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. 2nd compressor run)

AIRSYS ALARM OUTPUTS

VzW Cell Site Shelter Standards

(ALARM BLOCK LOW VOLTAGE WIRING SCHEMATIC E501)

Comments

 

 

 

 

 

1

WPU1 Lockout

Maps To

HVAC FAIL 1

2

WPU2 Lockout

Maps To

HVAC FAIL 2

3

High Temp

Maps To

HIGH TEMP

In series with analog sensor

4

2nd Compressor Run

Maps To

HVAC FAIL 3

Works for Two WPU sites

No Connections

HVAC DIRTY FILTER

No Connections

No Connection

HVAC ECONOMIZER FAILURE

No Connection

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 2nd Compressor Run to HVAC FAIL 3

The 2nd 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

 

REF#

VzW Cell Site Shelter Standards

(ALARM BLOCK LOW VOLTAGE WIRING SCHEMATIC E501)

NO/NC

 

Wire to ASLLC.2 Terminals in AIRSYS Lead/Lag controller

AIRSYS Signal Name

NOTE

 

 

 

 

 

 

 

A

HVAC FAIL 1

NC

 

46 & 47

WPU1 Lockout

 

B

HVAC FAIL 2

NC

 

49 & 50

WPU1 Lockout

 

C

HIGH TEMP

NC

 

43 & 44

HIGH TEMP

In series w analog sensor

D

HVAC FAIL 3

NC

 

Unit #2 Controller

J10: NO4 & C4

2nd Compressor Run

 

 

HVAC DIRTY FILTER

NC

 

NONE

N/A

 

 

HVAC ECONOMIZER FAILURE

NC

 

NONE

N/A