SERVICE MANUAL SERVICE CHECKS 1. Build   up   pressure   in   air   system   using   the   air compressor. Bleed off air to cause the compressor to cycle several times. 2. Check and compare the temperature at the inlet and outlet ports. This check can be accomplished  by  holding  your  hand  on  each  of the port areas. CAUTION The   inlet   port   be   very   warm   and   The inlet port may be very warm and  a  burn could result. The  inlet  port  should  be  warmer  than  the  outlet port; the outlet port should be at or slightly above ambient     temperature.     Since     the     vehicle     is stationary,   the   unit   will   become   warmer   than normally    experienced    during    over    the    road operation.  If  both  inlet  and  outlet  temperatures are high or at the same temperature (about 660 C or 1500 F) the deflector will need servicing. 3. Hold   a   clean   shop   towel   under   the   unloader (exhaust)  port  and  make  the  air  compressor  go through   several   "unload"   cycles.   Catch   water from   the   unloader   port.   If   water   is   oily,   the compressor    should    be    checked.    If    water    is "brownish" or if brown particles are expelled, the deflector requires servicing. 4. After  the  heat  exchanger  has  "exhausted"  and while  the  air  compressor  is  in  "stand-by"  mode, hold  your  hand  under  the  unloader  port.  If  air flows  out  the  port,  the  check  valve  at  the  top (outlet port) of the heat exchanger is stuck open and  requires  service,  or  the  compressor  inlet  is connected to the outlet side of the turbocharger. 5. If   air   leaks   past   the   exhaust   port   while   the compressor is building up pressure, the unloader valve is stuck open and requires attention. 6. While the air compressor is building up pressure, it  is  normal  for  the  check  valve  to  produce  a rattling sound through rapid opening and closing. 7. When the air compressor is rebuilt or replaced or if the heat exchanger is moved from one vehicle to   another   it   is   recommended   that   the   heat exchanger unit be completely disassembled and cleaned. If the unloader valve should stick in the open position while    the    vehicle    is    on    the    road,    the    air    system can be restored by threading a pipe plug into the exhaust port.      By   doing   this,   the   air   system   pressure   can   be restored but moisture, etc. cannot be exhausted from the air   dryer.   The   unit   should   be   serviced   as   soon   as possible by repairing the unloader valve. DISASSEMBLY AND REASSEMBLY General Instructions Before  any  work  is  accomplished,  it  is  important  for your safety and the cleanliness of your system to adhere to the following: 1. The area surrounding the unit, and the unit itself, should be  thoroughly  cleaned  to  remove  dirt,  oil and other road grime. 2. Set parking brake. 3. Relieve ALL AIR from vehicle’s air system. 4. Relieve   pressure   in   line   from   "UNL"   port   of compressor   governor   to   unloader   port   in   the center of the large nut on the bottom of the unit. Each part of the heat exchanger can be serviced by   means   of   using   the   various   service   and replacement kits available. Servicing Unloader Valve There  are  several  indications  which  may  mean  that the  unloader  valve  of  your  heat  exchanger  unit  needs servicing: The  compressor  goes  into  "stand-by"  mode  but cycles rapidly. Air flows from the exhaust port when compressor is attempting to build up pressure in the air system. The   unit   does   not   "unload"   when   compressor goes into stand-by mode. These situations can be caused by several conditions. Check the TROUBLE SHOOTING GUIDE to make  sure  that  the  probable  cause  is  a  malfunctioning unloader  valve  on  the  CR  BRAKEMASTER  unit.  If,  the probable cause is the unloader valve, it could mean that a piece of debris is clogging this valve, and it only needs to be cleaned, or that the valve assembly itself has been worn   and   needs   to   be   replaced.   In   either   case,   the following   steps   should   be   taken.   Refer   to   Fig.   24   for numbers in parenthesis. 1. Disconnect electrical wire to heater. 2. Disconnect inlet air line from bottom cap. CTS-4079 - CHAPTER XIV - Page 13