electrical guy was hired back to fix the heaters….but he just gave them a part number and told them where and how to install and they never did any testing.

OK…if the snap disc is bypassed, then there will be no “shut off” and regardless of the bay temperature the unit will stay on.  Also, the units were never designed as a continuous use heater….so, who knows….maybe that is what lead to the one that melted and caught fire.

From our Moderator’s responsibility, we always try to review and have accurate information, especially when a fire or threat to human life can be the result.  It is NOT recommended to bypass the Snap Disc.  If a more precise control is needed, then search the topics and you will find information for a very robust capillary tube thermostat that was used in the Dynasty and up for controlling the AquaHot bay heater.  It would be a direct replacement and has two terminals and works just like the Snap Disc….and is actually a industrial controller that is used throughout manufacturing plants for temperature control.  It has a much narrower Delta T, so it will cycle much quicker…but will not run up the entire bay to 45…before it shuts off…

Hope  this clears it up and answers the latest questions.

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3 hours ago, BradHend said:

One of the posts had one that was a 5 star with mega positive reviews from Amazon.  Can’t recall the details, but they are out there.  I think them some Dynasty owners have replaced the expensive White Rogers capillary tube controller for maybe $100….and that is the first class way to go.

https://www.grainger.com/product/DAYTON-Line-Volt-Mechanical-Tstat-6EDY7

BINGO…$75 for the real deal….an industrial capillary tube unit that folks have bought for their Dynasty….

OK….I knew we had plowed this ground recently.  

https://www.monacoers.org/topic/5486-wet-bay-heater-electric-cargo-heater-system-heat-inoprative/page/2/

This was ANOTHER topic or thread that is almost a repeat.  Go about 2/3 down on page 2.  I posted two different snap disks that would work…and way cheap..l

This also fills in a lot of details also….

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8 hours ago, Jdw12345 said:

So does the Dynasty and up use a different thermostat and type?

YYYEEESSS…LOL….way .TOO MUCH INFORMATION.

Dynasty and above have an AquaHot bay heater.  That is controlled by an industrial style thermostat or the Capillary ADJUSTABLE tube style thermostat.  The bulb is placed in a spot and then the heater cycles on and off based on the set point.  The range or control temperature is much smaller so the bay stays nearer to a constant temperature.  The info I posted was from a member’s need to replace his and the original White Rogers unit was not available or discontinued.

MOST Camelots/Scepters and maybe Windsors had an optional AquaHot system.  The prints for these systems were copied from the Dynasty, so the optional bay heater, which was SUPPOSED to be included with the AquaHot upgrade had the improved and higher cost Capillary tube control.

Monaco and the Bean Counters and the Supply Chain and untrained assemblers then played havoc.  In the 2009 Camelots, there was NEVER a Capillary tube controller.  A low cost cheap snap disc was used.  So much for MILTEP,S Theory (Make It Like The Expletive Print, Stupid).  They used a higher ON snap disc so the Standard Cargo or Electric Bay heater never came on.  Thus, my dual system has TWO snap disc thermostats and when you leave the AquaHot on, you will never see the electric heater System Heat light come on.

The Diplomat/Endeavor and on down have the electric (12 VDC) heaters and they use the cheap wide band Snap Disc "thermostat”.  

My point and, as stated in the post I included, was that there are lower cost replacements than the $50 one in the link and they meet or mirror the original Monaco installed snap disk.  HOWEVER if one wanted more precise control in lieu of the stock snap disc ( ON @ say 35 and then run forever and eventually shut off @ 45), then one could spend $75 and have a more reliable and robust control thermostat.  And the upside is that the heater doesn’t have to try to heat a large bay and almost runs constantly as it only has say 1,800 watts.  

SUMMARY….cargo heater system heaters were controlled by cheap snap disc and they ran longer, when needed, as they had to raise the temper maybe 10 degrees.

AquaHot system, in the Dynasty, come with the Capillary tube thermostats that ARE ADJUSTABLE.  They are also more precise, and the temperature will be uniform.

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