Trane RAUC-IOM-15, Installation & Maintenance Instructions Manual, Page: 44 / 68

44
System Pre-Start Procedures (Continued)
Discharge Air Controller Checkout
(Honeywell W7100A)
Note: The following checkout procedure must be
performed in its entirety and in the sequence given.
The W7100A (7U11) discharge air controller can be
checked out using a highly accurate digital volt-ohmmeter
and the W7100A accessory tool kit (Trane part # TOL-0101
or Honeywell part # 4074EDJ).
1. Turn all control switches to the “OFF” positon to deacti-
vate the Evaporator Fan and the Mechanical Cooling.
2. Turn the main power disconnect switch for the evaporator
fan and condensing unit “OFF”.
3. Disable the mechanical cooling by removing the field in-
stalled evaporator fan auxillary interlock wire from termi-
nal board 7TB5 terminal 3 inside the unit control panel.
4. At the Discharge Air Controller, in the unit control panel,
remove the red dust cover from the test plug socket at
the bottom of the W7100A. Insert the “Test Plug”, from
the kit, into the test plug socket. The test plug overrides
most of the built-in time delays for staging the compres-
sors “On” and “Off”. Refer to the illustration in Figure 4-3
for terminal and control dial identification.
5. Install a jumper across the P and P1 terminals (remote
setpoint input), and another jumper across terminals 6
and 7 (reset input) if reset is enabled.
6. Disconnect the wires from terminals T and T1 (discharge
air sensor).
7. Remove the 3,400 ohm resistor (blue leads) from the test
kit and connect it across terminals T and T1 to simulate a
discharge air temperature of 60 F.
8. Set the “Setpoint F” dial at 56 F or below; then set the
“Control Band F” dial at 2 to minimize the control re-
sponse time.
9. At the Discharge Air controller, verify that the controller
ground wire is connected to the chassis ground. Refer to
the unit wiring diagram that shipped on the unit.
Note: It is not necessary to set the “Reset F” dial
since the factory installed jumper across Terminals
6 and 7 disables this dial.
10. Turn the control circuit switch 1S2, in the unit control
panel, and the main power disconnect switch for the con-
densing unit to the “ON” position.
H A Z A R D O U S V O LT A G E !
HIGH VOLTAGE IS PRESENT AT TERMINAL BLOCK
1TB1 OR UNIT DISCONNECT SWITCH 1S1.
To prevent injury or death form electrocution, it is
the responsibility of the technician to recognize this
hazard and use extreme care when performing ser-
vice procedures with the electrical power energized.
After approximately 2 minutes (time required to drive the
economizer fully open), the LEDs on the W7100 should be-
gin to illuminate as the cooling outputs stage “On”.
11. At the Discharge Air Controller, use a digital voltmeter to
verify there is 24 volts AC across terminals TR & TR.
12. Set the “Setpoint F” dial at 64 F; within 10 seconds, the
LEDs should turn “Off” as the cooling outputs stage “Off”.
13. Immediately readjust the “Setpoint F” dial to 56 F; the
LEDs should begin to illuminate again as the cooling out-
puts stage “On”.
If the unit includes the zone reset option, proceed to the
next step; if not, proceed to step 18.
14. Set the “Reset F” dial at 15 F and the “Setpoint F” dial
at 41 F; then remove the jumper across terminals 6 & 7.
To simulate a call for maximum reset, install the 1780 ohm
resistor (red leads), from the test kit, across terminals 6
and 7. The cooling LEDs should remain lit.
15. Turn the “Setpoint F” dial to 49 F; within 1 to 2 minutes,
the LEDs should turn “Off” as the cooling outputs stage
“Off”.
16. As soon as all of the cooling LEDs are “Off”, remove the
1780 ohm resistor from terminals 6 and 7 and re-install
the jumper across these terminals.
17. Adjust the “Setpoint F” dial to 56 F; within 1 minute, the
LEDs should illuminate as the cooling outputs stage
“On”.
If the system includes an economizer, complete steps 18
through 23 to verify proper economizer control operation; if
not, proceed to step 24.
18. With all of the cooling LEDs “On”, measure the DC volt-
age across terminals R (-) and W (+). The measured
voltage should be 1.7 VDC to 2.1 VDC.
19. Set the “Setpoint F” dial at 64 F to drive the economizer
output to the minimum position.
Within 2 minutes, the LEDs should turn “Off” as the cool-
ing outputs stage “Off”.
In approximately 5 minutes; measure the voltage across
terminals R (-) & W (+). The measured voltage should
drop to approximately 0.2 VDC.
20. Turn the control circuit switch 1S2, in the unit control
panel, and the main power disconnect switch to the
“OFF” position.
21. Remove the wires from terminals R, B, W, & Y.
22. Measure the resistance across the following pairs of ter-
minals, and compare the actual resistance readings with
the values shown below.
W7100 Terminals R-to-W = 226 ohms
W7100 Terminals R-to-B = 432 ohms
W7100 Terminals R-to-Y = 226 ohms