Author Topic: OTR Thermostat  (Read 1636 times)

Offline Jcparmley

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OTR Thermostat
« on: April 20, 2018, 09:28:27 PM »
Hello All

I have a MCI 102c3 that I am converting.  I am just starting my conversion.  I removed the stainless registers at the floor.  After removing the registers I started the bus to move it and I noticed the thermostat on the dash read -40.  I think I might have removed the cabin temp sensor.  Can someone advise me as to where this sensor is or how to replace it.  Thanks

Offline sledhead

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Re: OTR Thermostat
« Reply #1 on: April 21, 2018, 04:25:00 AM »
mine was on the driver side at the rear drive tires above the floor near the cold air return vents

dave
dave , karen
1990 mci 102c  6v92 ta ht740  kit,living room slide .... sold
2000 featherlite vogue vantare 550 hp cat
 home base huntsville ontario canada

Offline Jcparmley

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Re: OTR Thermostat
« Reply #2 on: April 21, 2018, 01:37:08 PM »
Do you know what it looked like or do you know where i can get a new sensor?  Thanks

Jared

mine was on the driver side at the rear drive tires above the floor near the cold air return vents

dave

Offline Jcparmley

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Re: OTR Thermostat
« Reply #3 on: April 24, 2018, 03:16:28 PM »
Does anyone know what this sensor is or what it might look like?  I found what I believe to be the wire for the cabin thermostat but not the sensor itself.  Please help me figure this out.  THanks

Online buswarrior

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Re: OTR Thermostat
« Reply #4 on: April 25, 2018, 03:38:21 PM »
The sensor in an old MC8 had 4 wires attached to it, mounted in the air flow, inside the piping... oh geez... somewhere... maybe a piece of panel came off to expose it?

Long time ago since I had to think about it.

Isn't it in Da Book???

Happy coaching!
buswarrior
Frozen North, Greater Toronto Area

Offline Jcparmley

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Re: OTR Thermostat
« Reply #5 on: April 25, 2018, 07:20:10 PM »
The book shows the sensor but dosen't show the thermal coupler in the vent.  Nor does it show the part number or which wires to wire in a new thermal coupler.  The book is basically useless in regards to how the thermostat gets it's single.

The sensor in an old MC8 had 4 wires attached to it, mounted in the air flow, inside the piping... oh geez... somewhere... maybe a piece of panel came off to expose it?

Long time ago since I had to think about it.

Isn't it in Da Book???

Happy coaching!
buswarrior

Offline RoverScout

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Re: OTR Thermostat
« Reply #6 on: April 25, 2018, 08:59:13 PM »
Mine had a miltery spec style connector, the ones with a screw down collar to lock the plug in place.  Was about half back on the driver side near the floor. 1994 MC-12

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Online buswarrior

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Re: OTR Thermostat
« Reply #7 on: April 26, 2018, 06:23:34 AM »
Ah... it was a Carrier system...

I've always wondered if there was an obscure separate vendor manual back then...

Happy coaching!
Buswarrior
Frozen North, Greater Toronto Area

Offline Jcparmley

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Re: OTR Thermostat
« Reply #8 on: May 03, 2018, 02:08:49 PM »
I have the sensor that broke off but it dosen't have a number on it.  Does your book have a part number for the thermal coupler?  Thanks

Jared
The sensor in an old MC8 had 4 wires attached to it, mounted in the air flow, inside the piping... oh geez... somewhere... maybe a piece of panel came off to expose it?

Long time ago since I had to think about it.

Isn't it in Da Book???

Happy coaching!
buswarrior

Online buswarrior

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Re: OTR Thermostat
« Reply #9 on: May 03, 2018, 06:50:10 PM »
My books are all packed up and remote to my location.

Anyone else have the book or a part number?

Happy coaching!
Buswarrior
Frozen North, Greater Toronto Area

Offline thomasinnv

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Re: OTR Thermostat
« Reply #10 on: May 04, 2018, 08:00:37 AM »
You can download parts and service manuals from mci now. I can't remember exactly where but I believe if you go to mcicoach.com tgere is a link at the top of the page that will take you to support documents or manuals or something like that, then select your series etc. Etc.

