Thermostat reads wrong temperature

[bligh]

Hi. Im new to marine AC, but I sure like it a lot!
But one (maybe 2) of my thermostats is reading the aor temperature 10 to 15 degrees lower than the actual air temp. Im curios if there is a quick fix for this. Can the temperature sensors or readings be adjusted or calibrated? This seems like an unusual problem. Any ideas? Thanks
Scott

 

[LarryM]

Scott,

The display panel’s built-in air sensor provides excellent room-air temperature sensing when properly located and installed. It is adjustable from the Programming Mode, Parameter 5: Temperature Calibration, and calibrates the ambient sensor within a range of ±10°F. Adjust this parameter to display the correct room temperature reading.

The air sensor location is important. It should be mounted on an inside wall, slightly higher than mid-height of the cabin, in a location with freely circulating air. Do not mount the display in direct sunlight, near any heat-producing appliances or in a bulkhead where temperatures radiating from behind the panel may affect performance.

Install the optional remote air sensor if the display can not be mounted in a proper location for accurately sensing room temperature. Installing the remote air sensor overrides the display’s built-in sensor. Mount the remote air sensor in the return-air stream behind the opening of the return-air grille. Plug its cable (6-pin connector) into the “ALT AIR” socket #J4 in the upper-left corner of the circuit board.

 

[OldDan1943]

I cured it by adding compartment fans. Stirs up the air and evens out the room temp. I run my compartment fans 24hrs a day. When the crap out, just replace them.
If you have a gas stove, avoid putting the fans where the have an effect on the flame.

 

[kthoennes]

Had the same issue on my boat, same control panels. Larry's response is spot on. For a long time I'd just mentally correct the one that was off and change the setting accordingly, but we have two AC/reverse heating units on board and sometimes they'd fight with each other because the aft thermostat was off. I wasn't able to easily mount a remote sensor in an alternative location as he suggests, but the manual recalibration was plenty to correct the temp error in the aft thermostat (it read about 8* lower than a test reading in that area). Well, I'm calling it an "error" but it may have been accurate at the sensor inside the wall. Either way, as he says the manual adjustment or recalibration range is 10* and that was plenty.

 

[Todd R]

Here is the manual for your thermostat. Programming starts on page 9 for the temperature reading offset.

https://www.pocketyachtco.com/wp/wp-content/uploads/pocketyachtco.com/2017/10/MarineAirPassportIOmanual.pdf

Todd