Thermostat A/C Temperature Sensor Location Tuscany

[cmikego74]

We have a 3 zone system and thermostat reads like 91 when it's really in the 70's so it runs continuously. Anyone know where these sensors are located? Tuscany 2014 40RX

[lwmcguir]

Behind and above the couch, passenger side

Wall by 1/2 bath

Master above head of bed

Sun will play tricks on the sensors
I simply adjust the targets
Front sensor is the main one that swings the most

[camperguy99]

Our 2015 Tuscany has the sensors located as mentioned above. I found that the front of the coach one located right above the couch read dramatically high when we occupied the couch. I remove its screws and let it dangle a few inches below that helped some. The best solution I found was to interchange the thermostat for the front of the coach to the sensor located near the bathroom door. Had to move two wires in the thermostat. The AquaHot only has 2 zones for heating so no loss there. Left the cooling wires where they were since I have three AC's.

[lwmcguir]

Originally Posted by camperguy99

Our 2015 Tuscany has the sensors located as mentioned above. I found that the front of the coach one located right above the couch read dramatically high when we occupied the couch. I remove its screws and let it dangle a few inches below that helped some. The best solution I found was to interchange the thermostat for the front of the coach to the sensor located near the bathroom door. Had to move two wires in the thermostat. The AquaHot only has 2 zones for heating so no loss there. Left the cooling wires where they were since I have three AC's.

I think you have the best fix

the one above the couch is useless when the sun is shining and your on AC. seems to work ok on the heat cycle

Yep, your right only two heat zones so no issue

Zone 2 on heat is also the mixing/stirring bypass adding heat to the 1/2 bath so we leave the hot water off until near time to use it

[mjdougherty]

I've got some comments about the 3 zone temp sensors in our 45AT.

We have learned that opening up the cabinet doors above the sensors (for zones 1 and 3) helps to keep the cabinet temperatures down during daylight hours, when the sun heats the coach up like a toaster oven.

The temperature sensors are mounted in a shallow airspace below those cabinets. When the inside of the cabinets heat up so does the airspace. That means the control system is always looking at an inflated temp reading, causing it to run forever, trying to reach its setpoint.

In the evening hours, when the sun is no longer a factor, the a/c system works fairly well. The cabinet doors may then be closed.

We have also learned that the a/c system works best with zones 1 and 3 set to Auto and zone 2 set to fan only. The sensor for zone 2 is on the wall outside the 1/2 bath. It is not affected by the sun like the other sensors. In addition, while in fan mode, the temp sensor does not come into play. The zone 2 a/c merely helps move the cold air from the other two units through the zone 2 ceiling vents. All three a/c's share a common cold air duct that runs the full length of the coach.

By the way, prop the 1/2 bath door open a bit so the cold air from that ceiling vent can escape into the living area. Otherwise your next trip to the bathroom may require a sweater!

If you want to run the zone 2 a/c as well, be sure to direct some of the airflow towards that sensor so the control loop will work properly. It is best to have the laundry doors closed to better reflect that airflow towards the zone 2 sensor on the opposing wall. We almost never use the zone 2 a/c in our coach.

Another thing to consider is the use of the under cabinet lights that are mounted on the same surfaces as the zone 1 and zone 3 sensors. Those little LEDs heat up that airspace above the temperature sensor, and will contribute to the measurement error, day or night. Don't use those lights if you are running the a/c's.

With regard to the heating system (Aquahot), the zone temp sensors are still affected by the LED light fixtures when you are in heating mode. In this case the sensors will be warmer than the surrounding living areas, and the heating system may shut off prematurely, thinking that it has met the desired setpoint. Don't use those LED lights if you can avoid it.

NOTE: Looking at the Aquahot manual it is not clear to me how the Aquahot gets its temperature inputs. As far as I know the a/c system and the heating system share the same three temperature sensors (zones 1, 2 & 3) for climate control in the main cabin. I assume that the control panel mounted above the passenger seat takes the temperature sensor inputs and retransmits them to the Aquahot controller which is mounted in the Aquahot bay. There are two "conventional" thermostats in the basement and the water tank compartment to keep those areas warm during cold weather.

This advice is the result of six years experience with our motohome, learning all of its little quirks and how to compensate for them.

[cmikego74]

First of all, AWESOME information, thanks everyone. So I found all 3 of them located on the main slide out under the upper storage cabinets. Of course how we are parked that entire slide faces sun nearly all day. I did unscrew them and let them hang, temperature readings have dropped a good 10 degrees but they still read a bit high so a/c runs all the time. It feels like all the ducts are connected? My rear zone 3 a/c blows like a freight train when it comes on and my Zone 1 doesn't feel that cold, it seems to never turn off. These things are so inconsistent when parked in the open sun. Think we are going to concentrate on trying to cover skylights and window reflective panels to try and reduce heat gain in the rig.

