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Manual 2100-467K 
Page 
18 of 24
lOW Pressure sWItch, bYPass, anD 
lOcKOut sequence (standard Feature)
If the low pressure switch opens for more that 120 
seconds, the compressor contactor will de-energize 
and go into a soft lockout.  Regardless the state of the 
low pressure switch, the contactor will reenergize after 
the delay-on-make time delay has expired.  If the low 
pressure switch remains open or opens again for longer 
than 120 seconds the unit will go into manual lockout 
condition and the alarm circuit will energize.  Recycling 
the wall thermostat resets the manual lockout.
alarm OutPut
Alarm terminal is output connection for applications 
where alarm signal is desired.  This terminal is powered 
whenever compressor is locked out due to HPC or LPC 
sequences as described.
NOTE:  Both high and low pressure switch controls 
are inherently automatic reset devices.  The 
high pressure switch and low pressure switch 
cut out and cut in settings are fixed by specific 
air conditioner or heat pump unit model.  The 
lockout features, both soft and manual, are a 
function of the Compressor Control Module.
aDJustments
aDJustable DelaY-On-maKe anD  
DelaY-On-breaK tImer
The potentiometer is used to select Delay-on-Break 
time from 30 seconds to 5 minutes.  Delay-on-
Make (DOM) timing on power-up and after power 
interruptions is equal to 2 minutes plus 10% of Delay-
on-Break (DOB) setting:
  0.5 minute   (30 seconds)  DOB  =  123 second DOM 
  1.0 minute   (60 seconds)  DOB  =  126 second DOM 
  2.0 minute  (120 seconds)  DOB  =  132 second DOM 
  3.0 minute  (160 seconds)  DOB  =  138 second DOM 
  4.0 minute  (240 seconds)  DOB  =  144 second DOM 
  5.0 minute  (300 seconds)  DOB  =  150 second DOM
FIGure  7
lOW ambIent cOntrOl WIrInG
lOW ambIent cOntrOl
Optional Low Ambient Control
An optional low ambient control is available for both 
factory and field installed options.  The low ambient 
control is to be applied to the PA13 Series models when 
operation below 55° outdoor conditions are anticipated.  
Without this device, the evaporating pressure would fall 
off, and the indoor coil would ice over.
The fan cycling control cycles the fan motor on, once 
the liquid refrigerant pressure reaches 350 psig, and 
off, once it has dropped to 225 psig.  It will continue to 
cycle between these parameters depending on outdoor 
temperatures and the load/stage of the system.
This cycling maintains a minimum liquid pressure 
affecting the minimum suction pressure.  This effect 
insures an evaporating temperature that is slightly above 
the point of ice formation on the evaporator.
This field installed option is Bard Part #CMA-28.  See 
Figure 7.