The numbers it is showing for the temp.

yes thermastat maybe bad check sencer for temp it maybe bad

No it means you 50 degree one is working better than perfect. Clean the one that is only getting down to 60 degrees but remember if a unit is dropping the air temp by 20 degrees its working fine. You ck this by cking the air at the intake where the filter is say temp is 80 degrees and then take a reading at a discharge vent where the cold air comes out if its 60 you have a 20 degree drop and that is considered good. If the unit was low on freon the unit will freeze up (ice will form on the inside coil).

I had the same problem and went by the meercedes dealer and was told this is the normal temp range regardless of the km. They indicated the range should be above 80. Note it will problem reach this temp zone quicker on hotter days with use of your AC. The dealership can verify this and may add some antifreeze if needed.

see if the lines the big one if it is verry cold or frosted let me know

you shouldnt need to adjust the burners for a temp problem.
the control has a built in calibration setting and it should be described in your owners manual.
if you dont have the manual, then try to set the oven temp to max, 550, and then hold the bake button in for 10 to 30 seconds. after that it should beep and show you a 2 digit number like 00. that is the calibration mode, then you can adjust it up or down +/- 35 degrees. try to make a small adjustment first like 10 degrees and see how it bakes.
if it takes too long to bake, then use + degrees, if it is burning things then lower -10 degrees.
hope that helps you.

You will need to locate a lower temperature range thermostat.The thermostat you have allows a range that is more in line with the "human comfort" range, which is 60-90 or so degrees.
You will probably not be able to get a stat that will replace the one in the Rinnai.
I cannot find the model number you've indicated on the Rinnai website to help you further.

YOUR ENGINE OPERATING RATING TEMPERATURE SUPPOSE TO BE 190 TO 200 DEGREES. IF COOLANT SENSOR DEGREES IS SHOWING 190 OR 200 DEGREES IT WORKING.THAT RIGHT.IF ITS SHOWING 60 OR 80 DEGREES IT FAULTY. AND ENGINE WILL RUN POORLY.

Entirely possible and in range. Depends on outside temps and type of driving. The radiator is colled by electric cooling fans, controlled by temp sensors. Fans should come on automatically when a/c is turned on

No, that is just fine. As a matter of fact, older ranges often had 50 to 60 degree swings in temp. Your oven temp (assuming your thermometer is dead on accurate) is 347 + 365 / 2 = 356 degrees when set at 350. I never mess with ovens which are within 10 degrees of set temp. (when checking the temps, make sure to take the readings after the oven has cycled on and off at least three times, and use a good digital oven calibration thermometer)

Sounds like your oven probe sensor has got issues. Pretty easy to fix, just look inside oven for the probe (small round cyclinder, about a pencil width or smaller, mounted usually in the back top corners), remove the two screws, then slide it out. Some models have the probes where you will have to take the back off to get to them. If your probe is ok, then you might possibly have an issue with your main oven control, which may be computer or knob type. These (especially if computer driven) can be very expensive to fix, and some need calibration. Good luck and let me know if you need any other assistance.