Has anyone done modifications to A/C units or covers to increase cooling?

[The Gritz Carlton]

Mine (non-Tuscany) are mounted in the same manner, under the cabinets and I have the same issues with them. Right next to a window, under the cabinets that heat up inside. I've cracked the cabinets open a bit on real hot days and it helps a little. I'll probably relocate them some day...but not sure where to move them. It's a poor design.

[lwmcguir]

Originally Posted by mjdougherty

I've got some comments about the 3 zone temp sensors in our 45AT.

We have learned that opening up the cabinet doors above the sensors (for zones 1 and 3) helps to keep the cabinet temperatures down during daylight hours, when the sun heats the coach up like a toaster oven.

The temperature sensors are mounted in a shallow airspace below those cabinets. When the inside of the cabinets heat up so does the airspace. That means the control system is always looking at an inflated temp reading, causing it to run forever, trying to reach its setpoint.

In the evening hours, when the sun is no longer a factor, the a/c system works fairly well. The cabinet doors may then be closed.

We have also learned that the a/c system works best with zones 1 and 3 set to Auto and zone 2 set to fan only. The sensor for zone 2 is on the wall outside the 1/2 bath. It is not affected by the sun like the other sensors. In addition, while in fan mode, the temp sensor does not come into play. The zone 2 a/c merely helps move the cold air from the other two units through the zone 2 ceiling vents. All three a/c's share a common cold air duct that runs the full length of the coach.

By the way, prop the 1/2 bath door open a bit so the cold air from that ceiling vent can escape into the living area. Otherwise your next trip to the bathroom may require a sweater!

If you want to run the zone 2 a/c as well, be sure to direct some of the airflow towards that sensor so the control loop will work properly. It is best to have the laundry doors closed to better reflect that airflow towards the zone 2 sensor on the opposing wall. We almost never use the zone 2 a/c in our coach.

Another thing to consider is the use of the under cabinet lights that are mounted on the same surfaces as the zone 1 and zone 3 sensors. Those little LEDs heat up that airspace above the temperature sensor, and will contribute to the measurement error, day or night. Don't use those lights if you are running the a/c's.

With regard to the heating system (Aquahot), the zone temp sensors are still affected by the LED light fixtures when you are in heating mode. In this case the sensors will be warmer than the surrounding living areas, and the heating system may shut off prematurely, thinking that it has met the desired setpoint. Don't use those LED lights if you can avoid it.

NOTE: Looking at the Aquahot manual it is not clear to me how the Aquahot gets its temperature inputs. As far as I know the a/c system and the heating system share the same three temperature sensors (zones 1, 2 & 3) for climate control in the main cabin. I assume that the control panel mounted above the passenger seat takes the temperature sensor inputs and retransmits them to the Aquahot controller which is mounted in the Aquahot bay. There are two "conventional" thermostats in the basement and the water tank compartment to keep those areas warm during cold weather.

This advice is the result of six years experience with our motohome, learning all of its little quirks and how to compensate for them.

Great overview and everything you brought up has been my experience as well. Zone 1 & 2 control my Aquahot heating zones. The recirculation from the Aquahot will heat up the 1/2 bath when your trying to cool as well.

Instead of not running the compressor on zone 2 i leave it on but keep the fan on manual set on low speed. Your way would work well except when were in very hot temperatures and need all three units.

Thanks for sharing

[lwmcguir]

I have some small squares of space age type insulation that i am going to place between the sensors and cabinet/wall surfaces. I have had these for some time, but we typically try to travel when it is cool, so they were on the back burner.

We had noticed the heat above the theater seating back when the coach was new and never did anything about it other than play the thermostat games.

They are 3x4 inches and will install them next week but won't test them until later in the summer.

[First RV 4 me]

I have small table top fans directed toward the sensors set on low or medium speed. This helps as well as letting the sensors dangle down away from the hot wood there mounted on. Opening the bath door is the best idea I have seen on here. I have looked for places to move the sensor but have no idea where to place them for proper operation.

[cmikego74]

I have been using my Infared Thermometer to measure temperature readings on various surfaces. The front face of the cabinets is a LOT cooler than the bottom, even 4 or 5 inches away. Thought about moving them or rigging up something like a car cabin temperature sensor that uses a small fan to pull air for an accurate reading.

[lwmcguir]

I will post about the effect of the insulation pads later in the summer when it cools enough to get back on the road

Some good ideas brought out for sure