EWC Controls ULTRA-ZONE NCM-3z Technical Bulletin page 9

LCD System Messages
A Supply Air temperature sensor (P# SAS) is included with the
and utilized, allowing the Installer and the End User to observe the supply air temperature in real time. The
cycle the HVAC system off-line for 4 minutes, if the actual supply air temperature exceeds the active heating or cooling
supply air temperature limit value. If the sensor becomes disconnected or shorts, the
the HVAC system and provide a warning on the LCD screen, that the supply air sensor is in fault mode.
LCD screen examples, showing supply air monitoring notifications are shown below.
Supply TMP
A Supply Air Sensor (#SAS) is a standard accessory
and is included with the NCM-3z. When properly
installed and wired, the NCM-3z will display the real
time supply air temperature of the HVAC system
during all modes of operation (Heat, Cool, Fan & Idle).
If the supply air sensor is not connected, becomes
disconnected, or the sensor fails (shorted/open) the
the LCD screen will display the warning message
shown below.
Air Sensor Fault
Heating & Cooling demands are still honored, but the
NCM-3z cannot cycle the HVAC system off-line, if
supply air temperature limits are exceeded.
If the supply air sensor is properly connected and the
actual supply air temperature exceeds the active
heating supply air temperature limit, the NCM-3z will
cycle the HVAC system off-line for 4 minutes and
display two warning messages.
Note: OTC = "Over Temperature Condition".
Supply OTC*
Heat Delay
After 4 minutes has expired and the actual supply air
temperature has dropped below the active heating
supply air temperature limit, the NCM-3z will resume
heating operations.
NOTE: Even if the supply air temperature moderates
quickly (less than 4 minutes) the 4 minute delay must
expire, before the NCM-3z will resume heating
operations.
EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX 732-446-5362
136°
162°
The 4 minute delay
must count down
to zero before
Heating is allowed
to re-energize.
240s
NCM-3z
. EWC highly recommends that it be installed
If the supply air sensor is properly connected and the actual
supply air temperature exceeds the active cooling supply
air temperature limit, the NCM-3z will cycle the HVAC
system off-line for 4 minutes and display two warning
messages.
Note: UTC = "Under Temperature Condition".
Supply UTC*
Cool Delay
After 4 minutes has expired and the actual supply air
temperature rises above the active cooling supply air
temperature limit, the NCM-3z will resume cooling
operations.
NOTE: Even if the supply air temperature moderates
quickly (less than 4 minutes) the 4 minute delay must
expire, before the NCM-3z will resume cooling operations.
LOCATION: The supply air sensor is typically mounted in
the supply air plenum on Gas, Oil, Hydronic or Straight
Electric heating systems. The sensor can be mounted as
close as necessary to the heat exchanger (within 12")
because it can with-stand temperatures greater than the
HVAC system can produce.
On Heat Pump systems with an Air Handler and integrated
evaporator coil on the negative side of the indoor fan, you
have the option to install the sensor in the blower area.
Remove the sensor from the aluminum tubing and secure
the sensor inside the Air Handler blower section, near the
DX (evaporator) coil. The sensor is now "hanging" directly
in the conditioned return air stream, and will protect the
Heat Pump during cooling and heating mode, but remains
unaffected by the electric strip heat.
120°F if you install the sensor in the Air Handler's blower section.
Temperature variations (dead spots) do occur in the supply
plenum so selecting a good location is important:
* Use the genuine Ultra-Zone sensor (P# SAS), included in the box. Do Not use
other brand sensors or thermistors.
* Install the sensor in the supply plenum, as close to the mid-air stream as
possible, upstream (before) any zone dampers, secondary trunks or branch runs.
* Do Not install the supply air sensor in the bypass duct or return duct.
* Avoid splicing the SAS field wiring and creating additional resistance, which will
affect temperature accuracy.
E-Mail- info@ewccontrols.com
NCM-3z
NCM-3z
will continue to operate
39°
The 4 minute delay
must count down
to zero before
Cooling is allowed
to re-energize.
240s
NOTE: Set the "Gas Limit" to
will
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