Missing temperature sensor

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Missing temperature sensor

March 29, 2011, 08:50:40 am

No problem... but curiosity for now. Even with the help of knowledgeable friends, we cannot locate the rear (bedroom/bathroom) thermostat for our 2003 U295 36-ft coach. The Duo-Therm control in the front is working fine, and the propane furnaces go on/off based on their individual settings. Clearly, the rear t-stat is doing its job. But where the heck is it?

We have searched high and low, and told by a friend that the t-stat should really be at mid-level, not too high, not too low, and not on outside walls. Well, that still didn't narrow it down... and the flashlight hasn't helped either. No sign of the little t-stat anywhere.

Thoughts? Anyone with a similar year/model who can point out where theirs is located? I'll send James T an email, but before doing so, I thought one of the knowledgeable FF members might be able to shed light on this little mystery. Thanks in advance!

Enquiring minds want to know....

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #1 – March 29, 2011, 08:56:07 am

My guess is that you should be looking for the temperature sensor not a thermostat. The thermostat up front serves both front and back, but has a sensor in the rear. IIRC it is about the size of a quarter and is located just below the television in the bedroom.

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #2 – March 29, 2011, 09:07:57 am

Bob... yes, I misspoke... I'm rather "technically challenged"

I did indeed mean the rear temperature sensor, not the t-stat. And, yes, we were advised by a friend that the sensor (I'm a quick learner - ha ha) is about the size of a quarter and is usually located under the wall-mounted TV. However, the only thing under the TV (in the corner, under the shelf for the converter) is the eye for the IR repeater - no sensor. You can see our bedroom configuration in the photo below.

But thanks for your thoughts - and allowing me to clarify my question!

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #3 – March 29, 2011, 09:21:44 am

Quote from: Patricia – March 29, 2011, 09:07:57 am

we were advised by a friend that the sensor (I'm a quick learner - ha ha) is about the size of a quarter and is usually located under the wall-mounted TV.

Pat - what's the small black thing (below the larger, squarish black thing) on the wall leading to the bathroom in the photo you posted? If not a switch, is it slightly domed, kind of finned, somewhat matte black? I think I recall that's what our BR sensor looks like.

Michelle

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #4 – March 29, 2011, 09:39:17 am

Here is a picture of the rear sensor on ours. It is not used anymore on ours since it has two separate thermostats now. I thought it might be similar to yours and help you to find it.

Regards , Mark

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #5 – March 29, 2011, 10:01:57 am

Hey, Michelle... good eyes! But that's the Fantastic Fan control for the hall (we also have another Fantastic Fan in the private bath, just to the driver's side of that location).

Hi, Mark! Thanks for taking the time to post a photo of the sensor. We were told that's what it looks like, and one would think something at least the size of a quarter (and domed/finned, no less) would stick out like a sore thumb. But, nope!

Keep 'em coming - and thanks in advance!

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #6 – March 29, 2011, 10:44:51 am

Mark,

Thanks for the excellent picture. I wondered what that was, as well as wondering where the temperature sensor was for the back. It looks like a solution to both questions. I'll need to verify, but I think that sensor is on the wall below the TV in our 1997 U295.

To expand the question a bit, where is the sensor for the front? An enquiring mind would like to know the locations of both sensors. I'm pleased that Patricia posted the question.

Re: location of bedroom thermostat - 2003 U295 36' non-Aquahot

Reply #7 – March 29, 2011, 12:18:54 pm

Quote from: J. D. Stevens – March 29, 2011, 10:44:51 am

Mark,

Thanks for the excellent picture. I wondered what that was, as well as wondering where the temperature sensor was for the back. It looks like a solution to both questions. I'll need to verify, but I think that sensor is on the wall below the TV in our 1997 U295.

To expand the question a bit, where is the sensor for the front? An enquiring mind would like to know the locations of both sensors. I'm pleased that Patricia posted the question.

For the front, the sensor would be the thermostat itself.

Missing temperature sensor

Reply #8 – April 19, 2011, 11:57:55 am

I think we have posted on this before, but I can't seem to find it to continue. So here is a new thread.

