Instruction Manual
83 
Electric Heating Operation 
When  a call  for  heating  (G  and  W1, W2, 
etc.) is made the supply blower motors and 
electric  resistance  heaters  will  energize. 
Heating  is  accomplished  by  passing 
electrical current through a specified amount 
of resistance heaters which will produce the 
required heat. 
On a fault condition the main limit located 
in  the  supply  air  or  the  auxiliary  limit 
located downstream the  supply  blower will 
remove power from all contactors. 
Steam or Hot Water Preheating and 
Heating Operation 
Valve  control  for  steam  and  hot  water 
heating  coils  are  by  others.  Heating  is 
accomplished by passing steam or hot water 
through  the  steam  or  hot  water  coil 
assembly. 
Modulating Electric Preheat 
Electric  preheat  is  used  to  temper  the 
incoming outside air to the unit based on an 
enable  control  signal  and  outside  air 
conditions. Electric preheat has a maximum 
operation  outside  air  temperature  of  60°F 
and  a  maximum  preheat  discharge  air 
temperature of 80°F. 
Chilled Water or Non-Compressorized 
DX Cooling Operation 
Controls for chilled water cooling coils and 
non-compressorized DX coil are by others. 










