A/C Issues??

No repair was done and the mobile tech was from the dealer I bought it from.

All ductwork in tact.

Repairs not authorized by Tiffin may have the warranty denied ie mobile tech.

Have you check the inside of the ducts to ensure that the tape has not come loose and the air is spilling out above the ceiling.

A/C Update - Mobile tech came out today and checked amperage draw on the front unit and it was a little over 9. He said when it is working hard it will draw a little over 12. He measured the vent temp with a probe hooked up to his multimeter. I knew something was off as it measured ambient temp at 55.4 degrees and it was 74 in the coach. That said, it measured the cold air at 28.8 degrees, close to a 30 degree difference.

My infrared measured 74 ambient and 44 at the vent so they agreed more or less. Still no explanation as to why a 15,000 BTU unit can’t get the coach below 85 when it’s 88 outside. I’ve ordered reflective screens for the front window so we’ll see what difference they make, if any.

The tech they sent knew nothing about how to rewire the furnace controls so I will be getting another visit from someone who knows something and during the week so they can contact Tiffin. I looked at the panel in the front drivers side bay and nothing was marked “furnace”.

Alex and Tee wrote:
I agree it wasn’t the right thermometer but it measured something at those temps. It was either the vent or the duct behind the vent.

Furnace problem was simple. I turned the front furnace on and the rear one came on. The rear one turns the front one on. However they both still rely on their own respective temperature sensors. So they run on and on because the sensor in the front won’t turn the rear one off.

The front touch control turns on the front a/c and the front heat pump but the rear furnace. The rear touch control turns on the rear a/c and the front furnace.

This is a simple fix on the spyder system. Just swapping the rear and front furnace 2 wires at the spyder module. Doug

PS, SHOULD have been caught at the PDI by the selling dealer.

I agree it wasn’t the right thermometer but it measured something at those temps. It was either the vent or the duct behind the vent.

Furnace problem was simple. I turned the front furnace on and the rear one came on. The rear one turns the front one on. However they both still rely on their own respective temperature sensors. So they run on and on because the sensor in the front won’t turn the rear one off.

The front touch control turns on the front a/c and the front heat pump but the rear furnace. The rear touch control turns on the rear a/c and the front furnace.

Alex and Tee wrote:
Doug - thanks for your input. The digital thermometer I used is a Jumper digital thermometer. The “House” symbol indicates object measurement mode. It seems to be accurate with other similar type measurements. The readings I got were taken right at the vent with both a/c’s running. Although this is not perhaps the right tool to use it’s what I had and I doubt it would be 20 degrees off.

I have the mobile tech from La Mesa RV coming next Saturday to fix my reversed furnace wiring and some other things. I will have them check both a/c units while they are here. I would imagine they have a more appropriate measuring device for the application.

My google search of a Jumper Digital Thermometer indicates it is a IR/thermal type Medical thermometer. Which, I stated you CANNOT use. IR thermometers CANNOT sense AIR. They sense solids. Reversed Furnace wiring????? How did you determine that? Not what may be causing your cold problem, just want to know what your furnace problem is and how you determined it is reversed. Doug

Doug - thanks for your input. The digital thermometer I used is a Jumper digital thermometer. The “House” symbol indicates object measurement mode. It seems to be accurate with other similar type measurements. The readings I got were taken right at the vent with both a/c’s running. Although this is not perhaps the right tool to use it’s what I had and I doubt it would be 20 degrees off.

I have the mobile tech from La Mesa RV coming next Saturday to fix my reversed furnace wiring and some other things. I will have them check both a/c units while they are here. I would imagine they have a more appropriate measuring device for the application.

OP Listen to Doug - He has more experience and knowledge than anyone else on this board that I'm aware of.

You have the 2022 Tiffin Open Road? If so, you have a problem. A Tiffin in 85 ambient will freeze you out with 2 AC units. I would set the front at 65 degrees and the rear at 75 and then see what happens. Your Tiffin has the inside temp sensors mounted in the ceiling drivers side next to a cold air vent. 1 in the Bedroom and 1 in the living room. Also, turn the rear OFF and run the front at 65 degrees. Test after at least 1 hour. The air output in the living room should be at least 60 degree output. It will probably be in the 50 to 55 range. Your 42 and 43 are NOT correct or accurate. Your Thermometer is not designed for what you are testing. The Delta difference is 18 to 22 degrees. That means at your 42, the warm INPUT would be 62 degrees which is enough to freeze you out. So, based on my 42 years as a RV Tech (Tiffin dealer tech also), your temp measurements are not good/correct at all. Doug

PS you state digital thermometer set on house mode. NEVER heard of that type thermometer and I would not use such a appliance. Click this link for what you should use. ALSO, you CANNOT use a IR type Thermometer.

https://www.oreillyauto.com/detail/c/robinair/tools---equipment/measuring-tools/thermometers/bbe3c38dae59/robinair-thermometer/rob0/43230?pos=8