As we mentioned in our earlier thread, we can't find out remote temperature sensor in the bedroom (zone 2). This is more than an academic question.... the control of the rear AC is not good and the bedroom temperature is often much lower than the Comfort Control setting. We have looked high and low (literally) for that sensor.... no luck. Yesterday James Triana directed me to the circuit board on the rear AC unit (access from the roof) and asked if a sensor was connected to that board (at p4 according to the circuit diagram). See below... there is something plugged into the board at that point. But when I went below and looked for that lead (easy to see since it has two small white wires) in the bedroom side of the AC unit, all I find is a connector where I think the remote sensor attaches. Also when I look in the roof area near the TV where the sensor should run from the AC unit to the wall near the bedroom TV, there is nothing there that looks like a sensor. So James and I have come to the conclusion that our coach was built without a rear sensor.

But how could that be? From what I have read a sensor is required for a two AC unit installation. And the Comfort Control does seem to control the rear AC unit (turns it on and off). I would appreciate some info on how the Comfort Control thermostat can work without a rear temperature sensor. I will probably get a sensor and install it near the AC intake.... not ideal, but better than nothing. But before doing that I want to understand the system better.

Thanks in advance!

Re: Missing temperature sensor

Reply #9 – April 19, 2011, 12:58:43 pm

Quote from: George Hatfield – April 19, 2011, 11:57:55 am

I think we have posted on this before, but I can't seem to find it to continue. So here is a new thread.

As we mentioned in our earlier thread, we can't find out remote temperature sensor in the bedroom (zone 2).

Found and merged....

I also sent you photos via e-mail. In our coach, that small connector goes to what we think are the white wires in the left of your photo, which disappear into the coach in the direction of our temperature sensor. Can you find where they terminate (either end) on yours?

Michelle

Re: Missing temperature sensor

Reply #10 – April 19, 2011, 01:40:29 pm

How about a close up pix

Re: Missing temperature sensor

Reply #11 – April 19, 2011, 04:26:53 pm

Thanks for all the photos. I am 99.9% sure there is no remote sensor on our rear AC unit. I can see where the wires to the sensor plug into the AC unit circuit board and I can see where those wires terminate inside the AC unit on the bedroom side. There is a connector there for the actual sensor, but there is nothing there. See the photo below.

So the question is.... how can my two zone motor home Comfort Control thermostat operate without a rear sensor? Could it have been set up in some special way to do so? I will install a sensor (if I can find one), but do I need to do anything else.

To give you an idea of the problem, we were out this morning and the rear (zone 2) setting was 75 degrees. When we got home the bedroom was at 71.5 degrees.

Re: Missing temperature sensor

Reply #12 – April 19, 2011, 04:44:24 pm

George,
The only thing I can think of is that the previous owner (or the original owner) requested to have both units set to the same temperature setting based on the front thermostat setting by wiring-in the rear A/C sensor wiring to the front A/C's (I don't know how this could have been achieved wiring wise). Thus the rear sensor was not wired-in. Is it possible to get a temp. sensor and install it? In the last picture you posted, where is this wire that plugs into the sensor located? If it is in a logical place, can you just put the new sensor there?

Re: Missing temperature sensor

Reply #13 – April 19, 2011, 11:51:22 pm

According to James Triana, I can buy another sensor and plug it into the connector. The difficult part will be running the sensor to a logical location (usually the front corner of the bedroom, passenger side, in our floor plan). James also mentioned some wire conduits that run from the AC to that corner.....see photo below. I have not tried to run anything through them, but will check them out.

Re: Missing temperature sensor

Reply #14 – April 20, 2011, 09:58:34 am

George,
If you have a fish tape you can run it through that opening at the A/C and see where it comes out. I suspect that James has it right and it comes out to the location where most coaches have their sensor located. If you dont have a fish tape, they are relatively inexpensive at Home Depot/Lowes. Don't get the metal tape. I did and had to return it and bought the plastic. The metal tape can cut other wires as you are fishing the line through.

Re: Missing temperature sensor

Reply #15 – April 20, 2011, 10:55:42 am

Quote from: George Hatfield – April 19, 2011, 11:51:22 pm

According to James Triana, I can buy another sensor and plug it into the connector. The difficult part will be running the sensor to a logical location (usually the front corner of the bedroom, passenger side, in our floor plan). James also mentioned some wire conduits that run from the AC to that corner.....see photo below. I have not tried to run anything through them, but will check them out.

