Community Forums

jerryd13 · 03-28-2023, 03:58 PM

Question concerning location of my 3 ac thermostats.
I have a need to check and or replace what I believe is a bad thermostat on my middle unit. This 40 ' coach has 3 rooftop ac units, can someone tell me the specific location, and if you could take a phone photo and e mail or text it to me I would appreciate that very much.

Proudfox13@gmail.com 804-690-3877

Jerry D

BobGed · 03-28-2023, 04:25 PM

I may not be understanding your question, but you should be able to see the AC units from the ground. You should have two thermostats in the front main cabin. The first one is for the AC unit over the driver's area. The second one is for the unit over the kitchen/dining area.

You should then have a thermostat in the bedroom which of course is for the rear or bedroom AC unit.

To isolate a possible bad thermostat you can remove that one and temporarily connect the thermostat from a working unit. If the suspect unit still doesn't work then you might check for a bad start capacitor as that has been my problem in the past.

jerryd13 · 03-29-2023, 06:47 AM

Bob,
Thank you for replying, my three ac control stations are at a location within 2 feet of each other, so I assume that a temp sensor, Thermistor or similar device must be located at several different places to detect temps at those areas of coach.
I don't yet see them, so are thermostats located inside each ac control unit.?

BobGed · 03-29-2023, 10:22 AM

The thermistors are located on the ceiling close to a return air vent.

Just had another thought. If you still think you have a bad thermostat you might want to make sure the fuse is good.

jerryd13 · 03-29-2023, 02:19 PM

Bob,
Yeah, I just did not look good enough, but I see them know and can verify functionality, and will check fuse.
Thank you, I do appreciate you help.

**Lt Dan** · 03-29-2023, 02:25 PM

What issue are you seeing with the thermostats? A common problem with false temp readings are the remote sensors. One fix for that is to remove the intake grill closest to the sensor, reach in the duct and pull out the wires. Recrimping, or soldering the wires to eliminate a loose or bad connection will eliminate many issues.

jerryd13 · 03-30-2023, 06:10 AM

Thank you for your comment.
Would you know who is best source for new replacement sensors
And mfg.and part number.

Thank you
JerryD

BobGed · 03-30-2023, 06:38 AM

I have been carrying one around for years that I purchased at the Tiffin store. Their part number is 5019418. There is a tag on the part with what I believe is Coleman's part number 6537-318.

Looks like they now might be hard to find. However I did see this eBay listing:
https://www.ebay.com/itm/334569152451

Is your center AC not working at all or just sporadically? If it's the latter I often have to set mine somewhat higher than the front AC when I'm running both.

BradS · 04-03-2023, 09:25 AM

Quote:

Originally Posted by Lt Dan

What issue are you seeing with the thermostats? A common problem with false temp readings are the remote sensors. One fix for that is to remove the intake grill closest to the sensor, reach in the duct and pull out the wires. Recrimping, or soldering the wires to eliminate a loose or bad connection will eliminate many issues.

I replaced one of my thermostats (temp reading was off by 3 to 30 degrees, I think cold air in duct changed reading) and it didn't resolve my issue. Like Lt Dan said, I replaced the splice with a soldered connection and viola, works. When I had a second thermostat start doing the same thing, I used the same fix. Now all is good.

Firedog53 · 04-03-2023, 06:55 PM

The "RV Comfort" stats fail frequently at your coach age. I got 12 years out of mine, but it has passed on to greener pastures. I replaced mine with the Micro Air model that is pretty cool; Wi-Fi and an app and all that... Go to their website and pick your correct model. Good folks, lots of Tech help and assists.

That being said, Tiffin installed a resistor of some sort in line to prevent electrical interference with the stats. A service guy in Red Bay removed mine as he said it really wasn't needed. It cleared up the problems I was having for a couple of years, but the stat finally quit altogether so I recently replaced it with the Micro Air.

jerryd13 · 04-04-2023, 05:19 AM

Good information, thank you for your assistance.
Jerryd

vettenuts · 04-04-2023, 05:56 AM

Quote:

Originally Posted by BradS

I replaced one of my thermostats (temp reading was off by 3 to 30 degrees, I think cold air in duct changed reading) and it didn't resolve my issue. Like Lt Dan said, I replaced the splice with a soldered connection and viola, works. When I had a second thermostat start doing the same thing, I used the same fix. Now all is good.

I attempted this, but I can’t get enough of the wires out to expose the splice.

vettenuts · 04-04-2023, 06:00 AM

Quote:

Originally Posted by Firedog53

The "RV Comfort" stats fail frequently at your coach age. I got 12 years out of mine, but it has passed on to greener pastures. I replaced mine with the Micro Air model that is pretty cool; Wi-Fi and an app and all that... Go to their website and pick your correct model. Good folks, lots of Tech help and assists.

That being said, Tiffin installed a resistor of some sort in line to prevent electrical interference with the stats. A service guy in Red Bay removed mine as he said it really wasn't needed. It cleared up the problems I was having for a couple of years, but the stat finally quit altogether so I recently replaced it with the Micro Air.

One of my original RV Comfort thermostats failed and would turn the A/C on too quickly after shutdown causing compressor lock and high current draw. This resulted in my Hughes Watchdog shutting down power to the whole coach. The Micro-Air thermostat took care of that issue. The new thermostats were a great upgrade.