EngA C-TRAC2

A C-TRAC2.1 MANUAL
Page vi March 1999 R1
If the operator is wired to C-TRAC2.1 terminals “ED” and “B” the control voltage will ramp closed (0
VDC) to open (10 VDC).
NOTE:
 If an economizer is in use and a control motor is being operated from the “HT” and
“B” heat ramp output (such as a hot water valve), it must not be on the same power
supply as the econo motor.
 The dampers will go to minimum position for 4 minutes each time that the C-
TRAC2.1 loses power to terminal “A”. This will also cause the C-TRAC2.1 to
resume its heating mode.
Minimum Position is Open Too Much
If the internal minimum position pot is in use the minimum position is adjusted on pot 7 (see diagram).
Note that some applications use a minimum position pot that is external to the C-TRAC2.1. If an
auxiliary pot is used the internal pot will usually be set to minimum. Note that if it is not at minimum, the
setting will be the total of the two pot settings.
Mechanical Cooling Trouble Shooting
Note the comments in the overheating section above about setting the control as a discharge only control
before proceeding.
Cooling Not Running
For the mechanical cooling to operate three things from the C-TRAC2.1 must be satisfied (as well as all
external items relating to the cooling being in proper working order):
1. The economizer signal must have gone to full open.
2. C-TRAC2.1 terminal “A” must be powered.
3. The internal timing circuits must have timed out.
Measure the AC voltage across the C-TRAC2.1 terminals “A” and “N”. This is the ambient lockout
terminal and it must have 24 VAC on it for the mechanical cooling to run. A caution should be noted if a
digital meter is being used to measure these points. Due to floating voltages being read by high
impedance digital meters, it may be possible to misinterpret a reading. Analogue meters put a load on
a circuit and will draw down trace voltages. This will be true of other terminal voltage readings also.
Is the C-TRAC2.1 in the cooling mode?
Is the cooling light on?
Remove one of the discharge sensor wires. With the discharge sensor open circuited the C-
TRAC2.1 will call for maximum cooling. Due to internal timers allow up to 15 minutes for the
mechanical cooling to cycle on.
NOTE: If you turn dipswitch pot 8 "on" you’ll bypass much of the timing. However, you
must remember to reset the switch to "off " when you’re finished or it may result in
loss of compressors or control cycling problems. This bypass switch will greatly
reduce compressor staging times may have a small affect on the mode timing
(heat, economizer, to cooling). If this allows the cooling to run then check the sensor
and/or set point calibration as per the attached values.
Is the cooling being held off on a control external to the C-TRAC2.1?
Consult the wiring diagram in the unit and trouble shoot accordingly.