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Offline Jcparmley

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Re: OTR Thermostat probe
« Reply #11 on: May 18, 2018, 05:33:07 PM »
Does anyone have any idea where I can find a replacement temp probe?  My parts manual dosen't have the part listed.  It's the little probe that goes in the drivers side stainless duct.  THe one that tells the thermostat the ambient temp.  Any help would be greatly appreciated.  Even if you have a manual that contains a part number that would be great.  Or a idea of how to retrofit some other type of probe.  Thanks

Offline eagle19952

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Re: OTR Thermostat probe
« Reply #12 on: May 18, 2018, 07:32:13 PM »
Does anyone have any idea where I can find a replacement temp probe?  My parts manual dosen't have the part listed.  It's the little probe that goes in the drivers side stainless duct.  THe one that tells the thermostat the ambient temp.  Any help would be greatly appreciated.  Even if you have a manual that contains a part number that would be great.  Or a idea of how to retrofit some other type of probe.  Thanks

to feed a relay...?????????

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Donald PH
1978 Model 05 Eagle w/Torsilastic Suspension,8V71 N, DD, Allison on 24.5's 12kw Kubota.

Offline Jcparmley

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Re: OTR Thermostat
« Reply #13 on: May 18, 2018, 09:30:02 PM »
Hi Buswarrior

What would I call the "sensor probe" in the intake duct if I was to do a search on mcicoach.com?  Thanks
Ah... it was a Carrier system...

I've always wondered if there was an obscure separate vendor manual back then...

Happy coaching!
Buswarrior

Online buswarrior

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Re: OTR Thermostat
« Reply #14 on: May 19, 2018, 04:36:25 AM »
Perfect timing, for a brief moment, I am where the books are!

"Sensing unit - coach temperature"
Fwiw, the MC8 part number was 16B-10-33 and is listed in the "heating and air conditioning" section 16 of the parts manual, under "miscellaneous valves, switches, heat and A/C control components"

Just to get some of the wording familiar.

Happy coaching!
Buswarrior



Frozen North, Greater Toronto Area

Online buswarrior

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Re: OTR Thermostat
« Reply #15 on: May 19, 2018, 04:45:22 AM »
And in the MC8 maintenance manual, the sensor lived in 2 different places during this model run.

One accessible inside the coach through the heater duct at the floor, RH side #2 panel, and underneath in the LH #1 luggage bay, in the center control duct.

You need to be suspicious of the 102C models, there were big changes over the top of them, there is likely more than external appearance differences as the 4 stroke engines came onboard, and the HVAC systems continued to evolve.

In all things busnut, Da Books that have all the revisions for your unit number are critical to speeding the job!

Happy coaching!
Buswarrior
Frozen North, Greater Toronto Area

Offline Jcparmley

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Re: OTR Thermostat
« Reply #16 on: May 19, 2018, 10:13:28 AM »
Thank you so very much

.quote author=buswarrior link=topic=32976.msg376190#msg376190 date=1526730322]
And in the MC8 maintenance manual, the sensor lived in 2 different places during this model run.

One accessible inside the coach through the heater duct at the floor, RH side #2 panel, and underneath in the LH #1 luggage bay, in the center control duct.

You need to be suspicious of the 102C models, there were big changes over the top of them, there is likely more than external appearance differences as the 4 stroke engines came onboard, and the HVAC systems continued to evolve.

In all things busnut, Da Books that have all the revisions for your unit number are critical to speeding the job!

Happy coaching!
Buswarrior

[/quote]

Offline Jcparmley

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Re: OTR Thermostat
« Reply #17 on: June 02, 2018, 06:46:38 PM »
Ok, so I now have the new thermocoupler and I wired it where the old one was.  Now the thermostat says 138 rather than -40.  I thought perhaps it was set for Celsius or something like that but I can't figure out how to change it.  Any suggestions?  Thanks

And in the MC8 maintenance manual, the sensor lived in 2 different places during this model run.

One accessible inside the coach through the heater duct at the floor, RH side #2 panel, and underneath in the LH #1 luggage bay, in the center control duct.

You need to be suspicious of the 102C models, there were big changes over the top of them, there is likely more than external appearance differences as the 4 stroke engines came onboard, and the HVAC systems continued to evolve.

In all things busnut, Da Books that have all the revisions for your unit number are critical to speeding the job!