Quote from: Peter & Beth – April 20, 2011, 09:58:34 am

George,
If you have a fish tape you can run it through that opening at the A/C and see where it comes out. I suspect that James has it right and it comes out to the location where most coaches have their sensor located. If you dont have a fish tape, they are relatively inexpensive at Home Depot/Lowes. Don't get the metal tape. I did and had to return it and bought the plastic. The metal tape can cut other wires as you are fishing the line through.

You can you plastic bendable pull rods also. Home Depot & Lowes has them.

Re: Missing temperature sensor

Reply #16 – April 20, 2011, 03:40:00 pm

Peter has the right idea, using a fish tape, today I would use the round fiberglass type fish tape, as they will bend, unlike the older type using the flat steel, they do not bend around two different angles very well if at all.
Like most tools, you only need them when you need them, otherwise they are just junk messing up your neat tool display;D

Re: Missing temperature sensor

Reply #17 – April 21, 2011, 09:17:45 pm

I ordered the remote sensor from FOT (they had about 20 of them in stock) and I got a 6' "glow in the dark" flexible rod from Home Depot for pulling the wire. Not sure what purpose the glowing has. And the flexible rod seems to go through the conduit all the way to the outside wall.

But how do I get to the wire channel next to the outer wall? There is a plate (for lack of a better word) covering that area. See the attached photo. I think the wire channel to the area behind the TV is there. Has anyone removed this panel? It appears to be just nailed on, but I thought it might be good to get some advice before removing it.

Thanks in advance!

Re: Missing temperature sensor

Reply #18 – April 21, 2011, 09:25:11 pm

Quote from: George Hatfield – April 21, 2011, 09:17:45 pm

I ordered the remote sensor from FOT (they had about 20 of them in stock) and I got a 6' "glow in the dark" flexible rod from Home Depot for pulling the wire. Not sure what purpose the glowing has. And the flexible rod seems to go through the conduit all the way to the outside wall.

The glow in the dark helps when working in stick house attics.

Quote

But how do I get to the wire channel next to the wall? There is a plate (for lack of a better word) covering that area. See the attached photo. I think the wire channel to the area behind the TV is there. Has anyone removed this panel? It appears to be just nailed on, but I thought it might be good to get some advice before removing it.

I believe that is the wire channel & I think it is held on with velcro.

Re: Missing temperature sensor

Reply #19 – April 22, 2011, 07:10:01 pm

The remote sensor arrived today, but I had to place the sensor in the return air vent for the AC unit (see photo). I removed some of the access panels on the passenger side of the bedroom (near the roof) and I can't get into the wire channel without some serious cutting. So I think I will leave that to the FOT guys when we return next year. Do you think FOT will give me a discount for not putting it in in the first place? The remote sensor seems to be working fine....time will tell.

Update.... The location in the intake was not good. The AC came on too often and for too short a time. So I routed it as shown from the AC unit forward and then to the right along the sliding door track (see below). Finally! We have a remote sensor where it should be.

Re: Missing temperature sensor

Reply #20 – April 23, 2011, 08:09:46 pm

George,

This has been a very impressive piece of detective work on your part as well as figuring out how to make the installation. Just think how much you save by doing all of this yourself. I am impressed.

Re: Missing temperature sensor

Reply #21 – April 24, 2011, 01:07:58 am

Thanks George and thanks to everyone who helped with suggestions! James Triana was the key guy in figuring this out. What would we do without him?!

Re: Missing temperature sensor

Reply #22 – April 24, 2011, 01:49:07 pm

George H., I understand you are there with Jeff and Carol S. You should have plenty of hot air to check the function of the new sensor.

Re: Missing temperature sensor

Reply #23 – April 24, 2011, 08:50:37 pm

George,

Good job, and thanks for the pictures. I now know what the return air grill looks like on a ducted AC, at least I think that is what I am looking at. How did you get the arrows and words on the photos? Some people seem to know how to do that, but I don't, maybe I need photo shop or similar program.

Re: Missing temperature sensor

Reply #24 – April 24, 2011, 11:54:15 pm

Jerry.... I use Photoshop, but other photo editing programs will work for this stuff. Corel's Paint Shop is a good program for a lot less money. Here is a review.

Corel Paint Shop Photo Pro 2011 - TopTenREVIEWS

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