Documentation and Support (North America)

RE:  Software Revision 13B37 has been shipping in AIRSYS controllers since Nov 2012 and does not map alarm outputs that correspond directly with the new VzW shelter standard.  This bulletin shows how to connect the existing AIRSYS alarm outputs to specified locations in the punch down block referenced in the VzW Cell Site Shelter Standards: Alarm Block Low Voltage Wiring Schematic E501.

NOTE: Alarm inputs (DG Run, Smoke/Fire) are not addressed in this bulletin as they correspond directly to the VzW shelter standards

 I. Distribution: 

• Shelter manufacturers purchasing AIRSYS HVAC systems
• VzW corporate engineering

 II. ISSUE:

Present alarm configuration and reporting from AIRSYS ASLLC.2 Lead/Lag controller does not match HVAC alarm connections called out in Verizon Wireless Cell Site Shelter Standards.  This memorandum is a recommendation on the best method for connecting the AIRSYS available form C contact alarms outputs in their present configuration to the available alarm connections listed in the Alarm Block Low Voltage Wiring Schematic drawing E501.

III. RESOLUTION:

The recommendation illustrated in the table below will keep the existing AIRSYS alarm reporting capability presently available so the AIRSYS systems on new shelters will meet alarm reporting commitments already made to specific markets (i.e. 2^nd compressor run)

Rational for mapping recommendation:

#3 AIRSYS High Temp to HIGH TEMP

As listed in the table above if this is connected to the High Temp Alarm thermostat you are getting a redundant alarm.  If either one triggers the high temp alarm will signal.  In series if both are NC.  In parallel if both are NO.

#4 AIRSYS 2^nd Compressor Run to HVAC FAIL 3

The 2^nd compressor run signal is a metric utilized by several markets in the Northeast.  The AIRSYS controller produces the alarm signal whenever the LAG unit compressor is asked to assist the LEAD unit compressor already in Mechanical cooling mode.  Whenever the Lag unit compressor is needed to help maintain site temperature this indicates the match between HVAC capacity and site load is out of compliance.  This can be an important early indication of a degraded HVAC system or a change in the native heat load of the site that warrants a non-critical site visit. 

OUTPUT ALARM WIRING CONNECTIONS