Happy coaching!
Buswarrior


Offline Jcparmley

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Re: OTR Thermostat
« Reply #18 on: October 02, 2018, 08:44:20 PM »
Does anyone know why my thermostat says 138 degrees after I installed a new thermal coupler?

Online buswarrior

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Re: OTR Thermostat
« Reply #19 on: October 04, 2018, 07:49:44 AM »
Mismatched parts, or the unit is defective.

In fleet use, used to see a lot of changed out units for controlling the coach temperature back then, and that was in a first line fleet...

Don't care what the display reads, what does it do to the coach temperature? Numbers displayed are meaningless, set the temp comfortable, and whatever the display says, that's your setting.

Coach up to temp, see if it will cycle the valve that feeds the heater core.

Happy coaching!
Buswarrior

Frozen North, Greater Toronto Area

Offline jraynor

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Re: OTR Thermostat
« Reply #20 on: October 04, 2018, 01:05:08 PM »
Here is the schematic for a post 1993 102A3 with the 65 stud junction box which I believe you have:

Group 6 Page A-2
Jonathan
1986 TMC 102A3 6V92TA Currently Under Reno

Offline peterbylt

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Re: OTR Thermostat
« Reply #21 on: October 05, 2018, 07:58:37 AM »
I am watching this with interest, I have a 1989 96A3, the display on my dash also reads -40.

Before demolition the OTR Air worked, not now, everything seems to be in order, plenty of refrigerant, compressor engages, no cold air.

While I had the floor out I noticed (and tripped over a few times) a wire that leads up the central duct to what I believe is a thermal sensor. This sensor can also be accessed under a plate from the front driver’s side bay.

In the top picture you can see where the wire runs from the central duct into the side.

In the bottom picture you can see where the access plate is for the sensor above the generator.

I will be looking at this over the weekend to see if I accidently pulled the wires loose or otherwise damaged it while the floor was up.








Peter

Tampa Fl,

1989 MCI 96A3, 8V92TA

Offline Jcparmley

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Re: OTR Thermostat
« Reply #22 on: October 05, 2018, 02:34:18 PM »
That's what happened with me.  Everything worked fine before I began the tear out.  When I tore out the stainless duck I broke the thermal coupler.  So I purchased a new thermal coupler, installed it and now my temp reading is -40.  I will try to turn the heat on and see if it responds.  If it does, then perhaps I won't worry about it.



I am watching this with interest, I have a 1989 96A3, the display on my dash also reads -40.

Before demolition the OTR Air worked, not now, everything seems to be in order, plenty of refrigerant, compressor engages, no cold air.

While I had the floor out I noticed (and tripped over a few times) a wire that leads up the central duct to what I believe is a thermal sensor. This sensor can also be accessed under a plate from the front driver’s side bay.

In the top picture you can see where the wire runs from the central duct into the side.

In the bottom picture you can see where the access plate is for the sensor above the generator.

I will be looking at this over the weekend to see if I accidently pulled the wires loose or otherwise damaged it while the floor was up.








Peter

Offline Jcparmley

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Re: OTR Thermostat
« Reply #23 on: October 05, 2018, 02:39:47 PM »
The schematic shows a thermal coupler in the heat duct in the cabin (I replaced that) then it shows one also in the center control duct.  I opened up the center control duck and there is no thermal coupler in there.  It looks like the PO messed with it and rigged something up.  I would post a pic but photobucket isn't working and I don't know of another app to post pics.

Here is the schematic for a post 1993 102A3 with the 65 stud junction box which I believe you have:

Group 6 Page A-2

Offline eagle19952

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Re: OTR Thermostat
« Reply #24 on: October 05, 2018, 03:12:47 PM »
  I would post a pic but photobucket isn't working and I don't know of another app to post pics.
Look below thisthe dialogue pad and there is a BOLD ATTACH.
clic it and choose the photo from your puter...
It will appear :)
Donald PH
1978 Model 05 Eagle w/Torsilastic Suspension,8V71 N, DD, Allison on 24.5's 12kw Kubota.

Offline Jcparmley

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Re: OTR Thermostat
« Reply #25 on: October 05, 2018, 05:33:10 PM »
Here is a pic of the wiring inside the first bay center tunnel.

Offline Jcparmley

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Re: OTR Thermostat
« Reply #26 on: October 05, 2018, 05:34:00 PM »
Here is a pic of the thermostat.