I service a Medical Bld. that has a VVT system 30 ton Compressor for cooling and a boiler for heating. My question is the unit shut down on a SE 11 ERROR on the Monitor stat I checked the book and its said its a temp. high limit which mean after 10 mins if the supply duct temp. does not drop below 55 F the unit will shutdown. I Ohmed out the supply duct sensor and got a reading of 19 Mega ohms which I though was real high. I checked on the Monitor stat for that sensor Catagory 5 option 5 it showed FAILED does this mean that the sensor is bad or does it need to be recalibrated
I would try to recalibrate sensor at first. On general, these sensors require recalibration every couple of years.
The SE11 alarm is a Temperature Limit Alarm. If option 4.4 is ON, you will get this alarm if temperature exceeds the settings in 4.5/4.6/4.7/4.8. I would check these settings & see why you exceeded them.
HIGH/LOW TEMPERATURE LIMIT EXCEEDED (SE11)
Heating Mode An alarm is issued when any supply air
sensor in the system is above the first or second stage
heating temperature limit (depending on which stages are
Cooling Mode An alarm is issued when any supply air
sensor in the system is below the first or second stage
cooling temperature limit (depending on which stages are
Heat/Cool Mode Alarms are cleared from the system in two ways:
Cycle power to the thermostat OFF, then ON.
Reset the Unit Thermostat. Initiate a reset by switching
the Unit Reset to the ON (Category 7, Option 11).
The 10 minute timeframe on temperatures is not the same thing. This is the Cool/Heat Error Setpoints in Options 7.9/7.10. If these settings are not reached within 10 min, you will get an alarm of SE07 or SE08. The defaults for these are 0°F and 140°F, in all my years I have never seen anyone change these. I never do to prevent unnecessary alarms.